Monochorionic Research Articles

The Arabin cervical pessary for the prevention of preterm birth in twin-to-twin transfusion syndrome treated by fetoscopic laser coagulation: a multicenter randomized controlled trial

BackgroundMiscarriage and preterm birth are leading causes of loss and disability in monochorionic twins following laser treatment for twin-twin transfusion syndrome. ObjectiveWe investigated the use of the cervical pessary to reduce preterm birth before 32 weeks in monochorionic diamniotic twin pregnancies after fetal surgery for twin-twin transfusion syndrome. Study designIn this open-label multicenter randomized trial pregnant women carrying monochorionic diamniotic twins requiring fetoscopic laser coagulation for twin-twin transfusion syndrome were randomly assigned in a 1:1 ratio to pessary placement or conservative management. The primary outcome was birth before 32 weeks. Secondary outcomes were birth before 28, 30, 34 or 37 weeks, preterm rupture of membranes, fetal and neonatal survival, and a composite of maternal and neonatal complications. The estimated sample size was 364 patients, with 182 cases in each arm of the study. The analysis was performed according to the intention-to-treat principle. Two interim analyses were planned. ResultsThe trial was stopped prematurely after the first planned interim analysis for futility. One hundred thirty-seven women were included in the analysis, 67 in the pessary and 70 in the conservative management group. A preterm birth before 32 weeks occurred in 27/67 women (40.3%) in the pessary group and in 25/70 women (35.7%) in the conservative management group (aOR, 1.19; 95%CI, 0.58-2.47, P=.63). No significant differences between groups were observed in the rate of deliveries before 28, 30, 34 and 37 weeks, respectively. Overall survival to delivery was 91.2% (125/137) for at least one twin and 70.8% (97/137) for both twins, with no differences between groups. Neonatal survival at 30 days was 76.5% (208/272). There were no differences between groups in maternal or neonatal morbidity. ConclusionIn monochorionic diamniotic twin pregnancies requiring fetal therapy for twin-twin transfusion syndrome, routine use of cervical pessary did not reduce the rate of preterm delivery before 32 weeks.

Metabolic dynamics and prediction of sFGR and adverse fetal outcomes: a prospective longitudinal cohort study

BackgroundSelective fetal growth restriction (sFGR) is an extreme complication that significantly increases the risk of perinatal mortality and long-term adverse neurological outcomes in offspring, affecting approximately 15% of monochorionic diamniotic (MCDA) twin pregnancies. The lack of longitudinal cohort studies hinders the early prediction and intervention of sFGR.MethodsWe constructed a prospective longitudinal cohort study of sFGR, and quantified 25 key metabolites in 337 samples from maternal plasma in the first, second, and third trimester and from cord plasma. In particular, our study examined fetal growth and brain injury data from ultrasonography and used the Ages and Stages Questionnaire-third edition subscale (ASQ-3) to evaluate the long-term neurocognitive behavioral development of infants aged 2–3 years. Furthermore, we correlated metabolite levels with ultrasound data, including physical development and brain injury indicators, and ASQ-3 data using Spearman’s-based correlation tests. In addition, special combinations of differential metabolites were used to construct predictive models for the occurrence of sFGR and fetal brain injury.ResultsOur findings revealed various dynamic patterns for these metabolites during pregnancy and a maximum of differential metabolites between sFGR and MCDA in the second trimester (n = 8). The combination of l-phenylalanine, l-leucine, and l-isoleucine in the second trimester, which were closely related to fetal growth indicators, was highly predictive of sFGR occurrence (area under the curve [AUC]: 0.878). The combination of l-serine, l-histidine, and l-arginine in the first trimester and creatinine in the second trimester was correlated with long-term neurocognitive behavioral development and showed the capacity to identify fetal brain injury with high accuracy (AUC: 0.94).ConclusionsThe performance of maternal plasma metabolites from the first and second trimester is superior to those from the third trimester and cord plasma in discerning sFGR and fetal brain injury. These metabolites may serve as useful biomarkers for early prediction and promising targets for early intervention in clinical settings.

Outcome of monochorionic diamniotic twin pregnancy with selective intrauterine growth restriction, a single center study in China

IntroductionThis retrospective study aimed to evaluate clinical outcomes of monochorionic diamniotic (MCDA) twins with selective intrauterine growth restriction (sIUGR). Materials and methodsMCDA twins, either sIUGR and non-sIUGR, underwent expectant management from 2016 to 2019 in our hospital were included. sIUGR fetuses were classified into three types according to umbilical artery Doppler assessment. Non-sIUGR were considered as the control group. Outcomes were pregnancy outcomes and maternal complications. ResultsForty-three sIUGR (type I: 23; type II: 14, and type III: 6) and 282 non-sIUGR fetuses were included. The sIUGR group had a significantly earlier birth, lower birth weight of the twins, larger inter-twin weight difference, lower Apgar score of the twins, and higher intrauterine fetal death (IUFD) than the non-sIUGR group (all p < 0.001). The same trend was found in the sIUGR type II group compared to type I and III groups. A significantly lower gestational diabetes rate (p = 0.01) and placenta weight (p < 0.001), and higher proportions of abnormal placental umbilical cord insertion (p < 0.001), and ultrasound Doppler monitoring indicators (p = 0.006) were found in the sIUGR group than the non-sIUGR group. ConclusionsThe MCDA twins with sIUGR showed poorer outcomes than the non-sIUGR group. Doppler interrogation was a useful clinical marker for fetal outcome.

The Current Knowledge of Cerebral Magnetic Resonance Imaging in Monochorionic Twins: A Systematic Review of the Last 20 Years

The distinct placental angioarchitecture in monochorionic (MC) pregnancies increases the risk of complications such as twin–twin transfusion syndrome (TTTS), twin anemia polycythemia sequence (TAPS), and selective fetal growth restriction (sFGR). The aim of this systematic review was to evaluate the incidence, type, and severity of cerebral injury and structural brain development on fetal and/or neonatal cerebral magnetic resonance imaging (MRI) in MC twins with or without complications. Twenty-three studies were included, covering a wide range of complications observed during MC pregnancies, with studies involving sIUFD (n = 12), TTTS (n = 7), mixed complications (n = 2), TAPS (n = 1), and uncomplicated MC pregnancy (n = 1). TAPS and sFGR were largely underrepresented in the current literature. The included studies reported that MC pregnancies with single intrauterine fetal demise (sIUFD) are most at risk for cerebral injury during the fetal period. The overall median incidence of cerebral injury after sIUFD was 28.3% (0–55%). Severe antenatal cerebral injury after sIUFD was detected antenatally in 6.5% (0–36%) of the cases. Three of the included studies described the incidence, type, and severity of cerebral injury on neonatal MRI in MC twins. Structural brain development based on cerebral biometry was only assessed in two studies, revealing significantly smaller biometric measurements of the cerebrum in cases of single sIUFD or smaller twins compared to singleton pregnancies. To enhance our understanding of the potential risks and pathophysiological mechanisms associated with cerebral injury and structural brain development in MC twins, there is a need for future studies and standardized protocols using serial fetal and neonatal MRI imaging in addition to routine ultrasound imaging.

Incidence and Perinatal Outcomes of Twin Pregnancy in Tertiary Healthcare Facility, Odisha, India

Background: Assisted reproductive technology has resulted in a progressive rise in the incidence of twin pregnancies, which affect both mother and child in terms of antepartum complications. Objective: To assess the perinatal outcomes of twin pregnancies and the influence of chorionicity on them in a tertiary healthcare facility. Methods: It is a hospital-based cross-sectional study that was carried out in the Obstetrics and Gynecology Department of S.C.B. Medical College Hospital, Cuttack, during the period from 2013 to 2015. All mothers having twin pregnancies (with 28 weeks of completed gestation) admitted to the antenatal (ANC) ward and labor room during this period were taken as a study group, and written informed consent was taken after explaining the details of the study. Results: A total of 150 cases are identified; among them, 98 cases (65.33%) are dichorionic diamniotic, 50 cases (33.33%) are monochorionic diamniotic, and 2 cases (1.33%) are monochorionic and monoamniotic pregnancies. The majority (66%) of the twin pregnancies were between 35-38 wks of gestational age at the onset of labor. It is also observed that macerated births, stillbirths, and neonatal deaths are higher in mono-chorionic twins as compared to dichorionic twins. Conclusions: Twin pregnancies carry a greater risk of adverse outcomes, especially perinatal mortality and neonatal morbidity, in monochorionic twins than dichorionic twins. Good antenatal care, early diagnosis of chorionicity, and antepartum assessment of placentation will prevent mortality and morbidity.

Renal artery Doppler in fetal sonography: A narrative review

Doppler imaging is a non-invasive method in evaluating fetal circulation. Renal artery doppler (RAD) has been used for assessing fetal well-being in several studies. The aim of this narrative review was to accumulate and classify current evidence on RAD in fetal sonography. Articles until November 2022 were searched. After removing ineligible articles, 51 studies were included. Present articles were about RAD assessment in cases with amniotic fluid level changes, fetal growth restriction, fetal renal diseases, monochorionic twin pregnancies, preeclampsia, and gestational diabetes mellitus. The complex physiology of fetal kidney function may explain different results observed in different studies about the role of RAD in fetal assessment. It seems this factor can be useful in assessing some groups like diabetic pregnant women, and it should be used accompanying other related factors like kidney size. Further research is needed to evaluate the effectiveness of RAD in clinical management.&#x0D; Key words: Fetus, Fertilization in vitro, Prenatal ultrasonography, Thymus

TET2-mediated DNA hydroxymethylation of TGFB1 is related to selective intrauterine growth restriction in monochorionic twin pregnancies

IntroductionSelective intrauterine growth restriction (sIUGR), which specifically occurs in monochorionic (MC) twins, usually has a poor prognosis and the underlying mechanisms are not well understood. It is an ideal model for exploring epigenetic-modified mechanisms for fetal development in MCDA twins due to eliminating the interference of different heritable backgrounds and intrauterine environments among individuals. MethodsThe levels of ten-eleven translocation 2 (TET2) and its upstream and downstream targets miR-29b-3p and transforming growth factor beta 1 (TGFB1) were determined using RT‒qPCR, western blotting, and immunohistochemistry. Using TET2 overexpression and knockdown methods, we investigated the role of TET2 in trophoblast functions. The regulatory relationships among TET2, miR-29b-3p, and TGFB1 were explored by cell migration assay, invasion assay, apoptotic ratio assays, Western blot, hMeDIP-qPCR and dual-luciferase assay. ResultsA consistent upregulation of TET2 and TGFB1 was observed in the smaller placental shares compared to the larger placental shares in sIUGR. Gain-of-function studies of TET2 in trophoblasts showed decreased cell invasion and increased apoptosis, whereas loss-of-function studies of TET2 rescued this effect. Mechanistic studies revealed that miR-29b-3p and TGFB1 were the upstream factor and downstream target of TET2, respectively. Furthermore, miR-29b-3p/TET2/TGFB1-smad was identified as a unique axis that regulates trophoblast invasion, migration, and apoptosis in a DNA hydroxymethylation-dependent manner. DiscussionWe elucidated the functional roles of TET2 and DNA hydroxymethylation in trophoblasts and identified a novel DNA regulatory mechanism, providing a basis for further exploration of DNA epigenetic regulatory patterns in sIUGR.

Genetic evaluation for twin pregnancies using karyotyping and single nucleotide polymorphism array analysis

The study aimed to assess chromosomal abnormalities in twin pregnancies using karyotyping and SNP array analysis. The research involved 530 twin pregnancies from two prenatal diagnosis centers between October 2012 and October 2022. Two types of twin pregnancies were considered: monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA), with a total of 177 MCDA and 353 DCDA cases. Chromosomal abnormalities were examined based on chorionic and amniotic sac properties and clinical indications. Among 42 twin pregnancies, 50 fetuses showed chromosomal abnormalities by karyotyping, with 35 cases of aneuploidy in DCDA and 10 in MCDA. Trisomy 21 was the most common aberration, affecting 15 fetuses in DCDA and 4 in MCDA. The rate of discordant karyotypes in MCDA and DCDA groups was 1.1% and 8.8%, respectively. Ultrasound abnormalities and advanced maternal age were frequent indications (55.3% and 39.2%, respectively). Aneuploidy frequencies in DCDA and MCDA pregnancies with advanced maternal age were 10.6% and 4.5%. Cardiac defects and increased nuchal translucency were common anomalies, with higher incidences of chromosomal abnormalities in DCDA (12.5% and 6.9%) and MCDA groups (23.5% and 3.7%). SNP array identified 1.6% clinically significant copy number variants in DCDA fetuses with ultrasound abnormalities, while no significant CNVs were found in MCDA pregnancies. Chromosomal aneuploidies were the primary abnormalities in twin pregnancies, with detectable abnormalities and clinically significant CNVs more likely in DCDA pregnancies, especially those with ultrasound abnormalities.

Amniotic fluid metabolic fingerprinting contributes to shaping the unfavourable intrauterine environment in monochorionic diamniotic twins

Amniotic fluid (AF) is the primary intrauterine environment for fetal growth throughout gestation. Selective fetal growth restriction (sFGR) is an adverse complication characterized by unequal growth in twins with nearly identical genetic makeup. However, the influence of AF-mediated intrauterine environment on the development and progression of sFGR remains unexplored. High-throughput targeted metabolomics analysis (G350) was performed on AF samples collected from sFGR (n=18) and MCDA twins with birth weight concordance (MCDA-C, n=20) cases. Weighted correlation network analysis (WGCNA) was used to identify clinical features that may influence the metabolite composition in AF. Subsequently, partial least-squares discriminant analysis (PLS-DA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to compare the different types of sFGR and MCDA-C twins. Receiver operating characteristic (ROC) and multivariate ROC curves were utilized to explore potential AF markers in twins with sFGR. In our study, 182 metabolites were quantified in 76 AF samples. WGCNA indicated that the metabolite composition in late AF may not be influenced by gestational age. PLSDA demonstrated distinct variations between the metabolite profiles of AF in the sFGR and MCDA-C twins, with a significant emphasis on amino acids as the primary differential metabolite. The dissimilarities observed in sFGR twins were predominantly attributed to lipid metabolism-related metabolites. In particular, the KEGG enrichment metabolic pathway analysis revealed significant associations of both types of sFGR twins with central carbon metabolism in cancer. The multivariate ROC curves indicated that the combination of carnosine, sarcosine, l-alanine, beta-alanine, and alpha-n-phenylacetylglutamine significantly improved the AUC to 0.928. Notably, the ROC curves highlighted creatine (AUC:0.934) may be a potential biomarker for severe sFGR. The data presented in this study offer a comprehensive metabolic map of the AF in cases of sFGR, shedding light on potential biomarkers associated with fetal growth and development in MCDA twins.

Maternal and neonatal outcomes of twin pregnancies complicated by gestational diabetes mellitus

IntroductionGestational diabetes mellitus (GDM) is associated with a higher risk of adverse maternal outcomes, but its effects on maternal and perinatal outcomes of twin pregnancies remain conflicting.MethodsThis retrospective cohort study included all primipara who delivered twin pregnancies at a single tertiary perinatal center between January 1, 2016 and December 31, 2022. Excluded were those who had a single pregnancy, twin pregnancies with pre-existing diabetes, missing information on GDM screening, a delivery before gestational 28 weeks, complications related to monochorionic placentation, multifetal reduction, fetal anomalies, and monochorionic monoamniotic twins. Maternal outcomes included preterm birth, pre-eclampsia, hypothyroidism, preterm premature rupture of membranes (PROM), placental abruption, severe postpartum hemorrhage, and oligohydramnios. Neonatal outcomes included small-for-gestational-age (SGA), large-for-gestational-age (LGA), birthweight, Apgar score, neonatal intensive care unit (NICU) admission, extrauterine growth restriction (EUGR), and neonatal hypoglycemia.ResultsA total of 3269 twins were delivered, with 897 women (27.4%) diagnosed with GDM during pregnancies; moreover, 72 (8.0%) of these women received insulin treatment. The GDM group showed a significantly higher maternal age at delivery (≥35 years), as well as incidences of overweight and obesity. These factors also elevated the odds of insulin treatment in GDM women with twin pregnancies (OR = 1.881, 95% CI = 1.073–3.295, P = 0.027; OR = 2.450, 95% CI = 1.422–4.223, P < 0.001; OR = 4.056, 95% CI = 1.728–9.522, P < 0.001, respectively). Chronic hypertension prior to pregnancy was identified as a risk factor for GDM during twin pregnancies (OR = 1.896, 95% CI = 1.290–2.785, P < 0.001), although it did not increase the proportion of women requiring insulin treatment (P = 0.808). Aside from a higher incidence of preterm birth before 37 weeks in insulin-treated GDM twins (OR = 2.096, 95% CI = 1.017–4.321, P = 0.045), there were no significant difference in other maternal outcomes (preterm birth before 34 weeks, pre-eclampsia, hypothyroidism, PROM, placental abruption, placenta previa, severe postpartum hemorrhage, and oligohydramnios) between the GDM group and non-GDM group, and between insulin-treated GDM and non-insulin-treated GDM. The rate of newborns with birthweight <1500 g was significantly lower among twins born to GDM women, but the prevalence of EUGR was notably higher. Additionally, the risk of EUGR was elevated in insulin-treated GDM twins (OR = 3.170, 95% CI = 1.639,6.131, P < 0.001). No significant differences were observed between the GDM group and non-GDM group, or between insulin-treated GDM and non-insulin-treated GDM group in terms of mean birthweight, newborn sex ratio, and incidences of other adverse neonatal outcomes, including gestational age at delivery, LGA, birth weight <2500 g, and 1-min and 5-min Apgar scores.ConclusionMaternal age ≥35 years, overweight or obesity, and chronic hypertension are significant risk factors for GDM during twin pregnancies. Women with GDM during twin pregnancies may achieve similar outcomes compared to those without GDM. However, the women with GDM during twin pregnancies receiving insulin therapy may have a higher risk of preterm birth and EUGR.

Twin Reversed Arterial Perfusion Sequence: A Case Report and Literature Review

Twin reversed arterial perfusion sequence (TRAPS) is one of the complications of monochorionic twin gestation. It is characterised by large intertwined arterial-arterial anastomosis in which blood flows from one twin (pump twin) to the other twin (perfused twin) in a retrograde pattern.&#x0D; We report a case of monochorionic diamniotic twin gestation complicated by TRAPS in a 38-year-old G4P3 trader who was referred to the antenatal clinic of Rivers State University Teaching Hospital on account of unusual abdominal distension of one-week duration at 31 weeks gestational age. Ultrasound scan done at presentation showed a monochorionic diamniotic twin with the first twin in a transverse lie with an estimated foetal weight of 1.7kg, foetal heart rate of 150beats per minute, and Twin 2, had no foetal head, no cardiac pulsation with significant tissue swelling. A diagnosis of TRAPS was made for which she was admitted and delivered by emergency caesarean section. The pump twin was admitted into the Special Care Baby Unit (SCBU) and succumbed to cardiac failure 24 hours after delivery.&#x0D; Monochorionic pregnancy complicated by TRAPS is associated with poor foetal outcomes. Early diagnosis and adequate management will enhance clinical outcomes. The diagnosis of TRAPS requires a high index of suspicion. Clinicians and radiologists need to be aware of the features in order to make prompt diagnosis and take appropriate action which may include early referral to the fetal medicine unit for appropriate intervention and improved outcome for the pump twin.

Twin reverse arterial perfusion sequence: A case report and literature review

Twin reverse arterial perfusion sequence (TRAPS) is one of the complications of monochorionic twin gestation. It is characterised by large intertwined arterial-arterial anastomosis in which blood flows from one twin (pump twin) to the other twin (perfused twin) In a retrograde pattern. We report a case of monochorionic diamniotic twin gestation complicated by TRAPS in a 38-year-old G4P3 trader who was referred to the antenatal clinic of Rivers State University Teaching Hospital on account of unusual abdominal distension of one-week duration at 31 weeks gestational age. Ultrasound scan done at presentation showed a monochorionic diamniotic twin with the first twin in a transverse lie with an estimated foetal weight of 1.7kg, foetal heart rate of 150 beats per minute, and Twin 2, had no foetal head, no cardiac pulsation with significant tissue swelling. A diagnosis of TRAPS was made for which she was admitted and delivered by emergency caesarean section. The pump twin was admitted into the Special Care Baby Unit (SCBU) And succumbed to cardiac failure 24 hours after delivery

Prevalence and detection rate of major congenital heart disease in twin pregnancies in Denmark.

To investigate the national prevalence and prenatal detection rate (DR) of major congenital heart disease (mCHD) in twin pregnancies without twin-to-twin transfusion syndrome (TTTS)-associated CHD in a Danish population following a standardized prenatal screening program. This was a national registry-based study of data collected prospectively over a 10-year period. In Denmark, all women with a twin pregnancy are offered standardized screening and surveillance programs in addition to first- and second-trimester screening for aneuploidies and malformation, respectively: monochorionic (MC) twins every 2 weeks from gestational week 15 and dichorionic (DC) twins every 4 weeks from week 18. The data were retrieved from the Danish Fetal Medicine Database and included all twin pregnancies from 2009-2018, in which at least one fetus had a pre- and/or postnatal mCHD diagnosis. mCHD was defined as CHD requiring surgery within the first year of life, excluding ventricular septal defects. All pregnancy data were pre- and postnatally validated in the local patient files at the four tertiary centers covering the entire country. A total of 60 cases from 59 twin pregnancies were included. The prevalence of mCHD was 4.6 (95% CI, 3.5-6.0) per 1000 twin pregnancies (1.9 (95% CI, 1.3-2.5) per 1000 live births). The prevalences for DC and MC were 3.6 (95%CI, 2.6-5.0) and 9.2 (95%CI, 5.8-13.7) per 1000 twin pregnancies, respectively. The national prenatal DR of mCHD in twin pregnancies for the entire period was 68.3%. The highest DRs were in cases with univentricular hearts (100%) and the lowest with aortopulmonary window, total anomalous pulmonary venous return, Ebstein's anomaly, aortic valve stenosis and coarctation of the aorta (0-25%). Mothers of children with prenatally undetected mCHD had a significantly higher body mass index (BMI) compared to mothers of children with a prenatally detected mCHD (median, 27 kg/m2 and 23 kg/m2 , respectively; P = 0.02). The prevalence of mCHD in twins was 4.6 per 1000 pregnancies and was higher in MC than DC pregnancies. The prenatal DR of mCHD in twin pregnancies was 68.3%. Maternal BMI was higher in cases of prenatally undetected mCHD. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Pregnancy outcomes of fetal reduction in patients with intrauterine haematoma following double embryo transfer

Research questionIs there an association between intrauterine hematoma(IUH) and pregnancy outcomes in patients receiving fetal reduction(FR) after double embryo transfer? What is the relationship between IUH-related characteristics and pregnancy outcomes? DesignClinical information and pregnancy outcomes of women receiving FR after double embryo transfer were analyzed. Patients with other systematic diseases, ectopic pregnancy or heterotopic pregnancy, monochorionic twin pregnancies and incomplete data were excluded. Stratification of IUH pregnancies was done according to IUH-related characteristics. The main outcome measures included incidence of fetal demise(<24 weeks) while other adverse pregnancy outcomes were considered as secondary outcomes. Result(s)34 IUH patients and 136 non-IUH patients receiving FR after double embryo transfer(DET) were included based on 1:4 match for age, cycle type and fertilization method. IUH patients had higher incidence of early fetal demise(20.6% vs. 7.4%, p=0.048), threatened abortion(48.1% vs. 10.3%, p<0.001) and postpartum hemorrhage(14.8% vs. 4.0%, p=0.030)after FR compared with non-IUH patients, whereas IUH was an independent risk factor for early fetal demise(OR 3.34 95%CI 1.14-9.77) and threatened abortion(OR 8.61, 95%CI: 3.28-22.61) after adjusting for potential confounders. IUH pregnancies undergoing FR resulted in miscarriage had larger IUH volumes and earlier diagnosis. However, IUH characteristics(i.e. volume, changing pattern, presence or absence of cardiac activities) were not correlated with fetal demise and threatened abortion. Conclusion(s)Fetal reduction should be performed with caution in IUH pregnancies after double embryo transfer since the risks of fetal demise is relatively high. Special attention should be given to IUH patients after FR noticing the early signs of threatened abortion and inevitable fetal demise.

Association between placental oxygen transport and fetal brain cortical development: a study in monochorionic diamniotic twins.

Normal cortical growth and the resulting folding patterns are crucial for normal brain function. Although cortical development is largely influenced by genetic factors, environmental factors in fetal life can modify the gene expression associated with brain development. As the placenta plays a vital role in shaping the fetal environment, affecting fetal growth through the exchange of oxygen and nutrients, placental oxygen transport might be one of the environmental factors that also affect early human cortical growth. In this study, we aimed to assess the placental oxygen transport during maternal hyperoxia and its impact on fetal brain development using MRI in identical twins to control for genetic and maternal factors. We enrolled 9 pregnant subjects with monochorionic diamniotic twins (30.03 ± 2.39 gestational weeks [mean ± SD]). We observed that the fetuses with slower placental oxygen delivery had reduced volumetric and surface growth of the cerebral cortex. Moreover, when the difference between placenta oxygen delivery increased between the twin pairs, sulcal folding patterns were more divergent. Thus, there is a significant relationship between placental oxygen transport and fetal brain cortical growth and folding in monochorionic twins.

Association between maternal plasma one-carbon biomarkers during pregnancy and fetal growth in twin pregnancies

Objective: To characterize the relationship between the levels of plasma methyl donor and related metabolites (including choline, betaine, methionine, dimethylglycine and homocysteine) and fetal growth in twin pregnancies. Methods: A hospital-based cohort study was used to collect clinical data of 92 pregnant women with twin pregnancies and their fetuses who were admitted to Peking University Third Hospital from March 2017 to January 2018. Fasting blood was collected from the pregnant women with twin pregnancies (median gestational age: 18.9 weeks). The levels of methyl donors and related metabolites in plasma were quantitatively analyzed by high-performance liquid chromatography combined with mass spectrometry. The generalized estimation equation was used to analyze the relationship between maternal plasma methyl donors and related metabolites levels and neonatal outcomes of twins, and the generalized additive mixed model was used to analyze the relationship between maternal plasma methyl donors and related metabolites levels and fetal growth ultrasound indicators. Results: (1) General clinical data: of the 92 women with twin pregnancies, 66 cases (72%) were dichorionic diamniotic (DCDA) twin pregnancies, and 26 cases (28%) were monochorionic diamniotic (MCDA) twin pregnancies. The comparison of the levels of five plasma methyl donors and related metabolites in twin pregnancies with different basic characteristics showed that the median levels of plasma choline and betaine in pregnant women ≥35 years old were higher than those in pregnant women <35 years old, and the differences were statistically significant (all P<0.05). (2) Correlation between plasma methyl donor and related metabolites levels and neonatal growth indicators: after adjusting for confounding factors, plasma homocysteine level in pregnant women with twins was significantly negatively correlated with neonatal birth weight (β=-47.9, 95%CI:-94.3- -1.6; P=0.043). Elevated methionine level was significantly associated with decreased risks of small for gestational age infants (SGA; OR=0.5, 95%CI: 0.3-0.9; P=0.021) and low birth weight infants (OR=0.6, 95%CI: 0.4-0.9; P=0.020). Increased homocysteine level was associated with increased risks of SGA (OR=1.5, 95%CI: 1.0-2.2; P=0.029) and inconsistent growth in twin fetuses (OR=1.9, 95%CI: 1.0-3.7; P=0.049). (3) Correlation between the levels of plasma methyl donors and related metabolites and intrauterine growth indicators of twins pregnancies: for every 1 standard deviation increase in plasma choline level in pregnant women with twin pregnancies, fetal head circumference, abdominal circumference, femoral length and estimated fetal weight in the second trimester increased by 1.9 mm, 2.6 mm, 0.5 mm and 20.1 g, respectively, and biparietal diameter, abdominal circumference and estimated fetal weight increased by 0.7 mm, 3.0 mm and 38.4 g in the third trimester, respectively, and the differences were statistically significant (all P<0.05). (4) Relationship between plasma methyl donor and related metabolites levels in pregnant women with different chorionicity and neonatal birth weight and length: the negative correlation between plasma homocysteine level and neonatal birth weight was mainly found in DCDA twin pregnancy (β=-65.9, 95%CI:-110.6- -21.1; P=0.004). The levels of choline, betaine and dimethylglycine in plasma of MCDA twin pregnancy were significantly correlated with the birth weight and length of newborns (all P<0.05). Conclusion: Homocysteine level is associated with low birth weight in twins, methionine is associated with decreased risk of SGA, and choline is associated with fetal growth in the second and third trimesters of pregnancy.

Prenatal Diagnosis of Canine and Feline Twins Using Ultrasound: A Retrospective Study.

Prenatal diagnosis comprises a set of investigations, both instrumental and laboratory-based, which aim to monitor the health of the foetus during pregnancy, from the early stages of embryonic development to the moments preceding delivery. A growing interest is emerging for the preterm ultrasound morphological screening of embryos and foetuses, aimed at assessing the integrity and viability of the conceptus, as well as the early diagnosis of anomalies which can cause complications. This study is a retrospective study of the ultrasonographic findings of twins in the authors' clinical activity from 2016 to 2022. Only seven cases of monochorionic twins were recorded, out of the whole number of evaluations performed on 3120 foetuses, with a prevalence of 0.6% and 0.2% in feline and canine foetuses. All the twins had their own amniotic sac and umbilical cord but presented a single placenta and a single allantoic sac. Unfortunately, the three feline cases were not more recognizable at term. In the four canine cases, three were of opposite sex and then necessarily dizygotic. Twins may have an impact on the success of a pregnancy due to the risk of dystocia, as observed in some of the reported cases. Prenatal ultrasound allows early recognition of twins in dogs and cats.

Thick artery–artery anastomoses delay the onset of selective fetal growth restriction in monochorionic diamniotic twins: a 7-year single-center cohort study

ObjectiveThis study aimed to investigate differences in placental characteristics between early- and late-onset selective fetal growth restriction (sFGR) in monochorionic diamniotic twins.MethodsA total of 253 patients with sFGR between April 2013 and April 2020 were retrospectively analyzed. Placental characteristics of early- and late-onset sFGR were compared.ResultsThe gestational age at diagnosis and delivery in the early-onset group was significantly less than that in the late-onset group [22.0 (16.9–23.9) and 28.4 (24.0, 36.3) weeks, P &amp;lt; 0.001; 33.1 ± 2.2 and 33.7 ± 2.5 weeks, P = 0.025]. The birth weight of normal growth and growth-restricted fetuses in the early-onset group was less than the late-onset group [1,990 ± 422 and 2,162 ± 525 g, P = 0.044; 1,320 ± 409 and 1,595 ± 519 g, P = 0.001]. The birthweight discordance ratio in the early-onset group was greater than the late-onset group (0.34 ± 0.12 and 0.29 ± 0.13, P = 0.001). The early-onset group had a significantly lower prevalence of sFGR type I than the late-onset group (37.5 and 62.0%, P = 0.018). The early-onset group had a significantly higher prevalence of sFGR type III than the late-onset group (30.4 and 12.7%, P = 0.048). The early-onset group had a lower prevalence of thick artery–artery anastomoses than the late-onset group (37.5 and 62.0%, P = 0.006). The placental territory discordance ratio in the early-onset group was higher than in the late-onset group [0.60 (0.01, 0.80) and 0.50 (0.01, 0.88), P = 0.018].ConclusionUnequal placental territory is the cause for most of the late-onset sFGR. Thick artery–artery anastomoses may delay the onset time of these cases of sFGR.

Intertwin nuchal translucency difference predicts the chance of co-twin death after fetal reduction in dichorionic triplet pregnancies: a retrospective analysis study

ObjectivesTo compare the clinical outcomes of different multifetal pregnancy reduction (MFPR) programs in dichorionic (DC) triplets, and explore the association between early ultrasound characteristics and co-twin death after potassium chloride (KCl) injection into one monochorionic (MC) twin.MethodsWe retrospectively reviewed the data of DC triplets who underwent MFPR at our center during 2012–2021. Patients were grouped as follows: intracardiac KCl injection into one MC twin (group A), intracardiac KCl injection into both MC twins simultaneously (group B), and reduction of the singleton fetus (group C) and pregnancy outcomes were compared. Logistic regression was used to determine whether ultrasound measurements at 11–13+6 weeks predicted co-twin death and the receiver operator characteristic (ROC) analysis was conducted to assess the predictive performance.ResultsFinally, we enrolled 184 patients. 153 cases were in group A, and 18, 13 cases were in group B and C respectively. Gestational age at the time of MFPR did not differ among the 3 groups (median: 12^frac67 weeks). The survival rate was 89.6%, 88.9%, and 92.3% in group A, B, and C respectively, which was comparable among groups. Preterm birth was more common in group C (10/12, 83.3%). After KCl injection into one MC twin, co-twin death occurred in 86.3% cases (132/153) within 1 day; however, 3 patients had 2 live births each, with normal postnatal development. Intertwin nuchal translucency (NT) difference/discordance significantly predicted co-twin death within 1 day after MFPR, and the areas under the ROC curve were 0.694 and 0.689, respectively.ConclusionsFor MFPR in DC triplet pregnancies, reduction of the MC twins results in less preterm birth, and women with KCl injection into either one or both MC twins had similar outcomes. Large intertwin NT difference/discordance was associated with co-twin death within 1 day after KCl injection into one of the MC twins.

The impact of placental anastomoses and umbilical cord insertions’ sites on monochorionic twin pregnancy outcomes: Evidence from color-dye injection studies

IntroductionOur knowledge of monochorionic pregnancies’ complications is largely based on the extensive ongoing research on monochorionic placental structure. Previous studies on the concordance of umbilical cord insertions are limited. This study aimed to evaluate placental anastomoses and cord insertions as independent risk factors for neonatal adverse outcomes. MethodsThis was a prospective study conducted at Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy from April 2021 to December 2022. Seventy-six women with a monochorionic pregnancy were enrolled at their first-trimester scan. After delivery, all placentas that were confirmed to be monochorionic were analyzed according to standard protocols, including those of complicated monochorionic twin pregnancies. The primary outcomes were a Composite Monochorionic Pregnancy Outcome (CMPO) and a Composite Neonatal Adverse Outcome (CNAO). The secondary outcome was the birth weight discordance between the neonates. ResultsThe CMPO occurred in 15.8 % pregnancies, and the CNAO occurred in 67.1 % pregnancies. The analysis confirmed a significant association between velamentous cord insertions and neonatal adverse events (p = 0.003). Also, a significant positive association (p = 0.0326) between twin birth weight discordance and discordance in twins umbilical cord insertions’ sites was found. No significant association between the number and type of the anastomoses and both the CMPO or CNAO was detected. DiscussionOur data suggest that the routine sonographic assessment of umbilical cords' insertion sites during the first trimester could be helpful in predicting fetal and neonatal adverse events. We believe that this sonographic assessment should start to be implemented in our routine care of monochorionic pregnancies.