Twin Rate Research Articles

Trends in Twin Births and Survival in Rural Spain: Evidence from 18th to 20th Century.

This study examines the changes over time of the twinning rate and infant and child mortality across 17 rural villages in the province of Zaragoza (Spain) over a span of 200 years. The aim is to understand how the twinning rate evolved in conjunction with the processes of economic and social modernization, as well as the demographic transition. During the period analyzed, the twinning rate increased by 10%, rising from 1.26 per 1000 births in the second half of the 18th century to 1.38 per 1000 births in the first half of the 20th century. This rate varied due to hereditary issues, biological factors such as the mother's age and parity, and socioeconomic features like family occupation and the mother's education level. In terms of child mortality, twins historically faced a significantly higher mortality rate. However, they benefited greatly from the mortality transition, at least in absolute numbers. While nearly 60% of twins did not survive beyond 5 years of age in earlier periods, the mortality rate for twins decreased to 40% by the first half of the 20th century. The excess mortality was particularly severe for girls, driven by a widespread preference for sons, which led to higher mortality rates for girls in the first 5 years of life, especially in the earliest months. These findings help us understand the improvements in uterine and childhood survival rates for contemporary twins, which can be attributed to the socioeconomic and medical advancements of the 20th century.

The transfer of double cleavage embryos developed from two four-cell embryos may not represent an optimal treatment strategy in cycles with a greater number of four-cell embryos on Day 2.

This study examined the impact of the number of Day 2 four-cell (D2-4C) embryos on double embryo transfer and blastocyst culture therapy in the first invitro fertilization (IVF) cycle. A retrospective review was performed on 1039 blastocyst culture cycles to compare outcomes between available and unavailable blastocyst cycles, emphasizing the relationship between the number of D2-4C embryos and blastocyst availability. Furthermore, the correlation between four-cell embryo counts and live births was analyzed in 986 transfer cycles. The analysis revealed that the number of D2-4C embryos independently influenced the availability of blastocysts (odds ratio [OR] 1.693, 95% confidence interval [CI] 1.306-2.195, P < 0.001). Receiver operating characteristic (ROC) analysis indicated that D2-4C embryos displayed the highest predictive value for available blastocysts, with an area under the curve (AUC) of 0.861 (95% CI 0.826-0.896). The cut-off point was determined to be 4.5, particularly for individuals younger than 25 years, where the AUC reached 0.927. This suggests that the number of D2-4C embryos has significant predictive value for available blastocysts. The live birth rate (LBR) of fresh embryo transfers significantly increased with the number of D2-4C embryos (P = 0.004). LBRs for zero, one, and two four-cell embryos in double cleavage embryo transfer were 20.24%, 34.97%, and 38.08%, respectively (P = 0.005). In the twin group, the percentages for zero, one, and two four-cell embryos were 1.21%, 9.75%, and 89.02%, respectively (P < 0.001). Single blastocyst transfer achieved an LBR comparable to that of two four-cell embryos (34.8% vs 39.0%, P = 0.415), while the twin rate significantly decreased with single blastocyst transfer (25.17% vs 1.40%, P < 0.001). The number of D2-4C embryos exhibits significant predictive value for available blastocysts, particularly among young women. Furthermore, most twins resulted from the transfer of double cleavage embryos derived from two four-cell embryos. Consequently, when the D2-4C count exceeds four in a cycle, blastocyst culture therapy is preferred over double cleavage-stage embryo transfer.

Functional landscape of genome-wide postzygotic somatic mutations between monozygotic twins.

Monozygotic (MZ) twins originate from a single fertilized egg, making them genetically identical at the time of conception. However, postzygotic somatic mutations (PZMs) can introduce genetic differences after separation. Although whole-genome sequencing (WGS) sheds light on somatic mutations in cancer genomics, its application in genomic studies of MZ twins remains limited. In this study, we investigate PZMs in 30 healthy MZ twin pairs from the Osaka University Center for Twin Research using WGS (average depth = 23.8) and a robust germline-calling algorithm. We find high genotype concordance rates (exceeding 99%) in MZ twins. We observe an enrichment of PZMs with variant allele frequency around 0.5 in twins with highly concordant genotypes. These PZMs accumulate more frequently in non-coding regions compared with protein-coding regions, which could potentially influence gene expression. No significant association is observed between the number of PZMs and age or sex. Direct sequencing confirms a missense mutation in the ANKRD35 gene among the PZMs. By applying a genome-wide mutational signature pattern technique, we detect an age-related clock-like signature in these early postzygotic somatic mutations in MZ twins. Our study provides insights that contribute to a deeper understanding of genetic variation in MZ twins.

The TLI system can help day-3 single cleavage embryo transfer to obtain comparative clinical outcomes to day-4 or day-5.

The aim was to explore whether the time-lapse imaging system can help day-3 single cleavage embryo transfer to obtain comparative clinical outcomes to day-4 or 5. The data of 1237 patients who underwent single embryo transfer from January 1, 2018, to September 30, 2020, in our reproductive medicine centre were retrospectively analysed. They were divided into the day-3 single cleavage-stage embryo transfer (SCT) group (n = 357), day-4 single morula transfer (SMT) group (n = 129) and day-5 single blastocyst transfer (SBT) group (n = 751) according to the different embryo transfer stage. The clinical and perinatal outcomes of the three groups were analysed and compared. The clinical pregnancy rates of the patients in the day-3 SCT group, day-4 SMT group and day-5 SBT group were 68.07, 70.54 and 72.04%, respectively. The live birth rates were 56.86, 61.24 and 60.99%, respectively. The monozygotic twin (MZT) rate in the day-3 SCT group was significantly lower than that in the day-5 SBT group (P = 0.049). Regarding perinatal outcomes, only the secondary sex ratio had a significant difference (P < 0.05). After age stratification, no improvement was found in the pregnancy outcomes of patients >35 years of age receiving blastocyst transfer. Our findings suggest that for patients with multiple high-quality embryos on day-3, prolonging the culture time can improve the pregnancy outcome to some extent, but it will bring risks. For centres that have established morphodynamic models, day-3 SCT can also achieve an ideal pregnancy outcome and reduce the rate of monozygotic twins and sex ratio.

Prevalence of respiratory distress syndrome in premature twins compared to premature singletons.

To estimate prevalence of respiratory distress syndrome in preterm twins compared to preterm singletons. This is a retrospective observational point prevalence study conducted at the level of three neonatal intensive care units. Medical records of all preterm newborns (<37 weeks of gestation) with respiratory distress syndrome treated in a two-year period were reviewed. The birth order of twins, gestational age and mortality were analysed. Out of 809 preterm newborns, 104 (12.9%) were twins. Median gestational age at birth was 30.3 (IQR 31.4-34.2) weeks. Respiratory distress syndrome was diagnosed in 525 (64.9 %) preterm newborns, of which 441 singletons and 84 twins. Prevalence of respiratory distress syndrome in first-born twins was not significantly higher compared with singletons, 67.3% (35/52) vs. 62.6 % (441/705), respectively (p=0.06). Prevalence of respiratory distress syndrome in second-born twins was 94.2 % (49/52), which was significantly higher compared with both singletons and first-born twins (p<0.001). The mortality rate of preterm newborns was significantly higher in second-born twins compared with singletons and first-born twins, 15.4 % vs. 6.8 % (p<0.001) and 15.4 % vs. 5.5% (p<0.001), respectively. There was a higher risk of respiratory distress syndrome and higher mortality rate in twins compared with singletons, but only in second-born twins the difference was statistically significant.

P-408 Monozygotic twins from in vitro fertilization: can bring the rate closer to that of natural conception?

Abstract Study question Whether the occurrence of monozygotic twins in human in vitro fertilization is associated with zona manipulations, and can we explore approaches to reduce its rates? Summary answer Monozygotic twinning is partially caused by zona manipulation, and it can be lowered by creating a larger opening in the zona before embryo transfer. What is known already While the rate of monozygotic twins in spontaneous conception is 0.5% of live births, the frequency of monozygotic twins after in vitro fertilization-embryo transfer can be a few times higher. Various factors have been suggested to contribute to this phenomenon, including ovarian stimulation, intracytoplasmic sperm injection, embryo cryopreservation, extended culture, embryo quality, maternal age, genetic factors, and micromanipulation of the zona pellucida, such as assisted hatching and biopsy. Due to the fact that the overall rate is low, it is difficult to pinpoint the main reason(s) contributing to it, and there are no effective approach(es) to lower this rate. Study design, size, duration We studied monozygotic twins in 8,063 clinical pregnancies resulting from single blastocyst transfers from 2016 to 2023. Blastocysts, whether fresh or frozen, were transferred with or without biopsy for preimplantation genetic testing and/or blastocyst collapse. Clinical pregnancy, embryo implantation, including twin implantation, and clinical outcomes such as live birth, ongoing pregnancy, and birth weight were further evaluated. Monozygotic twin rates were compared between partial zona removal (larger hole) and no zona removal (small hole) Participants/materials, setting, methods Monozygotic twins were initially evaluated in blastocysts with or without biopsy in 732 clinical pregnancies after fresh or frozen embryo transfer. Subsequently, monozygotic twins were further evaluated in 7331 clinical pregnancies after an approach to open a larger hole in the zona before blastocyst transfer. Additionally, 56 monozygotic twins were evaluated for live birth and birth weight outcomes. Main results and the role of chance In the context of fresh blastocyst transfer, the monozygotic twin rate following biopsy was significantly higher than that for blastocysts that did not undergo zona manipulation (3.4% vs. 0.29%; p = 0.025). After blastocysts underwent biopsy and cryopreservation/warming, the monozygotic twin rate was 2.79%, a similar rate as observed in fresh blastocyst transfer after biopsy. However, when frozen blastocysts (either biopsied and/or collapsed) underwent partial zona removal before transfer, the rate of monozygotic twins significantly decreased to 0.6% (p = 0.00001). When we further examined whether the biopsy procedure increased the monozygotic twin rate (28/4947) under the conditions that partial zona removal was performed by comparing those with blastocysts without biopsy (16/2384), we did not find a significant difference (0.57% vs. 0.67%, p = 0.587) between the two treatments. In this study, there were 34 twin live births (60.7%) including 5 ongoing twin pregnancies, and 9 (16.1%) singleton live births, contributing to an overall live birth rate of 76.8%. Ten cases (17.8%) experienced pregnancy loss with heartbeat cessation during the first trimester. Furthermore, 3 cases (5.4%) had abnormal pregnancies. When the birth weights were evaluated among the monozygotic twins, it was found that lower birth weight (&amp;lt; 1500g) was only observed in twin live birth. Limitations, reasons for caution This study only included data from one large clinic in the US under the conditions and protocols (embryo culture, embryo biopsy, and cryopreservation) used in this clinic. Different patients and protocols would affect the rate differently. Wider implications of the findings Zona manipulations are associated with an increased monozygotic twin rate in both fresh and frozen embryo transfers. This effect can be mitigated by creating a larger opening in the zona before embryo transfer, and this approach can bring the monozygotic twin rate closer to that of natural conception. Trial registration number NA

P-502 Mosaic embryos result in equivalent live birth rates when compared to euploid embryos following frozen embryo transfer

Abstract Study question Are mosaic embryos associated with a lower live birth rate (LBR) than euploid embryos? Summary answer In this adequately powered study, mosaic embryos had nearly identical LBR and similar miscarriage rates (MR) when compared to euploid embryos. What is known already While prior data has suggested that mosaic embryos result in almost half the LBR and three-fold higher MR than euploid embryos, all prior data supports mosaic embryo transfers as safe with acceptable LBRs. Recent studies have suggested a revised selection criteria choosing either euploid or mosaic embryos for transfer based on embryo grade, day of freeze, low level (LL) versus high level (HL) mosaicism and segmental versus whole chromosome mosaicism. Given the lower LBR reported with mosaics, we initially offered double embryo transfer (DET). We initiated this study to assess our LBR, MR, aneuploidy and DET outcomes with mosaics. Study design, size, duration This was a retrospective case-control cohort study. All mosaic embryos (51) that underwent frozen embryo transfer (FET) between January 2020 and June 2023 were compared to all euploid embryos (706) among all patients with tested embryos that underwent FET in the same time frame. Our Power analysis confirmed that with the 14:1 ratio of 706/51 euploid/mosaic embryos this study is sufficiently powered to exclude a &amp;gt; 20% lower LBR following mosaic transfer. Participants/materials, setting, methods All patients seen at our IVF center undergoing FET of mosaic or euploid embryos tested with next generation sequencing during the study period were included. Primary outcome was LBR. Further comparison included age, MR, twin rate, freeze day and grade. Embryos were further analyzed for HL versus LL mosaicism, segmental or whole chromosomal mosaicism, freeze date and grade. Statistics employed chi-squared for categorical and student t-test for continuous data with significance set at p &amp;lt; 0.01 Main results and the role of chance Mosaic embryos resulted in nearly identical LBR when compared to euploid embryos, 26/51(50.9%) versus 359/706(50.85%). Implantation rate was also equivalent, 29/51(54.6%) and 376/706(53.3%). Both biochemical pregnancy [mosaics, 8/45(17.8%) versus euploid 127/683(18.6)], and MR [mosaics 3/29(10.3%) versus euploids 24/373(6.4%)] were not significantly different. Among mosaic embryos, the LBR in LL versus HL mosaics were 17/28 (60.7%) and 9/23 (39.1%), respectively. LBR following segmental only versus whole chromosomal defects were 14/27(51.9%) and 11/24(45.8%). LBR following Day 5 versus Day 6/7 freeze were 10/22(45.5%) and 16/29(55.2%) and LBR for favorably graded embryos were 19/34(55.9%) versus fair to poor graded 7/17(41.2%). None of these achieved statistical significance. While Mosaic embryos were transferred in significantly older patients (37.6 vs 36.1 p &amp;lt; 0.01), there was no difference in mean age associated with LBR (36.1 vs 36.3 p =.4). Additionally, there was no statistically significant difference in LBR between age groups, &amp;lt;35yo 143/259(55.2%), 35-37yo 96/202(47.5%), 38-40yo 96/207(46.4%) or &amp;gt; 40yo 50/90(55.6%) among tested embryos. DET was performed more often with mosaic 19/45 (42.2%) than euploid embryos 36/683 (5.3%) p &amp;lt; 0.001, resulting in significantly higher twin births/LB 5/22 (23.8%) versus 6/356 (1.7%) p &amp;lt; 0.001. All DET data sets included the 13 DETs where one euploid and one mosaic embryo were transferred. Limitations, reasons for caution Our small mosaic numbers may have kept the higher LBR with LL, segmental and good quality mosaic embryos from achieving statistical significance, and may be too small to confirm a higher MR with mosaics. Prospective trials are needed to confirm which euploid or mosaic embryo should be selected for transfer. Wider implications of the findings Given the equivalent LBR, mosaic embryos should be used for transfer prior to repeating IVF retrieval for euploids. The high rate of twin delivery following mosaic DET suggests only eSET should be utilized with any tested embryos. Larger prospective trials are needed to further refine euploid versus mosaic embryo selection criteria. Trial registration number not applicable

O-210 DNA methylation signature of monozygotic twinning: investigating the relationship with medically assisted reproduction, higher-order gestations, and common genetic variants

Abstract Study question To study a DNA methylation signature of monozygotic twins in relation to medically assisted reproduction (MAR), higher-order gestations, and genome-wide common genetic variants. Summary answer Monozygotic twinning and MAR show largely distinct DNA methylation signatures. Monozygotic triplets, like monozygotic twins, carry a comparable but stronger DNA methylation signature. What is known already Monozygotic twins arise when a zygote or embryo splits during pre-implantation stages of development. Higher-order monozygotic multiples including triplets have been hypothesized to arise from multiple consecutive splitting events. The underlying mechanisms are unknown. Some studies have reported a higher rate of monozygotic twins born after the use of medically-assisted reproductive technologies. We recently identified a DNA methylation signature in blood samples from adult monozygotic twins, which showed strong replication across cohorts and in buccal samples from children. This signature consists of 834 differentially methylated locations, enriched for loci with a role in embryonic processes, cell adhesion, and metastable epi-alleles. Study design, size, duration We compared buccal DNA methylation profiles of 934 naturally conceived monozygotic twins to 43 monozygotic twins conceived after IVF/ICSI (mean age=9). We generated monozygotic twinning DNA methylation scores in an independent buccal dataset (59 triplets, 198 twins, and 119 siblings of twins, mean age=15). A genome-wide association study (GWAS) on the DNA methylation score was performed in two datasets from the Netherlands Twin Register (NTR) (1: Blood, N = 2841, mean age=37, 2: Buccal, N = 1150, mean age=10). Participants/materials, setting, methods DNA methylation was assessed with Illumina arrays (450k/EPIC). To study the relationship between DNA methylation and MAR, we performed an epigenome-wide association study (EWAS) of MAR in monozygotic twins. We applied our previously developed DNA-methylation based predictor (trained on blood methylation data from twins using elastic net regression) to novel buccal methylation data from multiples including triplets. GWAS analysis was performed in gcta using --fastGWA-mlm correcting for 10 genetic ancestry PCs and genotype platform. Main results and the role of chance Through EWAS, we identified 29 differentially methylated CpGs in buccal cells from monozygotic twins conceived after MAR compared to naturally conceived monozygotic twins (after Bonferroni correction), of which 8 were previously identified in an EWAS meta-analysis of IVF on cord blood from singletons at birth. None of the 834 CpGs detected in our previous EWAS meta-analysis of monozygotic twinning were associated with MAR, suggesting that they are connected to natural monozygotic twinning. The monozygotic twinning epigenetic signature showed similar performance in buccal DNA methylation data from monozygotic twins as previously observed (81% of monozygotic twins correctly classified). Sensitivity was highest for monozygotic triplets (90% correctly classified), but specificity remains moderate (66% of DZ twins correctly predicted, 53% of non-twins correctly predicted). GWAS analysis of blood 450k array data identified three genome-wide significant loci. The top SNP (rs76157694, MAF=0.25) maps to TBX4; an embryonic transcription factor primarily known for its role in hindlimb development. This finding is consistent with our previous results of MZ-differentially methylated positions being enriched within TBX4 binding motifs. GWAS analysis of the buccal EPIC array data identified no genome-wide significant loci. We are planning a GWAS meta-analysis together with the Genetics of DNA methylation consortium. Limitations, reasons for caution Our research provides compelling hints towards an epigenomic event in monozygotic multiples, but whether the signature represents a cause, effect, or a byproduct of monozygotic twinning remains to be established. In ongoing research, we study the signature in pre- and perinatal tissues from twins (Dutch Fetal biobank and PANDA biobank). Wider implications of the findings The methylation signature may serve as a biomarker to retrospectively diagnose if a person was conceived as monozygotic twin, providing novel opportunities to examine links between vanishing monozygotic twin syndrome and certain congenital disorders. Examples include Beckwith-Wiedemann Syndrome and Amyoplasia (∼10-fold higher frequency of monozygotic twins among patients). Trial registration number not applicable

Comparison of pregnancy outcomes between 4th day morula and 5th day blastocyst after embryo transfer: a retrospective cohort study

BackgroundThis study was designed to evaluate pregnancy outcomes between morulae transferred on day 4 (D4) and blastocysts transferred on day 5 (D5).MethodsFrom September 2017 to September 2020, 1963 fresh transfer cycles underwent early follicular phase extra-long protocol for assisted conception in our fertility center were divided into D4 (324 cases) and D5 (1639 cases) groups, and the general situation and other differences of patients in both groups were compared. To compare the differences in pregnancy outcomes, the D4 and D5 groups were further divided into groups A and B based on single and double embryo transfers. Furthermore, the cohort was divided into two groups: those with live births (1116 cases) and those without (847 cases), enabling a deeper evaluation of the effects of D4 or D5 transplantation on assisted reproductive outcomes.ResultsIn single embryo transfer, there was no significant difference between groups D4A and D5A (P > 0.05). In double embryo transfer, group D4B had a lower newborn birthweight and a larger proportion of low birthweight infants (P < 0.05). The preterm delivery rate, twin delivery rate, cesarean delivery rate, and percentage of low birthweight infants were lower in the D5A group than in the D5B group (P < 0.05). Analysis of factors influencing live birth outcomes further confirmed the absence of a significant difference between D4 and D5 transplantation in achieving live birth (P > 0.05).ConclusionWhen factors such as working life and hospital holidays are being considered, D4 morula transfer may be a good alternative to D5 blastocyst transfer. Given the in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) success rate and risk of twin pregnancy, D4 morula transfer requires an adapted decision between single and double embryo transfer, although a single blastocyst transfer is recommended for the D5 transfer in order to decrease the twin pregnancy rate. In addition, age, endometrial thickness and other factors need to be taken into account to personalize the IVF program and optimize pregnancy outcomes.

P-763 Twin births in Belgium: a national cohort analysis of 35 523 double fresh embryo transfers between 2012 and 2021

Abstract Study question Should a national embryo transfer (ET) policy designed in the era of cleavage stage transfers be adapted for blastocyst transfers to avoid twin pregnancies? Summary answer Double embryo transfer policy results in unacceptable high twin rates at all ages and treatment ranks which is significantly more pronounced after double blastocyst transfer. What is known already In 2003, authorities in Belgium implemented a law to reduce multiple pregnancies after ART by tailoring ET policies based on age, embryo quality, and cycle rank. A choice between SET or Double Embryo Transfer (DET) depending on embryo quality is allowed in the second cycle for patients under 36y with SET being mandatory with top quality embryos. DET is allowed as of the first cycle for patients aged 36y or more regardless of embryo quality. Blastocyst transfer results in significantly higher live birth rates, implying an increased risk of multiple pregnancies after multiple blastocyst transfers. Study design, size, duration A analysis of 35,523 double embryo fresh transfer cycles over a period of 10 years from 2012 to 2021 from the Belgian national BELRAP (Belgian Registry on Assisted Procreation) registry was performed. The study included 26,930 double cleavage stage transfers (DET-CL) and 8,593 double blastocyst transfers (DET-BL). Participants/materials, setting, methods The primary outcomes were delivery rate (DR) per transfer and twin delivery rate (TDR). DR includes all deliveries with a least one live birth per transfer; the TDR includes all twin deliveries as a proportion of all deliveries. For analysis, the data were categorized into the following age groups: 18-25 years, 26-29 years, 30-35 years, 36-39 years and 40-45 years. Cycle ranks were categorized as follows: rank 1, rank 2 and cycle 3- ≥ 6. Main results and the role of chance For all age groups and cycle ranks, delivery rate per transfer and twin delivery rate per delivery were significantly higher after DET-Bl compared to DET-Cl (26.0% versus 19.9%; p &amp;lt; 0.0001 and 28.0% versus 20.6%; p &amp;lt; 0.0001, respectively). In the age groups 26-29 years, 30-35 years and 36-39 years, a significantly higher TDR was observed in DET-Bl compared to DET-Cl, respectively (34.4% versus 24.2%, p = 0.0005; 33.5% versus 24.9%, p &amp;lt; 0.0001 and 24.3% versus 17.3%, p = 0.0002). TDR after DET-Bl was significantly lower in women aged 40-45 years compared to all other age groups, 18-25 years, 26-29 years, 30-35 years and 36-39 years, respectively (11.3% versus 32.8%, p &amp;lt; 0.0001; 11.3% versus 34.4%; p &amp;lt; 0.0001; 11.3% versus 33.5%; p &amp;lt; 0.0001 and 11.3% versus 24.3%; p &amp;lt; 0.0001), respectively). DR was significantly lower in cycle rank 1 compared to cycle rank 2 (22.5% versus 25.5%; p &amp;lt; 0.0001) and compared to cycle rank 3 - &amp;gt; 6 rank 1 and (22.5% versus 27.1%; p &amp;lt; 0.0001). After DET-Bl, a significantly lower TDR was observed in cycle rank 1 compared to cycle rank 2 (15.6% versus 30.0%; p &amp;lt; 0.0001) and compared to cycle rank 3 - &amp;gt; 6 (15.6% versus 29.7%; p &amp;lt; 0.0001). Limitations, reasons for caution The retrospective design is a limitation. Outcomes might be influenced by clinical and laboratory improvements over the years. The registry does not collect embryo quality data making it impossible to assess the effect of embryo quality on the ET policy and outcome. Wider implications of the findings This data indicates that a double blastocyst transfer should only be considered from the age of 40 onwards. In the first cycle, regardless of age, we observe a significantly lower twin delivery rate, suggesting that a double ET is performed when only poor-quality blastocysts are available. Trial registration number Not applicable

Male twinning after the 2008 Obama election: A test of symbolic empowerment

On November 4, 2008, Barack Obama was elected the first Black President of the United States. His campaign and electoral win served as a symbol of hope for a more just future, fostering an “Obama effect” that appears associated with improved well-being among non-Hispanic (NH) Black communities. Situating the Obama election within the symbolic empowerment framework, we consider the potentially protective role of the Obama election on NH Black fetal death, an important but understudied measure of perinatal health that has stark racial disparities. Using restricted-use natality files from the National Center for Health Statistics, we proxy fetal death using the male twin rate (number of twins per 1000 male live births). Male twins have a relatively high risk of in utero selection that is sensitive to maternal and environmental stressors, making the twin rate an important marker of fetal death. We then estimate interrupted time-series models to assess the relation between the Obama election and male twin rates among NH Black births across monthly conception cohorts (February 2003–October 2008). Greater-than-expected male twin rates signal less susceptibility to fetal loss. Results indicate a 4.5% higher male twin rate among all NH Black cohorts exposed in utero to the Obama election, after accounting for historical and NH white trends (p < 0.005). The greater-than-expected rates concentrated among births conceived in the months preceding Obama's nomination at the Democratic National Convention and Obama's presidential win. These results suggest a salutary perinatal response to election events that likely reduced NH Black fetal loss. They also indicate the possibility that sociopolitical shifts can mitigate persisting NH Black-NH white disparities in perinatal health.

Equine chorionic gonadotropin (eCG) treatment in heifers: Double ovulation, twinning rate, and pregnancy losses in twin pregnancies

This study aimed to evaluate the effects of different doses of equine chorionic gonadotropin (eCG; 200 and 300 IU) administered at the end of a fixed-time artificial insemination (FTAI) treatment protocol on ovulation, pregnancy, and twin rates in Bos taurus beef heifers. In addition, pregnancy losses in heifers with singleton and twin pregnancies were determined. A total of 2382 Angus heifers treated with a 6-day estradiol/progesterone-based protocol for FTAI (J-Synch protocol) were randomly allocated to two experimental groups to receive 200 or 300 IU of eCG administered intramuscularly at the time of intravaginal progesterone device removal; FTAI was performed from 60 to 72 h after device removal. The pregnancy rate did not differ (P = 0.89) between the 200 and 300 IU eCG groups. The number of corpus luteum induced by both eCG doses was determined by ultrasonographic examination 14 days after insemination and those treated with 300 IU of eCG had a greater double ovulation rate (P < 0.05). In addition, 300 IU eCG treated heifers had a higher twinning rate on day 30 of gestation (P < 0.05) and parturition (P < 0.05). Pregnancy losses from 30 days of gestation to calving did not differ between heifers treated with 200 and 300 IU of eCG (P = 0.70). However, regardless of the experimental group, heifers bearing twins had greater pregnancy losses than heifers with singletons (P < 0.05). In conclusion, reducing the dose of eCG from 300 to 200 IU under FTAI treatment protocol decreases double ovulation and twinning rates, maintaining a similar pregnancy rate in heifers. Nulliparous cows carrying two fetuses suffer greater pregnancy losses than cows with singletons.

Comparison of perinatal outcome and mode of birth of twin and singleton pregnancies in migrant and refugee populations on the Thai Myanmar border: A population cohort.

In low- and middle-income countries twin births have a high risk of complications partly due to barriers to accessing hospital care. This study compares pregnancy outcomes, maternal and neonatal morbidity and mortality of twin to singleton pregnancy in refugee and migrant clinics on the Thai Myanmar border. A retrospective review of medical records of all singleton and twin pregnancies delivered or followed at antenatal clinics of the Shoklo Malaria Research Unit from 1986 to 2020, with a known outcome and estimated gestational age. Logistic regression was done to compare the odds of maternal and neonatal outcomes between twin and singleton pregnancies. Between 1986 and 2020 this unstable and migratory population had a recorded outcome of pregnancy of 28 weeks or more for 597 twin births and 59,005 singleton births. Twinning rate was low and stable (<9 per 1,000) over 30 years. Three-quarters (446/597) of the twin pregnancies and 96% (56,626/59,005) of singletons birthed vaginally. During pregnancy, a significantly higher proportion of twin pregnancies compared to singleton had pre-eclampsia (7.0% versus 1.7%), gestational hypertension (9.9% versus 3.9%) and eclampsia (1.0% versus 0.2%). The stillbirth rate of twin 1 and twin 2 was higher compared to singletons: twin 1 25 per 1,000 (15/595), twin 2 64 per 1,000 (38/595) and singletons 12 per 1,000 (680/58,781). The estimated odds ratio (95% confidence interval (CI)) for stillbirth of twin 1 and twin 2 compared to singletons was 2.2 (95% CI 1.3-3.6) and 5.8 (95% CI 4.1-8.1); and maternal death 2.0 (0.95-11.4), respectively, As expected most perinatal deaths were 28 to <32 week gestation. In this fragile setting where access to hospital care is difficult, three in four twins birthed vaginally. Twin pregnancies have a higher maternal morbidity and perinatal mortality, especially the second twin, compared to singleton pregnancies.

Comparison of singleton and twin birth weight reference percentile curves by gestational age and sex in extremely preterm infants: a population-based study

BackgroundWith the increasing survival rate of smaller newborns and twins, previous growth curves may not accurately assess the growth of extremely preterm infants (EPIs). Our study aimed to establish birth...

Особенности развития и психическое здоровье близнецов раннего возраста: обзор отечественных и зарубежных исследований

&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Objectives. &lt;/strong&gt;Due to the increasing birth rate of twins and the high risk of delayed physical, cognitive, and psychosocial development in twins at an early age, there is a need to identify factors that contribute to the mental health and developmental trajectory of children.&lt;/p&gt; &lt;p style="text-align: justify;"&gt;&lt;strong&gt;Methods.&amp;nbsp;&lt;/strong&gt;We conducted a review and analysis of recent domestic and international research from 183 articles published between 2009 and 2024, and available in the Scopus, Semantic Scholar, PubMed, Bielefeld Academic Search Engine, Russian Science Citation Index (RSCI) and Crossref databases. The search used the keywords &amp;ldquo;infant twins&amp;rdquo;, &amp;ldquo;twins at early age&amp;rdquo;, &amp;ldquo;twins early development&amp;rdquo;, &amp;ldquo;twins interaction&amp;rdquo;.&lt;/p&gt; &lt;p style="text-align: justify;"&gt;&lt;strong&gt;Results.&amp;nbsp;&lt;/strong&gt;The interest of researchers in different aspects of the mental health and development of children born from monozygotic and dizygotic twin pregnancies is shown. The main factors affecting the health and development of twins are genetic factors, congenital defects, gestational age and birth weight, the presence of trauma during birth, as well as the somatic health of children in the first months of life. The early development of twins is closely related to the features of the care organization and parenting, interaction with the mother, as with a caring adult, a set of environmental factors and conditions for the education. At an early age, twins are at high risk of lagging in general physical, cognitive and speech impairment development compared with singleton, which should be taken into account in monitoring the need for early help for children.&lt;/p&gt; &lt;p style="text-align: justify;"&gt;&lt;strong&gt;Conclusions.&amp;nbsp;&lt;/strong&gt;There is a need for relevant domestic research on the features of the development of twins at an early age. The study of the individual trajectory of early development of each child from twins should be carried out taking into account the factor of discordance in a twin pair.&lt;/p&gt;

The effect of human menopausal gonadotropin and equine chorionic gonadotropin on the reproductive performance of treated ewes with short-term progesterone injections and sponge during the non-breeding season.

This study investigated the effect of human menopausal gonadotropin (hMG) on reproductive efficiency of synchronized ewes with the sponge and progesterone (P4) injection-based protocols. In study 1, anoestrous ewes (n = 120) were used. Sixty ewes were treated with sponge (S) for 12 days. The injection of eCG (SeCG group, n = 30) or hMG (ShMG, n = 30) was given at the time of sponge removal. Thirty ewes received IM injection of P4, three times every 48 h and the injection of hMG was given 24 h after the third P4 injection (3PhMG group, n = 30), and 30 ewes were used as control group. Pregnancy was diagnosed on day 50 after the release of ram. In study 2, 60 ewes were randomly divided into two equal groups. In the treated group with antibiotics (n = 30), before inserting, the sponges were impregnated with the antibiotic penicillin G sodium (5,000,000 IU) and in the control group (n = 30), there was no added antibiotics. Before inserting and after removing sponges, a vaginal cytology sample was taken with a sterile cotton swab. The number of neutrophils in each sample was counted and analysed. The rate of oestrus and total pregnancy was greater in SeCG (96.7, 93.3%), ShMG (82.8, 93.1%) and 3PhMG (67.9, 89.3%) groups compared with the control group (13.8, 41.4%) (p < .05). No significant difference was found in single, twin and total lambing and pregnancy rates after injection of eCG and hMG during the non-breeding season (p > .05). A higher percentage of control ewes had the vaginal smear with neutrophils more than 50% (96.7% vs. 76.7%; p < .05). In conclusion, a single dose of hMG can induce fertile oestrus in synchronized ewes with P4 administered by either injection or intravaginally. Purulent discharge and percentage of neutrophils were significantly reduced in the synchronized ewes by the impregnated sponges with the antibiotic penicillin.

SYSTEMIC LUPUS ERYTHEMATOSUS: UPDATE ΟN THE DIAGNOSIS, PREVALENCE, CLINICAL MANAGEMENT, INFLAMMATORY MARKERS, NEW HORIZONS IN THE PATHOGENESIS, MANIFESTATIONS AND PROGRESS IN TREATMENT

Introduction: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multisystem involvement, generating chronic inflammation and damage of more than one organ. It is usually clinically and serologically diagnosed with the presence of autoantibodies. Lupus is a Latin term meaning wolf, due to the fact that the typical facial eruptions of the pathology are very similar to the bite marks of a wolf. Objective: to detail the current information related to systemic lupus erythematosus, description, etiology, epidemiology, pathophysiology, histology, classification, clinical manifestations, treatment and differential diagnosis. Methodology: a total of 45 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 35 bibliographies were used because the other articles were not relevant to this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: lupus, SLE, autoimmune, multisystemic. Results: Familial segregation and high concordance rates in identical twins strongly suggest a genetic contribution to SLE, however there is no obvious pattern of inheritance. Females have 10 times the risk of developing SLE compared to males. Lupus in males is less common but has a propensity to be more severe. About 80 to 90% of individuals with SLE show musculoskeletal involvement in the course of the disease, ranging from mild arthralgias to deforming arthritis. Avascular necrosis with or without the use of steroids may occur in 10% of individuals with SLE and is most often bilateral and affects the hip joints. Conclusions: systemic lupus erythematosus presents a wide range of clinical and histopathologic manifestations. Adequate education of affected individuals with systemic lupus erythematosus about the possible clinical manifestations can lead to early recognition and intervention, which may prevent potential significant organ damage. The role of markers and autoantibodies in the differential diagnosis of the pathology is essential. Treatment of SLE is aimed at preventing organ damage and achieving remission. The choice of treatment will depend on the altered organ system(s) and the extent of the involvement. Education of the affected individual, physical measures, lifestyle and emotional support play an important role in the comprehensive treatment of SLE. KEY WORDS: lupus, SLE, autoimmune, manifestations, treatment.

A step closer to parenthood with non-obstructive azoospermia: Unveiling the impact of microdissection testicular sperm extraction in Australia's largest single-centre study.

Non-obstructive azoospermia (NOA) diagnosis poses challenges for couples seeking parenthood. Microdissection testicular sperm extraction (MD-TESE) excels in retrieving testicular sperm cells for NOA cases. However, limited live birth data in Australian NOA patients hinders accurate counselling. This study aimed to determine the likelihood of infertile couples with a male partner diagnosed with NOA conceiving biological children using MD-TESE / intracytoplasmic sperm injection (ICSI). A retrospective cohort study included 108 NOA men treated at a public fertility unit and a private fertility centre (May 2009-May 2022). live birth rate (LBR); secondary outcomes: sperm retrieval rate, pregnancy rate, and neonatal outcomes. Among 108 patients undergoing MD-TESE, the positive sperm retrieval rate (PSRR) was 64.8% (70/108). Histology best predicted sperm retrieval success, with hypo-spermatogenesis yielding a 94.1% PSRR. Age, testicular volume, and hormonal parameters had no significant impact. Mean male age: 35.4 years; mean partner age: 32.7 years. Fertilisation rate: 50.7%. LBR per initiated cycle: 58.7% (37/63); per embryo transfer: 63.8% (37/58); per initially diagnosed NOA man: 34.3% (37/108). Cumulative LBR: 74.1% (43/58); twin rate: 10.8% (4/37). No neonatal deaths or defects were observed among 47 live offspring. This study provides valuable data for counselling NOA couples on the probability of conceiving biological offspring. MD-TESE and ICSI yielded favourable PSRR (64.8%) and LBR (63.8%). However, couples should be aware that once NOA is confirmed, the chance of taking home a baby is 34%.

Non-invasive cumulus cell analysis can be applied for oocyte ranking and is useful for countries with legal restrictions on embryo generation or freezing.

Can a strategy for scoring oocyte quality, based on cumulus cell (CC) gene expression, prioritize oocytes with the highest implantation potential, while limiting the number of embryos to be processed in culture and the number of supernumerary embryos to be vitrified? An interventional, blinded, prospective cohort study was retrospectively analyzed. In the original study, patients underwent a fresh Day3 single embryo transfer with embryos ranked based on morphology and CC gene expression (Aurora Test). The additional ranking of the embryos with the Aurora Test resulted in significant higher clinical pregnancy and live birth rates. Now it is investigated if the Aurora Test ranking could be applied to select oocytes. The effect of an Aurora Test based restriction to 2 and 3 2PN or MII oocytes on clinical pregnancy and other outcomes, was analyzed in two subsets of patients with all 2PN (n = 83) or all MII oocytes (n = 45) ranked. Considering only the top three ranked 2PN oocytes, 95% of the patients would have received a fresh SET on Day3 resulting in 65% clinical pregnancies. This was not different from the pregnancy rate obtained in a strategy using all oocytes but significantly reduced the need for vitrification of supernumerary embryos by 3-fold. Considering only top-ranked MII oocytes gave similar results. In countries with legal restrictions on freezing of embryos, gene expression of CC can be used for the selective processing of oocytes and would thus decrease the twin pregnancy rate and workload, especially for embryo morphology scoring and transfers as the handling and processing of lower competence oocytes is prevented, while improving the ART outcome.

Twin births in Yucatan, Mexico during 2008–2020: trends in maternal sociodemographic factors and differences in birth weight and length according to sex of co-twin

Background: Over the years, there has been a noticeable increase in the incidence of multiple pregnancies, due in part to the increased use of assisted reproductive technologies in recent years. The increase in twin pregnancies constitutes a public health challenge due to the adverse outcomes sometimes they entail. Twin pregnancies inherently carry a higher risk of complications, and one of the critical associated factors is the risk of low birth weight. Twin birth weight discordance among different populations can be attributed to differences in non-shared environmental influences. The presence of two or more fetuses in the uterus may lead to an unequal distribution of nutritional and oxygen resources, increasing the likelihood that at least one of the twins will experience insufficient fetal development. Other factors, such as ethnicity, genetics, sociodemographic characteristics, gestational age, parity, and chorion type, have also been related to the birth weight discordance in twin pregnancies. However, it is unclear to what extent the associations between these factors can explain the differences in birth and length size. The frequency of twin births varies among populations and over time, so it is crucial to gain a deeper understanding of the factors contributing to the rise in the twinning rate. The official records of twins continue to make significant contributions to our understanding of the causes of individual differences, and new twin registries are still being created. The recent availability of data from developing countries allows the analysis of trends in regions with sociodemographic and reproductive profiles. Obtaining a more comprehensive understanding of the epidemiology, as well as the related morbidity and mortality, is clinically crucial. Objectives: The aim of the study was to describe the trends of twin births in Yucatan, Mexico during 2008–2021, analyze their association with maternal sociodemographic factors, and compare birth outcomes between types of twin pairs: female-female, male-male, and female-male. Methods: A retrospective cohort analysis was conducted using data from the Mexican Ministry of Health, encompassing information on all births registered in the State of Yucatán, Mexico, from 2008 through 2021. The data was obtained from both public and private hospitals. The variables, including date of birth, sex, gestational age, birth weight and length of newborns, mother´s date of birth, educational level, and number of previous live offspring, were extracted from each dataset. Multiple births (three or more) were excluded from the study. We graphically analyzed the rates (per 1000 births) and percentages of twins according to maternal age, education level, and parity during the study period. A multiple logistic regression model was used to analyze the association between maternal sociodemographic factors and the occurrence of twin births. Comparisons of the gestational age and birth weight and length between types of twin pairs were performed using analysis of variance. Results: A total of 478,118 live births, including 1.4% twins (accounting 6,766 twin births), were analyzed. The rates increased from 11.21 during 2008–2011 to 13.34 during 2012–2017 and reached 20.08 in 2019. The percentages increased in women aged ≥30 years and those with higher educational levels. Older maternal age (coefficient = 0.03; OR = 1.03, per each year), greater education level (coefficient = 0.55 and OR= 1.74 for medium and coefficient = 1.05; OR = 2.57 for high level, compared with no education) and higher parity (coefficient= 0.26; OR = 1.30 per each previous offspring) increased the odds for having twins. Twins’ male-male showed a slightly increased of preterm birth than a co-twin female. Opposite-sex twins showed measurable but small increases in birth weight and length compared with same-sex twins. Conclusion: The rate of twins in Yucatan increased substantially during 2008–2020 in specific sociodemographic groups. Opposite-sex twins were slightly larger than same-sex twins at birth.