Mortality In Twin Pregnancies Research Articles

Study protocol for two randomised controlled trials evaluating the effects of Cerclage in the reduction of extreme preterm birth and perinatal mortality in twin pregnancies with a short cervix or dilatation: the TWIN Cerclage studies

IntroductionTwin pregnancies have a high risk of extreme preterm birth (PTB) at less than 28 weeks of gestation, which is associated with increased risk of neonatal morbidity and mortality. Currently...

Exposure to heavy metals and trace elements among pregnant women with twins: levels and association with twin growth discordance.

Twin growth discordance is one of the leading causes of perinatal mortality in twin pregnancies. Whether prenatal exposure to heavy metals and trace elements is associated with twin growth discordance has not been studied yet. To evaluate the prenatal level of heavy metals and trace elements in twin pregnancy and its relationship with twin growth discordance. This study involving 60 twin pairs and their mothers was conducted in Zhejiang Province, China, in 2020-2021. The concentration of heavy metals and trace elements in maternal blood, umbilical cord, and placenta were collected at delivery and measured by inductively coupled plasma tandem mass spectrometer. The association of prenatal level with twin growth discordance was evaluated using conditional logistic regression. High levels of heavy metal elements (thallium in maternal blood and umbilical cord blood of larger twins, vanadium in the placenta of larger twins) and trace elements (iodine in the placenta of larger twins) during pregnancy, as well as low levels of heavy metal elements (strontium in the umbilical cord blood of larger twins, strontium and chromium in the umbilical cord blood of smaller twins, strontium in the placenta of larger twins, molybdenum and lead in the placenta of smaller twins and difference of molybdenum in the placenta of twins), are associated with intertwin birthweight discordance. Univariate regression analyses showed a significant effect of gestational age at delivery and eleven trace element data on intertwin birthweight discordance. Multivariable logistic regression analysis with transformed variables as dichotomous risk factors combined with baseline demographic characteristics showed Tl in maternal blood as an independent risk factor. The model constructed by combining Tl in maternal blood (OR = 54.833, 95% CI, 3.839-83.156) with the gestational week (OR = 0.618, 95% CI, 0.463-0.824) had good predictive power for intertwin birthweight discordance (AUC = 0.871). The sensitivity analysis results indicate that the effect of maternal blood thallium on intertwin birthweight discordance is stable and reliable. To our knowledge, ours is the first case-control study to investigate the association between elevated maternal thallium levels before delivery and twin growth discordance.

Evaluating antenatal risk in twin pregnancies-A feasibility study to identify modifiable factors associated with adverse pregnancy outcomes.

Twin pregnancies have significantly higher rates of perinatal morbidity and mortality compared to singleton pregnancies; current attempts to reduce perinatal mortality have been less successful in twin pregnancies. The paucity of information about modifiable risk factors for adverse neonatal outcomes in twin pregnancies, as well as independent effects of chorionicity may have contributed to this outcome. This study aimed to explore the feasibility of an observational study to identify modifiable factors associated with adverse neonatal outcomes in twin pregnancies. Patients pregnant with twins at six UK hospitals between December 2019-March 2021 completed researcher-administered questionnaires at approximately 20-, 28- and 36-weeks' gestation, recording a wide range of self-reported social, lifestyle and demographic factors, alongside prospectively recorded clinical data from maternity records. Descriptive statistics were used to describe frequencies of exposures; logistic regression was used to determine whether factors were associated with a composite measure of adverse neonatal outcome. Data were collected from 65% (181/277) of eligible participants. A total of 98% (175) of participants had positive views about their participation. Some exposures, including cigarette smoking, supine sleep position and reduced fetal movements were less frequent in twin pregnancies compared to singletons, whereas fertility treatment was more common. Furthermore, different patterns of exposure were seen between monochorionic and dichorionic twins. This pilot study found some associations with adverse neonatal outcomes including: low BMI (OR 8.36, 95% CI: 1.02-68.87), maternal age ≥41 years (OR 9.0 95% CI: 1.07-75.84), maternally perceived high-stress levels (OR 1.96, 95% CI: 1.03-3.75) and inadequate antenatal screening (OR 1.44, 95% CI: 1.01-2.06). Sleep duration ≥9 h and right-sided going to sleep position were more frequent among pregnancies with adverse outcomes. Participants who reported receiving no information on fetal movement and reduced maternal perception of movements were more likely to have an adverse outcome, but sample size prohibited analysis based upon chorionicity. An observational study of modifiable factors in twin pregnancy is feasible. Differences in the frequencies of exposures between twin and singleton pregnancies highlight the need for twin-specific studies to identify modifiable factors and develop preventative strategies for morbidity and mortality in twin pregnancies.

Factors associated with perinatal mortality in twin pregnancies

Factors associated with perinatal mortality in twin pregnancies

Risk of severe acute maternal morbidity according to gestational age at delivery in twin pregnancies

Gestational age at delivery minimizing fetal and neonatal mortality in twin pregnancies seems to be 37 weeks of gestation. Our objective was to assess the so far unexplored association between gestational age at delivery and severe acute maternal morbidity (SAMM) in women with twin pregnancies.

Ultrasound in the prediction of birthweight discordance in dichorionic twins.

Large birthweight discrepancy has been identified as a risk factor for perinatal morbidity and mortality in twin pregnancies. However, it remains unclear whether such discordance can be predicted by various biological indices with specific cut-off values, and how these depend on the gestational age. We aimed to determine the most effective way to predict large birthweight discordance at various gestational ages. A retrospective cohort study of dichorionic twins, live-born between 2008 and 2018, was conducted. Discordances in biparietal diameter, head circumference, humerus and femur length, abdominal circumference, and estimated fetal weight were calculated-([larger twin-smaller twin]/larger twin)×100%-and compared between those with and without a large birthweight discordance (≥20%). Receiver operating characteristic curves were constructed to analyze the predictive characteristics of each parameter. Of 598 dichorionic twin pregnancies included, 83 (13.9%) had a birthweight discordance ≥20%. Group differences in biparietal diameter and head circumference discordance were the earliest to emerge (before 20weeks of gestation), but became insignificant after 36weeks, followed by humerus and femur length, estimated fetal weight discordance (after 20weeks), and abdominal circumference discordance (after 28weeks). The best predictors (with cut-off values) were discordance in biparietal diameter ≥7.8% at <20weeks, head circumference ≥4.5% at 20-23+6 weeks, humerus length ≥4.5% at 24-27+6 weeks, and estimated fetal weight discordance (≥11.6% at 28-31+6 weeks, ≥10.5% at 32-35+6 weeks, and ≥15.0% ≥36weeks), with sensitivity and specificity of 52%-77% and 69%-82%, respectively. Different predictors and cut-off values may be useful for predicting large inter-twin birthweight discordance in dichorionic twins at different gestational ages. It is more accurate to use biparietal diameter and head circumference discordance in the early second trimester, humerus length discordance in the late second trimester, and estimated fetal weight discordance in the third trimester.

Perinatal outcomes in Finnish twins: a retrospective study

BackgroundTo establish the changes in perinatal morbidity and mortality in twin pregnancies in Finland, a retrospective register research was conducted. Our extensive data from a 28-year study period provide important information on the outcome of twin pregnancies in Finland that has previously not been reported to this extent.MethodsAll 23,498 twin pregnancies with 46,996 children born in Finland during 1987–2014 were included in the study. Data were gathered from the Medical Birth Register and the Hospital Discharge Register (Finnish Institute for Health and Welfare, Finland) regarding perinatal mortality (PNM) and morbidity. For statistical analysis, binomial regression analysis and crosstabs were performed. The results are expressed in means, percentages and ranges with comparison to singletons when appropriate. Odds ratios from binomial regression analysis are reported. A p-value <0.05 was considered statistically significant.ResultsThere were 46,363 liveborn and 633 stillborn twins in Finland during 1987–2014. Perinatal mortality decreased markedly, from 45.1 to 6.5 per 1000 for twin A and from 54.1 to 11.9 per 1000 for twin B during the study period. Yet, the PNM difference between twin A and B remained. Early neonatal mortality did not differ between twins, but has decreased in both. Asphyxia, respiratory distress syndrome, need for antibiotics and Neonatal Intensive Care Unit (NICU) stay were markedly more common in twin B.ConclusionsIn Finland, PNM and early neonatal mortality in twins decreased significantly during 1987–2014 and are nowadays very low. However, twin B still faces more complications. The outline provided may be used to further improve the monitoring and thus perinatal outcome of twins, especially twin B.

Twin growth discordance in association with maternal exposure to fine particulate matter and its chemical constituents during late pregnancy

BackgroundTwin growth discordance is one of the leading causes of perinatal mortality in twin pregnancies. Whether prenatal exposure to fine particle (PM2.5) air pollution is associated with twin growth discordance have not been studied yet. ObjectiveTo evaluate the associations of prenatal exposure to PM2.5 and its chemical constituents with twin growth discordance. MethodsThis study included 1917 twin pairs and their mothers drawn from a previous twin birth cohort at the Shanghai First Maternity and Infant hospital in Shanghai, China. Exposure to PM2.5 total mass and 6 key chemical constituents during the whole pregnancy and each trimester of pregnancy was represented by satellite-based models. ResultsMaternal exposures to PM2.5 total mass and chemical constituents of sulfate (SO42−) and ammonium (NH4+) during the third trimester were significantly associated with increased within-pair birth weight difference and intertwin birth weight discordance. The within-pair birth weight difference increased by 30.6 g (β = 30.6, 95% CI, 4.4–56.9), 19.2 g (β = 19.2, 95% CI, 0.2–38.1) and 33.2 g (β = 33.2, 95% CI, 7.9–58.6) for an IQR increase in PM2.5 total mass, SO42− and NH4+ exposure, respectively. While the intertwin birth weight discordance increased by 1.3% (β = 1.3, 95% CI, 0.3–2.2), 0.9% (β = 0.9, 95% CI, 0.2–1.6) and 1.4% (β = 1.4, 95% CI, 0.4–2.3) for the same exposure metrics. Moreover, higher SO42− and NH4+ exposure was also associated with increased risk of twin growth discordance in linear dose-response manners. Compared to the lowest quartile of SO42− (OR = 2.51, 95% CI, 1.08–5.82) and NH4+ (OR = 2.97, 95% CI, 1.16–7.58) exposure, the odds of twin growth discordance were doubled in highest quartile of exposure. ConclusionOur results suggest that fine particle air pollution may be a risk factor for twin growth discordance. Late pregnancy seems to be a critical window for the effects of PM2.5 exposure on fetal growth in twins.

Weight discordance and perinatal mortality in twin pregnancy: systematic review and meta-analysis.

The primary aim of this systematic review was to explore the strength of association between birth-weight (BW) discordance and perinatal mortality in twin pregnancy. The secondary aim was to ascertain the contribution of gestational age and growth restriction in predicting mortality in growth-discordant twins. MEDLINE, EMBASE, CINAHL and ClinicalTrials.gov databases were searched. Only studies reporting on the risk of mortality in twin pregnancies affected compared with those not affected by BW discordance were included. The primary outcomes explored were incidence of intrauterine death (IUD), neonatal death (NND) and perinatal death. Outcome was assessed separately for monochorionic (MC) and dichorionic (DC) twin pregnancies. Analyses were stratified according to BW discordance cut-off (≥ 15%, ≥ 20%, ≥ 25% and ≥ 30%) and selected gestational characteristics, including incidence of IUD or NND before and after 34 weeks' gestation, presence of at least one small-for-gestational age (SGA) fetus in the twin pair and both twins being appropriate-for-gestational age. Risk of mortality in the larger vs smaller twin was also assessed. Meta-analyses using individual data random-effects logistic regression and meta-analyses of proportion were used to analyze the data. Twenty-two studies (10 877 twin pregnancies) were included in the analysis. In DC pregnancies, a higher risk of IUD, but not of NND, was observed in twins with BW discordance ≥ 15% (odds ratio (OR) 9.8, 95% CI, 3.9-29.4), ≥ 20% (OR 7.0, 95% CI, 4.15-11.8), ≥ 25% (OR 17.4, 95% CI, 8.3-36.7) and ≥ 30% (OR 22.9, 95% CI, 10.2-51.6) compared with those without weight discordance. For each cut-off of BW discordance explored in DC pregnancies, the smaller twin was at higher risk of mortality compared with the larger one. In MC twin pregnancies, excluding cases affected by twin-twin transfusion syndrome, twins with BW discordance ≥ 20% (OR 2.8, 95% CI, 1.3-5.8) or ≥ 25% (OR 3.2, 95% CI, 1.5-6.7) were at higher risk of IUD, compared with controls. MC pregnancies with ≥ 25% weight discordance were also at increased risk of NND (OR 4.66, 95% CI, 1.8-12.4) compared with those with concordant weight. The risk of IUD was higher when considering discordant pregnancies involving at least one SGA fetus. The overall risk of mortality in MC pregnancies was similar between the smaller and larger twin, except in those with BW discordance ≥ 20%. DC and MC twin pregnancies discordant for fetal growth are at higher risk of IUD but not of NND compared with pregnancies with concordant BW. The risk of IUD in BW-discordant DC and MC twins is higher when at least one fetus is SGA. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Early neonatal mortality in twin pregnancy: Findings from 60 low- and middle-income countries.

BackgroundAround the world, the incidence of multiple pregnancies reaches its peak in the Central African countries and often represents an increased risk of death for women and children because of higher rates of obstetrical complications and poor management skills in those countries. We sought to assess the association between twins and early neonatal mortality compared with singleton pregnancies. We also assessed the role of skilled birth attendant and mode of delivery on early neonatal mortality in twin pregnancies.MethodsWe conducted a secondary analysis of individual level data from 60 nationally-representative Demographic and Health Surveys including 521 867 singleton and 14 312 twin births. We investigated the occurrence of deaths within the first week of life in twins compared to singletons and the effect of place and attendance at birth; also, the role of caesarean sections against vaginal births was examined, globally and after countries stratification per caesarean sections rates. A multi-level logistic regression was used accounting for homogeneity within country, and homogeneity within twin pairs.ResultsEarly neonatal mortality among twins was significantly higher when compared to singleton neonates (adjusted odds ratio (aOR) 7.6; 95% confidence interval (CI) = 7.0-8.3) in these 60 countries. Early neonatal mortality was also higher among twins than singletons when adjusting for birth weight in a subgroup analysis of those countries with data on birth weight (n = 20; less than 20% of missing values) (aOR = 2.8; 95% CI = 2.2-3.5). For countries with high rates (>15%) of caesarean sections (CS), twins delivered vaginally in health facility had a statistically significant (aOR = 4.8; 95% CI = 2.4-9.4) increased risk of early neonatal mortality compared to twins delivered through caesarean sections. Home twin births without SBA was associated with increased mortality compared with delivering at home with SBA (aOR = 1.3; 95% CI = 1.0-1.8) and with vaginal birth in health facility (aOR = 1.7; 95% CI = 1.4-2.0).ConclusionsInstitutional deliveries and increased access of caesarian sections may be considered for twin pregnancies in low- and middle- income countries to decrease early adverse neonatal outcomes.

Perinatal morbidity and mortality in twin pregnancies in a Moroccan level-3 maternity ward

IntroductionLes grossesses gémellaires sont associées à un risque de morbimortalité périnatale plus élevé que les grossesses simples. Le but de cette étude était d’évaluer la morbimortalité périnatale dans les grossesses gémellaires dans une maternité marocaine de niveau 3.MéthodesIl s'agit d'une étude transversale comparative de la morbimortalité périnatale des nouveau-nés issus de grossesses gémellaires versus grossesses simples ayant accouché à la maternité Souissi de Rabat du 1 janvier au 28 février 2014.RésultatsIl y a eu 3297 naissances issues de 65 grossesses gémellaires et 3167 grossesses simples. Les grossesses gémellaires étaient associées à des taux plus élevés de prééclampsie et d’éclampsie (P = 0,046), de HELLP syndrome (P= 0,030), de rupture prématurée des membranes (P < 0,001), de présentation dystocique (P < 0,001), de prématurité (P < 0,001), d'hypotrophie chez les nouveau-nés à terme (P < 0,001), de détresse respiratoire néonatale (P < 0,001), de malformations congénitales (P = 0,015), d'hospitalisation en période néonatale (P = 0,001) et de mortalité périnatale (P = 0,001) par rapport aux grossesses simples. Les jumeaux monochoriaux présentaient des taux plus élevés d'hypotrophie en cas de grossesse menée à terme (P = 0,016) et de mortalité périnatale (P = 0,017) par rapport aux jumeaux bichoriaux.ConclusionLes grossesses gémellaires étaient à risque plus élevé de morbimortalité périnatale par rapport aux grossesses simples en exposant notamment à la prématurité. Les grossesses gémellaires monochoriales étaient plus à risque en exposant notamment à l'hypotrophie chez les nouveau-nés à terme.

Improved Perinatal Mortality in Twins--Changing Practice and Technologies.

We set out to examine rates of perinatal mortality in twin pregnancies over a 17-year study period. Changes in mode of delivery were also examined as well as causes of death in twin mortalities. This retrospective cohort study was performed at three large tertiary referral centers from 1996 to 2012. It included all normally formed twin infants with a birth weight more than 500 g. All cases of perinatal mortality in twin pregnancies (infants more than 500 g who suffered an intrauterine or early neonatal (≤ 7 days of age) death were recorded. The changing rate of cesarean delivery as well as varying causes of death in twins over the course of the study were also examined. During the study period, there were 395,830 pregnancies across the three institutions, this included 6,727 twin gestations. The perinatal mortality rate was 21.5/1,000 twin infants. The perinatal mortality rate in twins decreased over the study period (p = 0.0006; R (2) = 0.55; slope = -1.2). Rates of cesarean delivery in twin gestations were found to have increased over the course of the study (p < 0.0001; R (2) = 0.84; slope = 1.7). There were 288 intrauterine and early neonatal deaths in twin infants, 50% (147/288) occurred in twins born extremely premature (< 26 weeks). Prematurity was the leading cause of mortality in twins, followed by twin-to-twin transfusion syndrome (TTTS). TTTS was found to have a decreasing contribution to perinatal mortality during the study (p = 0.008; R (2) = 0.38; slope = -1.5). The perinatal mortality rate in twins improved during the study. The rate of cesarean delivery increased by 1.7% for each year of the study, culminating in a cesarean delivery rate of 62% in 2012. TTTS made a decreasing contribution to the mortality rate in twins during the study.

Infant mortality in twin pregnancies following in-utero demise of the co-twin

Abstract Objective To assess whether conversion from twin to singleton pregnancy following the demise of a co-twin influences survival. Methods This retrospective study compared the risk for neonatal, post-neonatal and infant death for converted co-twins versus unconverted co-twins using the US matched multiple file dataset for the period 1995–2000. We also examined the same risks for converted versus same-quantile co-twins, hazard ratios (HR) and 95% confidence intervals (CI) were computed using Cox Proportional Hazards models. Results The risk for neonatal (HR = 0.18, 95% CI: 0.09–0.34 and HR = 0.69, 95% CI: 0.50–0.96) and infant death (HR = 0.22, 95% CI: 0.12–0.42 and HR = 0.57, 95% CI: 0.42–0.77) were significantly lower for converted twins than for unconverted twins and same-quantile twins, respectively. For black compared to white, the risk for post-neonatal death increased by 89% (HR = 1.89, 95% CI = 1.03, 3.48), and 79% (HR = 1.79, 95% CI = 1.53, 2.09) for converted vs. unconverted and converted vs. same-quantile, respectively. For converted black, the risk for neonatal death decreased by 17% (HR = 0.83, 95% CI = 0.73–0.93) as compared to unconverted. Conclusions Risks for all mortality types were lower among converted co-twins than their unconverted or same-quantile counterparts. The lower neonatal and higher post-neonatal mortality among black require future research.

Is gestational hypertension protective against perinatal mortality in twin pregnancies?

BackgroundPregnancy-induced or gestational hypertension is a common pregnancy complication. Paradoxically, gestational hypertension has been associated with a protective effect against perinatal mortality in twin pregnancies in analytic models (logistic regression) without accounting for survival time. Whether this effect is real remains uncertain. This study aimed to validate the impact of gestational hypertension on perinatal mortality in twin pregnancies using a survival analysis approach.MethodsThis was a retrospective cohort study of 278,821 twin pregnancies, using the U.S. 1995–2000 matched multiple birth dataset (the largest dataset available for multiple births). Cox proportional hazard models were applied to estimate the adjusted hazard ratios (aHR) of perinatal death (stillbirth and neonatal death) comparing gestational hypertensive vs. non-hypertensive pregnancies controlling for maternal characteristics and twin cluster-level dependence.ResultsComparing births in gestational hypertensive vs. non-hypertensive twin pregnancies, perinatal mortality rates were significantly lower (1.20% vs. 3.38%), so were neonatal mortality (0.72% vs. 2.30%) and stillbirth (0.48% vs. 1.10%) rates. The aHRs (95% confidence intervals) were 0.34 (0.31–0.38) for perinatal death, 0.31 (0.27–0.34) for neonatal death, and 0.45 (0.38–0.53) for stillbirth, respectively. The protective effect of gestational hypertension against perinatal death became weaker over advancing gestational age; the aHRs in very preterm (<32 weeks), mild preterm (32–36 weeks) and term (37+ weeks) births were 0.29, 0.48 and 0.76, respectively. The largest risk reductions in neonatal mortality were observed for infections and immaturity-related conditions.ConclusionsGestational hypertension appears to be beneficial for fetal survival in twin pregnancies, especially in those ending more prematurely or for deaths due to infections and immaturity-related conditions. Prospective studies are required to rule out the possibility of unmeasured confounders.

Diabetes and Perinatal Mortality in Twin Pregnancies

BackgroundDiabetes in pregnancy has been associated with a paradoxically reduced risk of neonatal death in twin pregnancies. Risk “shift” may be a concern in that the reduction in neonatal deaths may be due to an increase in fetal deaths (stillbirths). This study aimed to clarify the impact of diabetes on the risk of perinatal death (neonatal death plus stillbirth) in twin pregnancies.MethodsThis was a retrospective cohort study of twin births using the largest available dataset on twin births (the U.S. matched multiple birth data 1995-2000; 19,676 neonates from diabetic pregnancies, 541,481 from non-diabetic pregnancies). Cox proportional hazard models were applied to estimate the adjusted hazard ratios (aHR) of perinatal death accounting for twin cluster-level dependence.ResultsComparing diabetic versus non-diabetic twin pregnancies, overall perinatal mortality rate was counterintuitively lower [2.1% versus 3.3%, aHR 0.70 (95% confidence intervals 0.63-0.78)]. Individually, both stillbirth and neonatal mortality rates were lower in diabetic pregnancies, but we identified significant differences by gestational age and birth weight. Diabetes was associated with a survival benefit in pregnancies completed before 32 weeks [aHR 0.55 (0.48-0.63)] or with birth weight <1500 g [aHR 0.61 (0.53-0.69)]. In contrast, diabetes was associated with an elevated risk of perinatal death in pregnancies delivered between 32 and 36 weeks [aHR 1.38 (1.10-1.72)] or with birth weight >=2500 g [aHR 2.20 (1.55-3.13)].ConclusionsDiabetes in pregnancy appears to be “protective” against perinatal death in twin pregnancies ending in very preterm or very low birth weight births. Prospective studies are required to clarify whether these patterns of risk are real, or they are artifacts of unmeasured confounders. Additional data correlating these outcomes with the types of diabetes in pregnancy are also needed to distinguish the effects of pre-gestational vs. gestational diabetes.

Perinatal morbidity and early neonatal mortality in twin pregnancies

Purpose: The purpose of this study was to investigate the impact of maternal, fetal and obstetric parameters in twin pregnancies due to chorionicity, perinatal morbidity and early neonatal mortality. Methods: Early neonatal outcome parameters were retrospectively analysed in 240 twin pregnancies (51 monochorionic [MC], 189 dichorionic [DC] twins) over a 7.5 years period. Beside chorionicity, we focused on risk factors affecting perinatal morbidity and early neonatal outcome in the overall study cohort and subgroups 1) late preterm and 2) pregnancies conceived by artificial fertilization (IVF/ICSI). Mixed effects logistic regression models were used for multivariate risk analyses. Results: MC vs DC pregnancies showed significantly lower birth weights (p 25% and amniotic inflammation (amniotic infection syndrome [AIS]). A gestational age >36 completed weeks was accompanied by a decrease of early neonatal complications (p

Influence of chorionicity in intra-partum management of twin deliveries

Objective: To analyze morbidity and mortality in twin pregnancies as a function of the type of delivery and chorionicity. Design: Retrospective cohort study. Methods: Analysis of the type of delivery, intertwin time interval, and perinatal variables of >1000 twin deliveries during a 10-year period. Main outcome measure: Influence of delivery type and chorionicity on perinatal outcome. Results: The rate of cesarean sections was 42.4%. No differences were found as a function of chorionicity or as a function of presentation of the second twin. Cesarean sections were performed after vaginal delivery of the first twin in 1.8% of cases, being more common if the second baby was in a non-cephalic presentation (6.9% vs. 0.4%, p < 0.05). The average twin-to-twin delivery time interval was longer in the cases where the second had a cephalic presentation (8.26 ± 7.75 min vs. 6.81 ± 5.97 min, p < 0.05). The umbilical artery pH was lower the longer the interval between the birth of the twins, both in monochorionic and dichorionic. Conclusions: According to the results, vaginal delivery is as safe as elective caesarean section in twin pregnancies where the first twin is in cephalic presentation and the intrapartum management should not vary due to chorionicity.

Complicaciones del embarazo gemelar monocorial: claves para el diagnóstico y tratamiento

Monochorionic twin pregnancy (MC) occurs in one in 250 pregnancies and represents a significant proportion of perinatal morbidity and mortality in twin pregnancies, and in general. The optimal management of MC is based on two fundamental aspects: early classification of chorionicity and close monitoring. The differential diagnosis of the complications of MC is still a challenge to the fetal medicine specialist. This is due to the frequent overlap of clinical signs and the complex relationships between the potential complications. However, the differential diagnosis and subsequent decisions are based on relatively simple rules. While some cases can be really complicated, clinical experience shows that in most cases proper classification and management can be achieved through the consistent use of simple concepts. This review provides an overview that allows a comprehensive understanding of MC twin pregnancies, the typical complications and the key concepts that allow an appropriate differential diagnosis and specific management.

Perinatal morbidity and mortality in twin pregnancies with dichorionic placentas following assisted reproductive techniques or ovarian induction alone: a comparative study

Objective To compare maternal and perinatal outcome in non-spontaneously and spontaneously conceived dichorionic twin pregnancies. Study design We report a retrospective study of all 350 twin pregnancies delivered ≥22 weeks of gestation between January 1, 2001 and December 31, 2005 in a tertiary maternity unit. We compared maternal outcome, perinatal morbidity and neonatal mortality between spontaneous and non-spontaneous dichorionic twin pregnancies, with a subgroup analysis separating pregnancies following assisted reproduction technology (ART group) from those following ovarian induction alone (OI group). Generalized linear model and multivariate analysis were performed. Results The proportion of primiparous women and the mean maternal age were higher in the non-spontaneously conceived dichorionic twin pregnancy group as expected (70.2% vs. 38.2%, p < 0.001 and 32.1 ± 3.8 vs. 30.7 ± 4.6 years, p < 0.01). Multivariate analysis, adjusted for maternal age and parity, revealed that non-spontaneously conceived dichorionic twin pregnancies were associated with a higher risk of very preterm birth (OR 2.20, 95% confidence interval 1.02–4.77, p < 0.05), low birth weight (1.77, 1.21–2.61, p < 0.01), very low birth weight (1.99, 1.13–3.49, p < 0.05), NICU admission (1.66, 1.14–2.43, p < 0.01), and fetal or neonatal death (3.21, 1.30–7.95, p < 0.05). Multivariate analysis confirmed that the mean gestational age ( p < 0.01) and mean birth weight of the first ( p < 0.05) and second twins ( p < 0.01) were lower in the non-spontaneously conceived dichorionic twin pregnancy group. These associations were confirmed in the OI group analysis ( n = 39) but not in the ART group ( n = 65). Ovarian induction was associated with an increase in the risk of preterm and very preterm births (2.25, 1.06–4.75, p < 0.05 and 3.47, 1.42–8.49, p < 0.01, respectively), low and very low birth weights (2.87, 1.63–5.05, p < 0.001 and 2.59, 1.33–5.07, p < 0.01, respectively), NICU admission (2.92, 1.67–5.11, p < 0.001) and fetal or neonatal death (4.20, 1.40–12.56, p < 0.05). The mean gestational age ( p < 0.001) and mean birth weight of the first ( p < 0.01) and second twins ( p < 0.001) were also lower in the OI group. Conclusions Twin pregnancies with dichorionic placentation following non-spontaneously conceived pregnancy are associated with a higher risk of adverse perinatal outcome compared with dichorionic spontaneously conceived twin pregnancies especially in case of ovarian induction alone.

Early neonatal morbidity and mortality in growth‐discordant twins

To evaluate early neonatal morbidity and mortality in twin pregnancies with growth discordance. Retrospective study. Tertiary teaching hospital, Sao Paulo, Brazil. A total of 151 twin pregnancies managed and delivered at the Multiple Pregnancy Unit at Sao Paulo University Hospital between 1998 and 2004. METHODS; Comparison between twin pregnancies with weight discordance > or =20% and pregnancies concordant for fetal weight. Cases with fetal death, abnormalities, twin-to-twin transfusion and delivery before 26 weeks or in another hospital were excluded. Early neonatal morbidity (Apgar at 5 minutes <7, respiratory or neurological complications, infection, necrotizing enterocolitis, length of hospital stay) and mortality. Forty (26.5%) pregnancies presented discordance > or =20% and 111 (73.5%) were concordant. In the discordant group, 75% of pregnancies had at least one growth restricted fetus (<10th centile). In concordant twin pregnancies, monochorionic cases (22.5%) presented with lower gestational age (34.3 vs. 36.2 weeks), lower birthweight (2,067 vs. 2,334 g) and a longer period of hospital stay (5.5 vs. 3.0) compared to dichorionic concordant twins. No differences between monochorionic and dichorionic subgroups were observed in discordant twins. Pregnancies in which at least one baby was born with a birthweight below the 10th centile showed that discordant pregnancies had a lower gestational age at delivery (35.2 vs. 36.8 weeks) and a longer period of hospital stay (9 vs. 4 weeks) compared to concordant cases. Neonatal mortality was similar in discordant (3.7%) and concordant (4.5%) twins. Early perinatal morbidity is increased in twin pregnancies with birthweight discordance > or =20% only when associated with fetal growth restriction and low birthweight.