Does risk of preeclampsia differ by twin chorionicity?

Impact factors and obstetric outcomes of preeclampsia in twin pregnancies by prepregnancy body mass index: a six-year retrospective cohort study

OBJECTIVES

Among many risk factors for preeclampsia (PE), prepregnancy body mass index (BMI) is one of few controllable factors. However, there is a lack of stratified analysis based on the prepregnancy BMI. This study aimed to determine the influencing factors for PE and assess the impact of PE on obstetric outcomes in twin pregnancies by prepregnancy BMI.

METHODS

This was a retrospective cohort study between January 1, 2017, and December 31, 2022, in Southwest China. Impact factors and associations between PE and obstetric outcomes were analyzed separately for twin pregnancies with prepregnancy BMI < 24kg/m2 (non-overweight group) and BMI ≥ 24kg/m2 (overweight group).

RESULTS

In total, 3602 twin pregnancies were included, of which, 672 women were allocated into the overweight group and 11.8% of them reported with PE; 2930 women were allocated into the non-overweight group, with a PE incidence of 5.6%. PE had a negative effect on birthweight and increased the incidence of neonatal intensive care unit admission in both the overweight and non-overweight groups (43.0% vs. 28.0%, p = .008; 45.7% vs. 29.1%, p < .001). Among overweight women, PE increased the proportion of postpartum hemorrhage (15.2% vs. 4.4%, p < .001). After adjustments, multivariate regression analysis showed that excessive gestational weight gain (aOR = 1.103, 95% CI: 1.056-1.152; aOR = 1.094, 95% CI: 1.064-1.126) and hypoproteinemia (aOR = 2.828, 95% CI: 1.501-5.330; aOR = 6.932, 95% CI: 4.819-9.971) were the shared risk factors for PE in both overweight and non-overweight groups. In overweight group, in vitro fertilization was the other risk factor (aOR = 2.713, 95% CI: 1.183-6.878), whereas dichorionic fertilization (aOR = 0.435, 95% CI: 0.193-0.976) and aspirin use during pregnancy (aOR = 0.456, 95% CI: 0.246-0.844) were protective factors. Additionally, anemia during pregnancy (aOR = 1.542, 95% CI: 1.090-2.180) and growth discordance in twins (aOR = 2.451, 95% CI: 1.215-4.205) were connected with an increased risk of PE only in non-overweight twin pregnancies.

CONCLUSIONS

Both discrepancy and similarity of impact factors on developing PE were found between overweight and non-overweight twin pregnancies in this study. However, the dosage and initiation time of aspirin, as well as twin chorionicity on the occurrence of PE in two subgroups, are still debated.

Egg donation and gestational surrogacy: Pregnancy is riskier with an unrelated embryo

Modern medicine has revolutionized family planning. Remarkably, women1 can carry to term embryos with whom they share no genetic connection, a feat made possible through egg donation and/or gestational surrogacy. Our reproductive systems evolved to accommodate embryos that are 50% related to the carrier, not 0% related. Here, we apply evolutionary theory to explain how and why pregnancy is riskier with an unrelated embryo. When a woman gestates an unrelated embryo, she is significantly more likely to develop preeclampsia and other diseases above and beyond the known risks associated with advanced maternal age, IVF, multiple gestation, and subfertility. Such "allogeneic pregnancies" are riskier even in fertile, healthy, commercial surrogates and when the egg is donated by a young, healthy donor. We propose that unrelated embryos present a special immune challenge to the gestational carrier, because they have fewer matching genes to the maternal body-therefore exacerbating symptoms of evolutionary maternal-fetal conflict. Indeed, maternal risks seem lower when the embryo is more related to the carrier, e.g., if a sister donates the egg. Finally, we discuss microchimerism in egg donation pregnancies, whereby wholly foreign cells pass from mother to embryo and vice-versa. We conclude with several medical proposals. First, egg donors and surrogates should be informed of the increased health risks they would face. In considerations of risk, these young, fertile women should not be compared to older, infertile women undergoing IVF; the proper comparison group is other young, fertile women. Second, contrary to some medical advice, perhaps genetically-related egg donors and surrogates should be preferred, all else equal. An immunological matching scheme, like what is used for organ transplants, could improve surrogate pregnancy outcomes. Third, more research is needed on microchimerism, sperm exposure, and the long-term impacts of allogeneic pregnancies on maternal and child health.

The Association of Twin Chorionicity with Maternal Outcomes

OBJECTIVE

Our objective was to investigate the association between maternal outcomes and twin chorionicity in a large, contemporary obstetric population.

STUDY DESIGN

Retrospective cohort study was conducted at a single, large tertiary care center. Prenatal and inpatient records for all individuals with twin gestations were reviewed from 2000 to 2016. Patients with monoamniotic twins, higher-order multiples reduced to twins, multiple sets of twins in the study period, or undetermined chorionicity were excluded. Patients with monochorionic twins were compared with those with dichorionic twins. The co-primary outcomes were gestational diabetes mellitus and hypertensive disorders of pregnancy. Secondary outcomes included cesarean delivery, preterm delivery, postpartum hemorrhage, and other maternal outcomes. Bivariate and multivariate analyses were performed to assess associations of chorionicity with maternal outcomes.

RESULTS

Of the 2,979 patients eligible for inclusion, 2,627 (88.2%) had dichorionic twin gestations and 352 (11.8%) had monochorionic twin gestations. Patients with monochorionic twins were less likely to self-identify as non-Hispanic White and to have conceived via assisted reproductive technology but were more likely to be publicly insured, multiparous and have prenatal care with a maternal-fetal medicine provider. Neither gestational diabetes mellitus (6.8% monochorionic vs. 6.2% dichorionic, p = 0.74; adjusted odds ratio [OR] 1.06, 95% confidence interval (CI) 0.60-1.86) nor hypertensive disorders of pregnancy (21.9% monochorionic vs. 26.3% dichorionic, p = 0.09; adjusted OR 0.99, 95% CI, 0.71-1.38) differed by chorionicity. Of the secondary maternal outcomes, patients with monochorionic twins experienced a lower frequency of cesarean delivery (46.0 vs. 61.8%, p < 0.001), which persisted after multivariate analyses (adjusted OR 0.60, 95% CI 0.46-0.80). There were no differences in preterm delivery, preterm premature rupture of membranes, hemorrhage, hysterectomy, or intrahepatic cholestasis of pregnancy.

CONCLUSION

The odds of gestational diabetes mellitus and hypertensive disorders of pregnancy do not appear to differ by twin chorionicity.

KEY POINTS

· Hypertensive disorders of pregnancy do not differ by twin chorionicity.. · Gestational diabetes mellitus does not differ by twin chorionicity.. · Maternal outcomes are similar for individuals with monochorionic and dichorionic twin gestations..

Maternal plasma angiotensin 1-7 concentration is related to twin pregnancy chorionicity in the third trimester of pregnancy

Introduction

Twin gestation is related to a higher risk of hypertensive disorders in pregnancy with possible risk stratification depending on chorionicity. It may be related to differences in plasma renin-angiotensin-aldosterone components between monochorionic and dichorionic twin pregnancies. The study aimed to analyze the plasma ANG II and ANG 1-7 concentrations in women with monochorionic and dichorionic twin gestation.

Methods

A prospective observational study included 79 women between 32 and 34 weeks of gestation with twin pregnancy (31 with monochorionic gestation and 48 with dichorionic gestation). Angiotensin II and angiotensin 1-7 concentrations were measured in the collected blood samples.

Results

No significant differences were observed in angiotensin II concentrations between the dichorionic and monochorionic group with significantly higher levels of angiotensin 1-7 being observed in the dichorionic group. Angiotensin 1-7 level was higher than angiotensin II in 20 women (64.5%) in the monochorionic group and in 42 women (87.5%, p=0.01) in the dichorionic group. Higher plasma concentrations of angiotensin II and lower concentrations of angiotensin 1-7 were found in 5 women with gestational hypertension and in 3 with preeclampsia compared to normotensive women.

Discussion

It is the first study investigating angiotensin II and angiotensin 1-7 in twin pregnancies regarding chorionicity. Our results showed that plasma angiotensin 1-7 concentration was related to chorionicity, while plasma angiotensin II level was not. In most women with twin gestation angiotensin 1-7 concentration exceeded the concentration of angiotensin II. A switch in the relation between angiotensin II and angiotensin 1-7 was observed in hypertensive pregnant women.

Twin charts should be the standard reference to assess growth in twin pregnancy

PURPOSE OF REVIEW

Twin pregnancies are characterized by slower growth velocity compared with singletons, especially during the third trimester and, therefore, tend to be smaller than singletons. Growth surveillance is instrumental in the identification of twin pregnancies at risk of adverse outcomes. Whether the phenomenon of slow growth is an adaptive physiological response or represents pathological growth lag, is controversial. In this review, we focus on the evidence related to the types of growth charts employed for twin pregnancies.

RECENT FINDINGS

Consistent evidence has emerged over the past few years from large independent cohorts in different countries suggesting that twin-specific standards perform better in identifying growth-restricted twin pregnancies at risk of adverse perinatal outcomes, without resulting in an increase in interventions or iatrogenic prematurity.

SUMMARY

The current evidence supports the use of twin-specific reference charts. Concerted efforts should be made to derive prospective evidence from large multicentre studies on various aspects of the implementation of twin-specific standards.

Intertwin growth discordance throughout gestation and hypertensive disorders of pregnancy

BACKGROUND

Previous studies have established the association between intertwin birthweight discordance and hypertensive disorders of pregnancy. However, longitudinal fetal size discordance concerning gestational hypertension or preeclampsia remains unclear.

OBJECTIVE

This study aimed to compare the patterns of estimated fetal weight discordance throughout gestation among normotensive women, women with gestational hypertension, and women with preeclampsia and to evaluate the association between crown-rump length discordance at 11 to 14 weeks of gestation and hypertensive disorders of pregnancy.

STUDY DESIGN

This was a retrospective cohort study of women with twin pregnancies who had antenatal care visits and delivered at a tertiary hospital between January 2013 and June 2021. The crown-rump length was measured at 11 to 14 weeks of gestation. Estimated fetal weight was calculated based on ultrasound examinations of fetal biometrics at 16 to 18, 20 to 24, 28 to 32, and ≥34 weeks of gestation, respectively. Crown-rump length and estimated fetal weight discordances were calculated: (larger crown-rump length - smaller crown-rump length)/larger crown-rump length × 100% and (larger estimated fetal weight - smaller estimated fetal weight)/larger estimated fetal weight × 100%, respectively. Multiple imputation was used to handle missing data, and all models accounted for the imputation. Multilevel model analysis was used to compare the differences in estimated fetal weight discordances throughout gestation among normotensive women, women with gestational hypertension, and women with preeclampsia. Generalized linear models were used to evaluate the association between crown-rump length discordance and hypertensive disorders of pregnancy, assuming a Poisson distribution. The possible nonlinear relationship between continuous crown-rump length discordance and hypertensive disorders of pregnancy was examined by generalized additive models. All analyses were stratified by chorionicity.

RESULTS

Of the 3280 women with twin pregnancies who met the inclusion criteria, 187 (5.7%) developed gestational hypertension, and 436 (13.3%) developed preeclampsia, including 125 (3.8%) early-onset preeclampsia and 311 (9.5%) late-onset preeclampsia. In women with dichorionic twin pregnancies, compared with normotensive women, a substantial progression of estimated fetal weight discordance throughout pregnancy was identified in women who developed preeclampsia, and a large progression of estimated fetal weight discordance in late pregnancy was identified in women who developed gestational hypertension. In women with monochorionic twin pregnancies, estimated fetal weight discordances were more progressive from 20 to 24 weeks of gestation onward in women who developed preeclampsia than in normotensive women. Crown-rump length discordance at 11 to 14 weeks of gestation was associated with an increased risk of preeclampsia (relative risk, 1.03; 95% confidence interval, 1.00-1.05), particularly early-onset preeclampsia (relative risk, 1.09; 95% confidence interval, 1.04-1.13). A crown-rump length discordance of ≥10% had 1.2 times the increased risk of developing early-onset preeclampsia (relative risk, 2.27; 95% confidence interval, 1.28-4.03). This association was identified in dichorionic twins, but not in monochorionic twins.

CONCLUSION

Our study demonstrated distinct growth discordant patterns among normotensive women, women with gestational hypertension, and women with preeclampsia in twin pregnancies. Intertwin crown-rump length discordance at 11 to 14 weeks of gestation was associated with an increased risk of preeclampsia, especially early-onset preeclampsia in dichorionic twin pregnancies, with a dose-response pattern.

Twin Growth Discordance and Risk of Postpartum Hemorrhage: A Retrospective Cohort Study

Background

In recent years, the incidence of postpartum hemorrhage has increased globally. Multiple pregnancies and cesarean sections are well-known risk factors for postpartum hemorrhage. No studies have evaluated the associations between fetal growth anomalies and postpartum hemorrhage in women with twin pregnancies undergoing cesarean section. This study aimed to identify the relationship between fetal growth anomalies and postpartum hemorrhage in women with twin pregnancies undergoing cesarean section.

Methods

This retrospective single-center study included 3,180 women with twin pregnancies at a tertiary hospital between August 2013 and July 2020. Singleton reference charts were used to assess fetal growth restriction at birth. Discordant growth was defined as an intertwin birth weight difference of ≥20%. Logistic regression analyses were used to evaluate the association between fetal growth anomalies and postpartum hemorrhage. Additionally, sensitivity analysis of abnormal placenta and stratification by twin chorionicity were conducted.

Results

The overall incidence of postpartum hemorrhage was 4.3%. Twin growth discordance, especially with fetal growth restriction, was associated with an increased risk of postpartum hemorrhage (adjusted odds ratio [AOR] = 1.62, 95% confidence interval [CI], 1.05-2.51, P = 0.031; AOR = 1.71; 95% CI, 1.08-2.70, P = 0.022; AOR = 1.98, 95% CI, 1.21-3.25, P = 0.006, respectively). After stratification, this relationship persisted in dichorionic twins (OR = 1.71, 95% CI, 1.04-2.82, P = 0.036; OR = 1.90, 95% CI, 1.13-3.21, P = 0.016; OR = 2.48, 95% CI, 1.41-4.38, P = 0.002, respectively). However, no significant association was observed in monochorionic twin pregnancies.

Conclusion

Growth discordance, especially complicated by fetal growth restriction, was associated with an increased risk of postpartum hemorrhage in women with twin pregnancies undergoing cesarean section, and was more evident in patients with dichorionic twins.

Screening for preeclampsia in twin pregnancies

Twin pregnancies are an important risk factor for preeclampsia, a hypertensive disorder of pregnancy that is associated with a significant risk of maternal and perinatal morbidity. Given the burden of preeclampsia, the identification of women at high risk in early pregnancy is essential to allow for preventive strategies and close monitoring. In singleton pregnancies, the risk factors for preeclampsia are well established, and a combined first-trimester prediction model has been shown to adequately predict preterm disease. Furthermore, intervention with low-dose aspirin at 150 mg/day in those identified as high-risk reduces the rate of preterm preeclampsia by 62%. In contrast, risk factors for preeclampsia in twin pregnancies are less established, the proposed screening models have shown poor performance with high false-positive rates, and the benefit of aspirin for the prevention of preeclampsia is not clearly demonstrated. In this review, we examine the literature assessing prediction and prevention of preeclampsia in twin pregnancies.

Incidence of chest X-ray abnormalities early in the third trimester of twin pregnancy and its relationship with the subsequent development of preeclampsia

AIM

To clarify the incidence of abnormal findings on chest X-ray (CXR) early in the third trimester of twin pregnancy and its relationship with the development of preeclampsia and preeclampsia-related diseases.

METHODS

This was a retrospective cohort study conducted among women with twin pregnancies who underwent chest radiography for preoperative screening early in the third trimester and delivered at our center at >34 weeks' gestation from 2013 to 2017. The primary outcome was the incidence of positive CXR findings, defined either as cardiomegaly or blunting of the costophrenic angle. The secondary outcome was the incidence of maternal complications, including preeclampsia; hemolytic, elevated liver enzymes, and low platelet syndrome; eclampsia; cerebrovascular disease; and placental abruption. We evaluated the significance of positive CXR findings, in addition to confounding factors, in the subsequent development of preeclampsia.

RESULTS

During the study period, 358 twin pregnancies were identified, and 330 were finally enrolled. The incidence of positive CXR findings was 18.2%. The incidence of preeclampsia in the CXR-positive group was 36.7% (22/60), which was significantly higher than that in the CXR-negative group (7.0% [19/270]) (p < 0.01). Moreover, positive CXR findings were independently associated with subsequent preeclampsia (adjusted odds ratio: 9.15, 95% confidence interval: 4.13-20.3).

CONCLUSION

In twin pregnancies, the incidence of CXR abnormalities early in the third trimester was 18.2%, even without the development of hypertension. This should be considered a significant risk factor for subsequent preeclampsia.

Risk Factors for Early and Late Onset Preeclampsia in Reunion Island: Multivariate Analysis of Singleton and Twin Pregnancies. A 20-Year Population-Based Cohort of 2120 Preeclampsia Cases

Objectives: To develop a multivariate model for risk factors specific to early onset preeclampsia (EOP) and late onset preeclampsia (LOP) in our entire population (singleton and twin pregnancies). Material and methods: 20 year-observational population-based historical cohort study (2001–2020). All consecutive births delivered at the Centre Hospitalier Universitaire Hospitalier Sud Reunion’s maternity ward. A standardized validated epidemiological perinatal database was used. Results: During the 20-year period, there were 81,834 pregnancies and 83,497 infants born, 1232 dichorionic and 350 monochorionic twin pregnancies. There were 2120 cases of preeclampsia, of which 2001 were preeclamptic singleton pregnancies and 119 twin pregnancies (incidence 7.5% in twin pregnancies vs. 2.5% singletons, OR 3.0, p < 0.001). Independent risk factors for EOP and LOP in a multivariate model (controlling for the two major confounders: maternal ages—both risks for EOP and LOP, and maternal pre-pregnancy BMI—specific risk factor for LOP) were: history of preeclampsia (adjusted OR (aOR) 11.7 for EOP, 7.8 for LOP, p < 0.0001), chronic hypertension (aOR 7.3 for EOP, 3.9 for LOP, p < 0.0001), history of perinatal death (aOR 2.2 for EOP, p < 0.0001 and 1.48 for LOP, p = 0.007), primipaternity (aOR 3.0 for EOP and 3.6 for LOP, p = 0.001), dizygotic twin pregnancies (aOR 3.7 for EOP, p < 0.0001 and 2.1 for LOP, p = 0.003), monozygotic twin pregnancies (aOR 3.98 for EOP, p = 0.003 and non-significant (NS) for LOP), ovulation induction (aOR 5.6 for EOP, p = 0.004 and NS for LOP), and in vitro fertilization (aOR 2.8 for EOP, p = 0.05 and NS for LOP). Specific to LOP and NS for EOP: renal diseases (aOR for LOP 2.9, p = 0.007) and gestational diabetes mellitus (aOR 1.2, p = 0.04). Conclusions: Maternal ages over 35 years, chronic hypertension, history of preeclampsia, ovulation induction, in vitro fertilizations, history of perinatal deaths and twin pregnancy (in our experience, especially mono zygotic twin pregnancies) are significant risk factors for EOP. New paternity is an independent factor for both EOP and LOP.

Women with multiple gestations have an increased risk of development of hypertension in the future

Background

Multiple gestations are associated with an increased incidence of preeclampsia. However, there exists no evidence for an association between multiple gestations and development of hypertension(HTN) later in life. This study aimed to determine whether multiple gestations are associated with HTN beyond the peripartum period.

Methods

In this retrospective nationwide population-based study, women who delivered a baby between January 1, 2007, and December 31, 2008, and underwent a national health screening examination within one year prior to their pregnancy were included. Subsequently, we tracked the occurrence of HTN during follow-up until December 31, 2015, using International Classification of Diseases-10th Revision codes.

Results

Among 362,821 women who gave birth during the study period, 4,944 (1.36%) women had multiple gestations. The cumulative incidence of HTN was higher in multiple gestations group compared with singleton group (5.95% vs. 3.78%, p < 0.01, respectively). On the Cox proportional hazards models, the risk of HTN was increased in women with multiple gestations (HR 1.35, 95% CI 1.19, 1.54) compared with those with singleton after adjustment for age, primiparity, preeclampsia, atrial fibrillation, body mass index, blood pressure, diabetes mellitus, high total cholesterol, abnormal liver function test, regular exercise, and smoking status.

Conclusions

Multiple gestations are associated with an increased risk of HTN later in life. Therefore, guidelines for the management of high-risk patients after delivery should be established.

sFlt-1, Not PlGF, Is Related to Twin Gestation Choronicity in the First and Third Trimesters of Pregnancy

Background: Preeclampsia occurs more often in dichorionic than in monochorionic twin pregnancy. We hypothesize that serum concentrations of biomarkers: placental growth factor (PlGF), serum soluble fms-like tyrosine kinase-1 (sFlt-1), and endoglin (Eng) differ between monochorionic and dichorionic twin pregnancies. Methods: A prospective observational study including 43 monochorionic and 36 dichorionic twin gestation was conducted. Blood samples were collected twice from all participants: between 11 + 0 and 13 + 6 and between 32 + 0 and 34 + 0 weeks of gestation. PlGF, sFlt-1 and Eng were measured using immnunoenzymatic assays. Results: We found a significantly higher concentration of sFlt-1 in dichorionic in comparison to monochorionic pregnancies in both the first and third trimesters. PlGF and sEng levels did not differ between mono- and dichorionic gestation in both study periods. sFlt-1 level was related to twin gestation chorionicity, while PlGF expression was not. PlGF, sFlt-1 and sEng concentrations increased significantly during gestation and were much higher in the third trimester compared to the values measured in the first trimester. Conclusions: Angiogenic biomarkers expression differ between dichorionic and monochorionic twin pregnancy. The sFlt-1 level is related to chorionicity of a twin gestation.

The influence of hypertensive disorders during pregnancy on the perinatal outcome of different chorionic twins

OBJECTIVE

To investigate the influence of hypertensive disorders of pregnancy (HDP) on the perinatal outcomes in twin pregnancies.

METHODS

This was a retrospective single-center study in which, 2160 twin pregnancies delivered between January 2016 and December 2019 were analyzed, 1661 of which were dichorionic (DC) and 499 monochorionic (MC). The perinatal outcomes were compared in 404 twin pregnancies with HDP, including 157 gestational hypertension (GH), 107 mild pre-eclampsia (MPE), 140 severe pre-eclampsia (SPE), and 1756 twins without hypertensive disorders of pregnancy (no-HDP). Multiple linear regression was performed to analyze the association between perinatal outcome and HDP. Stratified sampling by twin chorionicity (DC and MC) was also conducted.

RESULTS

There were 330 (19.9%) DC cases complicated with HDP and 74 (14.8%) MC with HDP, and the difference between the two groups was statistically significant (p=.011). After stratification by chorionicity, in the DC twin, there were significantly more deliveries in the GH group, MPE group, and SPE group before 37 weeks than in the no-HDP group (p=.000). Statistically significant differences were found among the four groups in the average small fetus birthweight, the intertwin weight difference, the relative weight discordance, the growth discordance, the incidence of very low birth weight (VLBW), low birth weight (LBW), and the Apgar scores of the small fetus (p<.05). In MC twins, By comparison only on the average gestational age at delivery, the average small fetus birthweight, Apgar scores of large and small fetuses among the four groups, the difference was statistically significant (p<.05). According to multiple linear regression analysis, after controlling for multiple confounding factors, it was found when the degree of HDP in DC twins increased by one grade, the small fetus birthweight decreased by an average of 19.044 g (p=.007), the intertwin weight difference increased by an average of 14.311 g (p=.034), the relative weight discordance increased by an average of 0.6% (p=.013), and the gestational age at delivery decreased by an average of 0.160 weeks (p=.001).

CONCLUSIONS

The perinatal outcomes of different chorionic twins with HDP are different. HDP has a greater impact on the perinatal outcomes of DC twins. The risk of adverse perinatal outcomes in DC twin pregnancy will increase accordingly with each increase in the grade of HDP, but HDP has little or no relevance on the perinatal outcomes of MC twins.

A Review of Research Progress of Pregnancy with Twins with Preeclampsia

Preeclampsia has a significant long-term effect on the health of both mothers and babies. Preeclampsia-related pregnancy complications increase the morbidity and mortality of pregnant women and their fetuses by 5-8%. The recent advancement of assisted reproductive technology, combined with a rise in the number of elderly pregnant women, has resulted in pregnancy incidence with twins. Twins pregnant women have a 2-3 times greater risk of developing preeclampsia than singleton pregnant women, and it happens sooner and progresses faster. It is more severe and may appear in an atypical way. End-organ damage, such as renal failure, stroke, cardiac arrest, pulmonary edema, placental abruption, and cesarean section, are related maternal complications. Fetal growth retardation, stillbirth, and premature delivery with obstetric signs are all fetal complications. According to studies, all multiple pregnancies can take low-dose aspirin (60-150 mg) to minimize the risk of preeclampsia. To improve pregnancy outcomes and reduce the inherent risk of pregnancy with twins, twins should be handled as a high-risk pregnancy and treated differently than singletons. The literature on twin pregnancy with preeclampsia is the subject of this review. It will examine the current state of research on preeclampsia in pregnancy with twins, including the occurrence, diagnosis, and pathophysiological process. Moreover, the effect of pregnancy with twins on the perinatal outcome and pregnancy management of pregnancy with twins, including blood pressure management and preeclampsia prevention and treatment, is examined in this literature review. The goal is to figure out what kind of diagnosis and care you may need.

Clinical risk factors for preeclampsia in twin pregnancies

Background

Preeclampsia is a common obstetric complication. The rate of preeclampsia is increased in twin pregnancies. The aim of this study was to assess the clinical risk factors for developing preeclampsia in twin pregnancies.

Methods

A case-control study was carried out among women with twin pregnancies who delivered at gestational age more than 23 weeks at King Chulalongkorn Memorial Hospital, Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand, from 2003 to 2019. The data were retrieved from electronic medical records. Multivariate logistic regression analysis was used to find the risk factors.

Results

A total of 1,568 twin pregnancies were delivered during the study period and 182 cases (11.6%) developed preeclampsia. 172 cases with preeclampsia and 516 controls were selected for analysis. After certain variables were adjusted in the multivariate logistic regression analysis, the clinical factors associated with preeclampsia in twin pregnancies were nulliparity (adjusted odds ratio (OR) 1.57, 95% confidence interval (CI) 1.02–2.41) and chronic hypertension (adjusted OR 6.22, 95%CI 1.98–19.57). Low gestational weight gain was a significant protective factor against the development of preeclampsia (adjusted OR 0.50; 95%CI 0.32–0.77).

Conclusion

The clinical risk factors for developing preeclampsia in twin pregnancies were nulliparity and chronic hypertension. These risk factors are of value to identify twin pregnant women at risk for preeclampsia and in implementing primary prevention.

Multiple Gestations and Hypertensive Disorders of Pregnancy: What Do We Know?

PURPOSE OF REVIEW

The occurrence of hypertensive disorders of pregnancy (HDP) including gestational hypertension, chronic hypertension, preeclampsia, and eclampsia is proportional to the number of fetuses: singletons 6.5%, twins 12.7%, and triplets 20.0%. Literature on HDP in multifetal gestation is sparse compared with singletons. We aim to summarize the current evidence on HDP, specifically in twins.

RECENT FINDINGS

HDP occurs more frequently, at an earlier gestational age, and can present more severely and atypically in twin pregnancies. HDP in twins carries a higher risk of maternal/fetal morbidity and mortality including renal failure, stroke, cardiac arrest, pulmonary edema, placental abruption, cesarean delivery, fetal growth restriction, and iatrogenic preterm delivery. Low-dose aspirin (60-150 mg) should be initiated in all multifetal pregnancies to reduce the risk of preeclampsia. To improve outcomes and reduce inherent risks associated with multiple gestations, twins should be managed as high-risk pregnancies, and different from singletons.

Impact of growth discordance in twins on preeclampsia based on chorionicity

BACKGROUND

Despite extensive investigations over the last decade, preeclampsia remains an unpredictable pregnancy complication causing perinatal morbidity and mortality worldwide, particularly in twin pregnancies.

OBJECTIVE

This study aimed to determine the relationship between growth discordance in twin pregnancies and the risk for preeclampsia based on chorionicity.

STUDY DESIGN

This was a retrospective single-center study that included 2122 women with twin pregnancies who were admitted to a tertiary hospital between January 2013 and June 2016. Growth discordance was defined as twin birthweight difference ≥20%. Logistic regression models were used to analyze the association between growth discordance and risk for gestational hypertension-preeclampsia in all subjects. Stratified sampling by twin chorionicity (dichorionic and monochorionic) was also conducted. Further analysis was performed to estimate the association between the degree of growth discordance and gestational hypertension-preeclampsia risk in monochorionic and dichorionic twin pregnancies.

RESULTS

The prevalence of growth discordance was 17.6%. In all subjects, growth discordance was associated with increased risk for gestational hypertension-preeclampsia. After stratification by twin chorionicity, growth discordance was associated with an increased risk for gestational hypertension preeclampsia (adjusted odds ratio [AOR], 1.84; 95% confidence interval [CI], 1.26-2.67) and preeclampsia (AOR, 1.82; 95% CI, 1.21-2.73), including mild preeclampsia (AOR, 1.86; 95% CI, 1.02-3.37), severe preeclampsia (AOR, 1.78; 95% CI, 1.06-2.97; P<.05), and early-onset preeclampsia (AOR, 2.98; 95% CI, 1.40-6.32), in the dichorionic twin pregnancy group; however, no significant association was found in the monochorionic twin pregnancy group. A 10% increment of growth discordance in the dichorionic twin pregnancy group was associated with an elevated risk for gestational hypertension preeclampsia (AOR, 1.20; 95% CI, 1.02-1.41) and preeclampsia (AOR, 1.24; 95% CI, 1.04-1.48), including severe preeclampsia (AOR, 1.28; 95% CI, 1.04-1.59) and early-onset preeclampsia (AOR, 1.47; 95% CI, 1.08-2.00), but no significant association was found in the monochorionic twin pregnancy group.

CONCLUSION

Growth discordance is associated with an increased risk for preeclampsia in dichorionic but not in monochorionic twin pregnancy. In addition, the prevalence of preeclampsia increases significantly with increasing degree of growth discordance, reflecting a dose-response relationship in dichorionic twin pregnancy.

Number of embryos transferred and diagnosis of preeclampsia

BACKGROUND

Multiple births and first pregnancy are associated with higher preeclampsia risk. It is unknown if the transfer of multiple embryos or first embryo transfer with assisted reproductive technology (ART) is also associated with greater preeclampsia risk.

METHODS

We performed a retrospective cohort study of IVF clinics and hospitals in Massachusetts. We used linked ART surveillance, birth certificate, and maternal hospitalization discharge data for 21,188 births, considering resident singleton (12,810) and twin (8378) live-births from autologous or donor eggs from 2005 to 2012. We used log binomial and Poisson regression to calculate adjusted relative risks (aRRs) and 95% confidence intervals (CI) for the association between preeclampsia and predictors of preeclampsia. Outcomes were stratified by singleton and twin birth, donor versus autologous cycles, and use of fresh versus cryopreserved embryos.

RESULTS

Considering all singleton births, the transfer of multiple embryos increased the risk of preeclampsia [aRR = 1.10 (95% CI: 1.01-1.19)]. Relative risks were greatest for fresh non-donor cycles [aRR = 1.14 (95% CI: 1.03-1.26)]. Vanishing twin and number of prior ART cycles was not associated with preeclampsia among singleton births [aRR = 1.18 (95% CI: 0.91-1.53)], and aRR = 1.01 (95% CI: 0.96-1.05)], respectively. Considering all twin births, the transfer of > 2 embryos increased the risk of preeclampsia [aRR = 1.09 (95% CI: 1.001-1.19)]. Vanishing triplet and number of prior ART cycles were not associated with preeclampsia among twin births [aRR = 0.93 (95% CI: 0.69-1264), and aRR = 0.98 (CI: 0.95-1.02)], respectively.

CONCLUSIONS

Among ART births, the transfer of more than 1 embryo for singleton gestations and more than 2 embryos for twin gestations increased the risk for preeclampsia diagnosis.

Maternal Serum Placental Growth Factor, Soluble Fms-Like Tyrosine Kinase-1, and Soluble Endoglin in Twin Gestations and the Risk of Preeclampsia-A Systematic Review

Multiple gestation is one of the key risk factors for the occurrence of preeclampsia (PE). Soluble fms-like tyrosine kinase-1, placental growth factor, and soluble endoglin are molecules involved in the process of angiogenesis with a proven role in the pathogenesis of PE. The aim of the review was to summarize available data on maternal serum levels of the above-mentioned factors and their usefulness in predicting PE in twin pregnancies. Only original research articles written in English were considered eligible. Reviews, chapters, case studies, conference papers, experts’ opinions, editorials, and letters were excluded from the analysis. No publication date limitations were imposed. The systematic literature search using PubMed/MEDLINE, Scopus, Embase, and Cochrane Library databases identified 338 articles, 10 of which were included in the final qualitative analyses. The included studies showed significant differences in maternal serum levels of the discussed factors between women with twin pregnancies with PE and those who did not develop PE, and their promising performance in predicting PE, alone or in combination with other factors. The identification of the most effective algorithms, their prompt introduction to the clinical practice, and further assessment of the real-life performance should become a priority.

Prevalence and risk of pre-eclampsia and gestational hypertension in twin pregnancies: a population-based register study

OBJECTIVES

The aim of this study was to assess the prevalence and risk of pre-eclampsia and gestational hypertension in twin pregnancies compared with singleton pregnancies.

DESIGN

Population-based cohort study.

SETTING

Medical Birth Registry of Norway and Statistics Norway.

PARTICIPANTS

929 963 deliveries with 16 174 twin pregnancies in 1999-2014.

METHODS

Pre-eclampsia prevalences in twin and singleton pregnancies were described in percentages. Multivariable regression analyses were performed to assess the risks of pre-eclampsia and gestational hypertension in twin pregnancies compared with those in singleton pregnancies, adjusted for previously known risk factors.

PRIMARY AND SECONDARY OUTCOME MEASURES

Prevalence and risk of pre-eclampsia and gestational hypertension.

RESULTS

The prevalence of pre-eclampsia in the study population was 3.7% (3.4% in singleton pregnancies, 11.8% in twin pregnancies (p=0.001)). The OR for pre-eclampsia in twin pregnancies was three to fourfold compared with singleton pregnancies (OR 3.78; 95% CI 3.59 to 3.96). After adjustment for known risk factors, twin pregnancy remained an independent risk factor for pre-eclampsia (adjusted OR 4.07; 95% CI 3.65 to 4.54). The prevalence of gestational hypertension was 1.7% in women with singleton pregnancies and 2.2% in those with twin pregnancies (OR 1.27; 95% CI 1.14 to 1.41). After adjustment for known risk factors, gestational hypertension was not significantly associated with twin pregnancy.

CONCLUSIONS

The risk of pre-eclampsia in twin pregnancies was three to fourfold compared with singleton pregnancies, regardless of maternal age, parity, educational level, smoking, maternal comorbidity or in vitro fertilisation. The risk of gestational hypertension was not increased in women with twin pregnancies after adjustment for the main risk factors.

Validation of competing-risks model in screening for pre-eclampsia in twin pregnancy by maternal factors

OBJECTIVE

To examine the predictive performance of the competing-risks model in screening for pre-eclampsia (PE) by maternal demographic characteristics and medical history in twin pregnancy, in a training dataset used for development of the model and a validation dataset.

METHODS

The data for this study were derived from two prospective non-intervention multicenter screening studies for PE in twin pregnancies at 11 + 0 to 13 + 6 weeks' gestation. The first study of 2219 women, which was reported previously, was used to develop the competing-risks model for prediction of PE and is therefore considered to be the training set. The validation study comprised 2999 women. Patient-specific risks of delivery with PE at < 34 (early), < 37 (preterm) and < 41 + 3 (all) weeks' gestation were calculated using the competing-risks model and the performance of screening for PE in the training and validation datasets was assessed. We examined the predictive performance of the model by, first, its ability to discriminate between the PE and no-PE groups using the area under the receiver-operating characteristics curve (AUC) and, second, calibration, which assesses agreement between the predicted risk and observed incidence of PE.

RESULTS

The incidence of early PE, preterm PE and all PE in the training and validation datasets was similar (1.8% vs 1.4%, 5.6% vs 5.6% and 7.7% vs 7.2%, respectively) and this was substantially higher than in our previous studies in singleton pregnancies. The training and validation datasets had similar AUCs for early PE (0.670 (95% CI, 0.593-0.747) vs 0.677 (95% CI, 0.594-0.760)), preterm PE (0.666 (95% CI, (0.617-0.715) vs 0.652 (95% CI, 0.609-0.694)) and all PE (0.656 (95% CI, 0.615-0.697) vs 0.644 (95% CI, 0.606-0.682)). Calibration plots of the predictive performance of the competing-risks model demonstrated that, in both the training and validation datasets, the observed incidence of PE was lower than the predicted one and such overestimation of risk was particularly marked for early PE.

CONCLUSIONS

Discrimination and calibration of the competing-risks model for PE in a validation dataset are consistent with those in the training dataset. However, the model needs to be adjusted to correct the observed overestimation of risk for early PE. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Placental Histopathology Differences and Neonatal Outcome in Dichorionic-Diamniotic as Compared to Monochorionic-Diamniotic Twin Pregnancies

OBJECTIVE

We aimed to compare the differences in placental histopathology lesions and pregnancy outcome in dichorionic-diamniotic (DCDA) versus uncomplicated monochorionic-diamniotic (MCDA) twin gestations.

STUDY DESIGN

Maternal characteristics, neonatal outcome, and placental histopathology reports of all twin deliveries between 24 and 41 weeks were reviewed. Excluded were pregnancies complicated by twin-to-twin transfusion syndrome, twin anemia-polycythemia sequence, selective intrauterine growth restriction, placenta previa, intrauterine fetal death, and malformation. Placental lesions were classified to maternal/fetal vascular malperfusion lesions. Umbilical cord abnormalities included hypo-/hypercoiling and abnormal insertion. Composite adverse neonatal outcome was defined as 1 or more early complications. Small for gestational age (SGA) was defined as birth weight ≤10th percentile.

RESULTS

The DCDA group (n = 362) was characterized by higher rates of assisted reproductive techniques ( P < .001) and nulliparity ( P = .03) as compared to the MCDA group (n = 65). Gestational age at delivery was similar between groups. Placental maternal vascular malperfusion lesions were more common in placentas from DCDA group (38.2% vs 23.1%; P = .016), while fetal vascular malperfusion lesions and abnormal cord insertion were more common in placentas from MCDA group ( P = .027; P< .001). The SGA and composite adverse neonatal outcome were more common in the MCDA group ( P = .031 and P = .038, respectively). By multivariate regression analysis, composite adverse neonatal outcome was found to be independently associated with the MCDA group, adjusted odds ratio (aOR) = 1.2, 95% confidence interval (CI) = 1.04 to 1.89, P = .041, and with placental fetal malperfusion lesions aOR = 1.3, 95% CI = 1.1 to 2.09, P = .038.

CONCLUSION

Placental pathology differs between MCDA and DCDA twin pregnancies. Adverse neonatal outcome in uncomplicated MCDA twins, as compared to DCDA twins, could be related to increased placental fetal malperfusion lesions and abnormal cord insertion.

Competing-risks model in screening for pre-eclampsia in twin pregnancy by maternal characteristics and medical history

OBJECTIVE

A survival-time regression model for gestational age at delivery with pre-eclampsia (PE) in singleton pregnancy, using maternal demographic characteristics and medical history, was reported previously. The objective of this study was to extend this model to dichorionic (DC) and monochorionic (MC) twin pregnancy.

METHODS

The study population included 1789 DC and 430 MC twin pregnancies and 93 297 singleton pregnancies. A survival-time model for gestational age at delivery with PE was developed from variables of maternal characteristics and medical history. The risk of PE with delivery < 37 weeks and < 42 weeks in twin pregnancies was determined and compared with that in singleton pregnancies.

RESULTS

In singleton pregnancies comprising women of Caucasian racial origin, mean weight of 69 kg at 12 weeks' gestation, mean height of 164 cm, nulliparous, with spontaneous conception, no family history of PE and no history of diabetes mellitus, systemic lupus erythematosus or antiphospholipid syndrome, the mean of the Gaussian distribution of gestational age at delivery with PE was 55 weeks. In DC twins with PE, mean gestational age at delivery was shifted to the left by 8.2 (95% CI, 7.2-9.1) weeks and in MC twins it was shifted to the left by 10.0 (95% CI, 8.5-11.4) weeks. The risk of delivery with PE occurring at, or before, a specified gestational age is given by the area under the fitted distribution curve. For a reference population with the above characteristics, the estimated risk of PE < 37 weeks' gestation, assuming no other cause of delivery, was 0.6% for singletons, 9.0% for DC twins and 14.2% for MC twins; the respective values for PE < 42 weeks were 3.6%, 27.0% and 36.5%.

CONCLUSIONS

A model based on maternal characteristics and medical history has been developed for estimation of patient-specific risks for PE in DC and MC twin pregnancy. Such estimation of the a-priori risk for PE is an essential first step in the use of Bayes' theorem to combine maternal factors with biomarkers for the continuing development of more effective methods of screening for the disease. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Hidden high rate of pre-eclampsia in twin compared with singleton pregnancy

OBJECTIVES

To examine the gestational age at delivery in dichorionic (DC) and monochorionic (MC) twin pregnancies, with and without pre-eclampsia (PE), and to determine the relative risk of total and preterm PE compared with that in singleton pregnancies.

METHODS

This was a screening study for PE in twin pregnancies undergoing first-trimester combined screening for aneuploidy and subsequently delivering two phenotypically normal live or stillborn babies at ≥ 24 weeks' gestation. The distribution of gestational age at delivery in DC and MC twins was determined and compared with that in singleton pregnancies from the same population. The relative risk for total and preterm PE in twins compared with singleton pregnancies was determined. Kaplan-Meier estimates of the cumulative incidence of PE in twin and singleton pregnancies, assuming no other cause for delivery, were determined and hazard ratios for twins relative to singletons were obtained from a Cox proportional hazards regression model.

RESULTS

The incidence of PE in singletons was 2.3% (2162/93 297), in DC twin pregnancies was 8.1% (145/1789) and in MC twin pregnancies was 6.0% (26/430). Compared with singletons, the relative risk of total PE was 3.5 for DC twins and 2.6 for MC twins. Delivery < 37 weeks' gestation occurred in 5.5% of singletons, 46.5% of DC twins and 91.4% of MC twins. The incidence of preterm PE was 0.6%, 5.5% and 5.8% for singletons, DC twins and MC twins, respectively. Compared with singletons, the relative risk of preterm PE was 8.7 for DC twins and 9.1 for MC twins. In the Cox proportional hazards regression model, the hazard ratios for DC and MC twin pregnancies relative to singleton pregnancies were 14 and 23, respectively.

CONCLUSIONS

The relative risk of preterm PE in DC and MC twins is similar and substantially higher than in singleton pregnancies. In ongoing twin pregnancies, the high relative risk of PE may merit a higher intensity of monitoring than is routine for singleton pregnancies. © 2017 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Clinical characteristics of fetal and neonatal outcomes in twin pregnancy with preeclampsia in a retrospective case-control study: A STROBE-compliant article

The aim of our study was to compare the clinical characteristics of fetal and neonatal outcomes in twin pregnancies between women with preeclampsia (PE) and those with normotension in a Chinese population.There were 143 preeclamptic women and 367 normotensive women with twin pregnancies included in this retrospective case-control study. The baseline characteristics and perinatal outcomes were collected and compared between the groups. Multiple logistic regression and linear regression were used to assess the correlations between PE and the outcomes.Significant increases were observed in the frequencies of preterm delivery (OR = 2.75, P < 0.001), iatrogenic preterm birth (OR = 3.52, P < 0.001), and IUGR (OR = 2.94, P = 0.001) in the PE group, and the PE group had more than a 2-fold risk of adverse neonatal outcomes. Preeclamptic twin neonates had lower birth weights (β = -147.34, P = 0.005; β = -169.47, P = 0.001). The comparison on the discordance of intertwin weight was not significantly different.Twin pregnancies with PE are associated with worse perinatal outcomes. The adverse outcomes of preeclamptic twin pregnancies may be associated with lower birth weights rather than the discordance of the intertwin weight, which requires further confirmation. The results may provide helpful references for better clinical assessments, evaluations of prognosis, and a deeper understanding of preeclamptic twin pregnancies.

Hypertensive disorders during monozygotic and dizygotic twin gestations: A population-based study

OBJECTIVE

To determine whether the incidence of hypertensive disorders is different in monozygotic compared to dizygotic twin pregnancies.

METHODS

A registry-based survey of twin pregnancies delivered during 2003 to 2012. We used the best clinical estimate of zygosity based on the concept that all monochorionic twins are monozygotic and all unlike-sex pairs are dizygotic, thus excluding same-sex dichorionic twin gestations for which zygosity cannot be ascertained on clinical grounds. Study cohorts were twin pregnancies with or without preeclampsia and gestational hypertension.

RESULTS

A total of 3419 twin gestations met the inclusion criteria, of which 442 (12.9%) were monochorionic and 1255 (36.7%) were unlike-sex twins, excluding 1722 same-sex dichorionic twin gestations (50.4%). There was no significant difference in the incidence of preeclampsia (OR: 0.9; 95% CI: 0.4-2.0 for monozygotic males and OR: 0.6; 95% CI: 0.3-1.4 for monozygotic females) and gestational hypertension (OR: 0.7; 95% CI: 0.2-2.5 for monozygotic males, and OR: 0.7; 95% CI: 0.2-2.3 for monozygotic females) between monochorionic and unlike-sex pairs. Maternal prepregnancy obesity and nulliparity were the only significant associated factors of preeclampsia (OR: 3.8; 95% CI: 2.0-7.0, and OR: 2.5; 95% CI: 1.4-4.4, respectively). Maternal prepregnancy obesity (OR: 5.5; 95% CI: 2.5-12.2), maternal age ≥36 years (OR: 2.5; 95% CI: 1.1-6.1), and family history of hypertension (OR: 2.6; 95% CI: 1.3-5.1) were significantly associated with gestational hypertension.

CONCLUSION

Based on a large population-based dataset and on the best clinical estimate of twin zygosity, it appears that zygosity is not associated with hypertensive disorders in twin gestations.

Do preeclampsia symptoms resolve after intrauterine death of a fetus?

We present two cases of twin pregnancies without resolution of preeclamptic symptoms after intrauterine death of one twin.

Case 1:

A nulliparous woman aged 37 years was referred at 26 weeks of gestation because of arterial hypertension, edema, and growth restriction in one twin. Three weeks later the restricted twin died. During the following three weeks, ultrasound examinations showed a reduced growth velocity of the surviving fetus and reversed umbilical flow. At the end of the 34^th week of gestation, cesarean section was performed and a healthy female infant was delivered.

Case 2:

A nulliparous woman aged 33 years with a 27-week twin pregnancy was referred because of arterial hypertension and discordant growth. The restricted twin died at 31 weeks of gestation. Following the death, within two weeks the growth of the co-twin started to slow down and reversed end diastolic flow presented. At the end of the 33^rd week of gestation, cesarean section was performed and a healthy female infant was delivered.

The interesting point of these cases was the secondary effects on the co-twins. During the time after intrauterine deaths of one twin, the surviving fetuses started to show a reduced growth velocity and reversed umbilical flow and mothers had increased blood pressure and proteinuria again. We think that both cases are evidence of late on-set systemic maternal effects (such as systemic maternal endothelial activation and/or systemic maternal inflammatory response) depends on preeclampsia.

Twin Chorionicity and the Risk of Hypertensive Disorders: Gestational Hypertension and Pre-eclampsia

Twin gestation is known to be a risk factor for hypertensive disorders of pregnancy. However, the relationship between hypertensive disorders (pre-eclampsia (PE) and gestational hypertension (GH)) and chorionicity of twin pregnancy is unclear, and published data is conflicting. We decided to analyze the relationship between placentation and prevalence of hypertensive disorders. It was a retrospective cohort study. 312 twin pregnancies delivered between 2009 and 2014 were analyzed, 79 of which were monochorionic and 233 dichorionic. The occurrence of PE and GH was established according to American College of Obstetricians and Gynecologists' (ACOG) guidelines. Hypertensive disorders were diagnosed significantly more often in dichorionic than in monochorionic twin pregnancies (19.7% vs. 8.9%; OR = 2.53 95% CI 1.04-6.45; p = .03). PE occurred more frequently in DCP (13.3% vs. 3.8%; OR = 3.88 95% CI 1.09-16.46; p = .02). There were no differences between those two groups in the prevalence of GH (6.4% vs. 5.1%; p = .79). The logistic regression model for the occurrence of PE included chorionicity, mother's age lower than 18 or higher than 40, pre-gestational obesity, in vitro fertilization, primiparity, gestational age at delivery, gestational diabetes, and active smoking. It showed that dichorionicity remained an independent risk factor for PE (adjusted OR = 4.97.0 95% CI 1.06-23.38; p = .04). Dichorionicity seems to be a risk factor for PE but not for GH development.

Perinatal and obstetric outcomes of dichorionic vs trichorionic triplet pregnancies

BACKGROUND

Clinical management and outcome of multiple gestation can be affected by chorionicity. In triplet pregnancies, fetal death has been associated with dichorionic (DC) and monochorionic placentation. Studies evaluating triplet pregnancy outcomes in relation to chorionicity have been few and may not reflect contemporary antenatal and neonatal care.

OBJECTIVE

The objective of this study was to compare obstetric and perinatal outcomes in DC and trichorionic (TC) triplet pregnancies.

STUDY DESIGN

We performed a retrospective cohort study of triplet pregnancies that delivered at ≥20 weeks' gestation at 2 Chicago area hospitals from January 1999 through December 2010. Chorionicity was determined by pathology specimen. Maternal and infant charts were reviewed for obstetric and perinatal outcomes.

RESULTS

The study population included 159 pregnancies (477 neonates) of which 108 were TC (67.9%) and 51 were DC (32.1%). Over 94% of mothers in this study had all 3 infants survive to discharge regardless of chorionicity. No difference was found in perinatal mortality rate between DC and TC triplets (3.3% vs 4.6%; P = .3). DC triplets were significantly more likely to be very low birthweight (41.8% vs 22.2%; odds ratio, 2.2; 95% confidence interval, 1.2-4.2; P = .02) and to deliver at <30 weeks (25.5% vs 8.3%; odds ratio, 6.1; 95% confidence interval, 1.9-19.4; P = .002) compared to TC triplets. Criteria for twin-twin transfusion syndrome (TTTS) were present in 3 DC triplet pregnancies (5.9%). Neonates in pregnancies complicated by TTTS were less likely to survive 28 days as compared to neonates from DC pregnancies that were not affected by TTTS (P = .02) or TC neonates (P = .02) Neonatal survival was similar in DC pregnancies not affected by TTTS and TC pregnancies (98.6% and 96.6%; P = .7).

CONCLUSION

Although perinatal mortality did not correlate with chorionicity, DC pregnancies were more likely to deliver <30 weeks' gestational age and have very low birthweight neonates. Neonatal mortality appears to be mediated by the presence or absence of TTTS as 28-day survival was worse in DC pregnancies complicated by TTTS, but similar between DC pregnancies not affected by TTTS and TC pregnancies.

The impact of chorionicity on maternal pregnancy outcomes

OBJECTIVE

Women carrying twin pregnancies often receive similar counseling, regardless of chorionicity, with the notable exception of twin-twin transfusion syndrome (TTTS); however, little is known about whether the presence of 1 vs 2 placentas confers dissimilar maternal risks. We sought to determine differences in maternal and neonatal outcomes based on chorionicity.

STUDY DESIGN

This was a retrospective cohort study of all twin pregnancies at our institution undergoing routine second-trimester ultrasound for anatomic survey from 1990 through 2010. Secondary outcomes included other adverse maternal and neonatal outcomes. Relative risks and adjusted odds ratios (aORs) were calculated. Cluster analysis was used to account for nonindependence of twin pairs.

RESULTS

Of 2301 pregnancies, 1747 (75.9%) were dichorionic and 554 (24.1%) were monochorionic. Rates of preeclampsia, gestational diabetes, placental abruption, placenta previa, preterm labor, and preterm premature rupture of membranes (PPROM) were not significantly different in dichorionic vs monochorionic pregnancies. Early preterm delivery less than 34 weeks (aOR, 1.47; 95% confidence interval [CI], 1.17-1.86) and less than 28 weeks (aOR, 2.58; 95% CI, 1.58-4.20) were more likely in monochorionic twins, as was neonatal intensive care unit admission (aOR, 1.41; 95% CI, 1.12-1.78). Monochorionic twins delivered earlier at a mean gestational age of 34.2 weeks vs 35.0 weeks for dichorionic twins (P < .001). Hospital length of stay was significantly longer for monochorionic twins with a mean of 13.7 days vs 10.8 days for dichorionic twins (P = .01).

CONCLUSION

There are no significant differences in maternal outcomes by chorionicity; however, monochorionicity is associated with increased fetal risks. This information may be helpful in guiding more targeted counseling to expectant parents of twins that, although the presence of an additional placenta does not confer additional maternal risks, monochorionic infants tend to deliver earlier and require longer hospital stays.

Pre-eclampsia (PE) and Chorionicity in Women with Twin Gestations

BACKGROUND

Pre-Eclampsia (PE) affects 6-31% of pregnant women with multiple gestations. There are conflicting reports on the association of PE with Chorionicity and zygosity; however, there is a lack of information on this potential association in a population of pregnant Asian Indian women.

AIM

To determine as to whether chorionicity and zygosity were associated with PE in a population of Asian Indian women with twin gestations.

SETTINGS AND DESIGN

A retrospective observational study was done at a single tertiary care centre in Southern India.

MATERIAL AND METHODS

The study included pregnant women with twin gestations, who was delivered at the study institute in 2012. Hypertension in pregnancy was categorized, based on the criteria of the International Society for the Study of Hypertension in Pregnancy. Chorionicity was determined by using ultrasonography and zygosity was determined, based on clinical criteria. Point estimates and the 95% Confidence Intervals (CI) around point estimates of PE and associations of chorionicity and zygosity with PE were determined by using bivariate analysis, logistic regression models and area under Receiver Operator Characteristic (ROC) curves.

RESULTS

This study included 208 women with twin gestations. The incidence of PE in dichorionic twin gestations was 13.17% (n=22, 95% CI: 8.66, 18.96), it was 4.87% (n=2, 95% CI: 0.83, 15.19) in monochorionic twin gestations, it was 16.36% (n=9, 95% CI: 8.29, 27.91) in dizygous twin gestations and it was 4.88% (n=2, 95% CI: 0.83, 15.19) in monozygous twin gestations. Neither chorionicity (adjusted OR: 2.59, 95% CI: 0.55, 12.19) nor zygosity (adjusted OR 2.72, 95% CI: 0.49, 15.13) were associated with PE In a multivariate logistic regression model.

CONCLUSION

Although it was not statistically significant, the clinical incidence of PE was higher in dichorionic and dizygous twin gestations.