Does risk of preeclampsia differ by twin chorionicity?

Abstract

Objective: Examine whether dichorionic (DC) and monochorionic (MC) twins exhibit different rates and severity of preeclampsia.

Methods: Retrospective cohort study of 695 twin pregnancies from 2002 to 2007. DC pregnancies were compared to MC pregnancies, with the primary outcome of interest being development of preeclampsia, and the secondary outcome being severity of preeclampsia. Chi square test compared proportions and multivariable analyses controlled for potential confounders.

Results: Any preeclampsia developed in 21.1% (104/492) of DC and 10.8% (22/203) of MC pregnancies (p?=?0.001), mild preeclampsia in 13.8% (68/492) of DC and 4.9% (10/203) of MC pregnancies (p?=?0.001) and severe preeclampsia in 7.3% (36/492) of DC and 5.9% (12/203) of MC pregnancies (p?=?0.506). DC pregnancies showed higher odds of mild preeclampsia compared to MC pregnancies (aOR 5.85, 95% CI 1.31–26.13) after controlling for several potential confounders including gestational age at delivery.

Conclusions: A statistically significant larger proportion of women with DC twins developed any preeclampsia, and specifically mild preeclampsia, compared to those with MC twins. Additionally, after controlling for several potential confounders, women with DC pregnancies demonstrated higher odds of developing mild preeclampsia compared to those with MC pregnancies. Mechanisms of preeclampsia development may differ by twin chorionicity.     

The impact of chorionicity on umbilical cord acid–base values in twin gestations

Objective: To evaluate the impact of chorionicity on inter-twin differences in acid–base status at birth.

Methods: Records for twin pregnancies delivered at ??24 weeks' gestation from 1 January 1990 to 31 June 2000 were reviewed. Collected data included maternal demographics, gestational age, fetal presentation, anesthesia, delivery mode, inter-twin interval, umbilical artery (UA) and venous (UV) acid–base values, Apgar scores and birth weights. The influence of chorionicity on umbilical cord biochemistry was evaluated. (p?<?0.05 was considered significant.)

Results: Analysis was carried out in 87 twin pairs (29 monochorionic, MC; and 58 dichorionic, DC). MC and DC twins were similar in maternal age (25.5 vs. 28.2 years), estimated gestational age (33.7 vs. 33.6 weeks), Cesarean delivery (55.2 vs. 52.6%), delivery interval (10 v s.5?min) and respective birth weights (twin A,1882 vs. 1981; and twin B,1828 vs. 1872?g). MC first twins had a higher UA pH (7.31?±?0.05 vs. 7.26?±?0.08; p?=?0.0005) than DC first twins. MC first and second twins had higher UA and UV bicarbonate levels than their DC counterparts (ΔpH?=?21.7?±?5.1 vs. 18.5?±?3.1?mmol/l and 22.0?±?3.5 vs. 19.6?±?2.5?mmol/l, respectively; p?=?0.003). MC twins were more discordant in UA pH than DC twins (ΔpH?=?0.043?±?0.09 vs. 0.003?±?0.07; p?=?0.009). MC and DC twins had a similar venous pH (ΔpH?=?0.01?±?0.06 vs. 0.02?±?0.06; p?=?0.5).

Conclusions: There is a significant association between placental chorionicity and umbilical cord biochemistry in twins. Although it is possible that the mechanism of this finding is related to placental angioarchitecture, it is unlikely to be a result of simple mixing of blood volumes between twins. The physiology of underlying processes requires further study.     

Intertwin crown-rump length discordance in the prediction of fetal anomalies,fetal loss and adverse perinatal outcome

Objective: To assess the risks of fetal anomalies, fetal loss and adverse perinatal outcome in a cohort of first-trimester intertwin crown-rump length (CRL) discordant twins, stratified by chorionicity and the degree of CRL discordance.

Method: Four-hundred-and-seventy-one twin pregnancies were scanned during an 8-year period at 11–14 weeks, and those with an intertwin CRL discordance ≥10% were compared with concordant twins. Outcomes were also compared between monochorionic and dichorionic twins and between moderate (10–16%) and severe (>16%) discordance.

Results: Four-hundred-and-five twin pregnancies, 65 discordant and 340 concordant, were follow-up. Discordant twin pregnancies were at significant higher risk of chromosomal (OR?=?11.42; 95%?CI: 2.78–46.94) and structural anomalies (OR?=?5.91; 95%?CI: 2.25–15.54), spontaneous fetal loss (OR?=?4.23; 95%?CI: 1.79–10.01), birthweight discordance (OR?=?2.8; 95%?CI: 1.48–5.65) and small-for-gestational age (OR?=?3.48; 95% CI: 1.78–6.79). Similar differences (except for birthweight discordance) were observed among dichorionic twins. Among monochorionic, increased frequencies were only seen for structural anomalies, birthweight discordance and small newborns. Severe CRL discordance presented with higher rates of structural anomalies, stillbirth, birthweight discordance and small newborns.

Conclusion: Intertwin CRL discordance (≥10%) results in an increased risk of fetal anomalies and growth restriction that increases in severe CRL discordance (≥16%).     

Twin chorionicity and the risk of adverse perinatal outcome.

OBJECTIVE: To evaluate the impact of chorionicity on the perinatal outcomes of twin pregnancies complicated by twin-twin transfusion syndrome (TTS) or selective intrauterine growth restriction (sIUGR). METHOD: Pregnancies with 127 monochorionic (MC) and 109 dichorionic (DC) twins were followed up, and TTS and sIUGR incidence as well as morbidity and mortality were evaluated. RESULTS: The incidence of intrauterine fetal death was higher in MC than in DC pregnancies (6.5% vs. 1%), and higher in MC pregnancies complicated by TTS (5 deaths in 10 pregnancies [50%]) or sIUGR (2 in 9 [22%]). The incidence of sIUGR was similar in MC and DC pregnancies (7% vs. 5%), and the incidence of TTS was 8% in MC pregnancies (95% confidence interval, 3.2-12.8). Neonatal neurological and respiratory morbidity was higher among MC twins, and the increase in neonatal complications was linked to TTS and sIUGR. Uncomplicated MC and DC pregnancies had similar perinatal outcomes. CONCLUSION: The incidence of neonatal complications was higher in MC twins born of pregnancies complicated by TTS or sIUGR. Although the incidence of sIUGR was similar in MC and DC pregnancies, there was a trend towards worse outcomes in MC pregnancies affected by sIUGR.     

Monoamniotic twins in contemporary practice: a single-center study of perinatal outcomes

Objective.?The previous studies of monochorionic monoamniotic (MCMA) twins reported perinatal mortality rates as high as 70–80%. The recent trends have been towards significantly improved outcomes, though results from all studies have not been consistent.

Method.?A retrospective cohort analysis of all MCMA pregnancies ≥20 weeks delivered in a single university institution from 2001 to 2009, using a computerised hospital database. MCMA twins are managed by a close antenatal surveillance program, preferably elective admission at 26–28 weeks, daily non-stress tests, regular assessment of fetal growth with the goal of cesarean delivery by 34 weeks.

Results.?Of the 25 MCMA pregnancies delivered, 98% (49/50) of twins were live-born. All women were delivered by cesarean section. There was one intrauterine fetal demise, which was secondary to anencephaly. There were three neonatal deaths, two in association with complex congenital heart disease. One twin died outside the neonatal period following cardiac surgery. In total, 28% (7/25) of pregnancies were complicated by major congenital anomalies. There was one case of mild transient twin–twin transfusion syndrome (TTTS). The overall perinatal mortality rate for non-anomalous twins was 2.4% (95% CI?=?0.06%–13.59%).

Conclusions.?Traditionally quoted as up to 80%, perinatal mortality rates <10% for MCMA twins are achievable in contemporary practice. It is vital that these high-risk pregnancies are managed in experienced centers with close surveillance and appropriate pediatric support.     

Velamentous cord insertion in dichorionic and monochorionic twin pregnancies – Does it make a difference?

ObjectiveTo estimate the prevalence of velamentous cord insertion (VCI) in dichorionic (DC) and monochorionic (MC) twins with and without twin-twin transfusion syndrome (TTTS), and to study the associated outcomes.MethodsWe recorded the type of umbilical cord insertion in all consecutive DC and MC placentas examined in two European tertiary medical centers. The association between VCI and perinatal outcomes was estimated and compared.ResultsA total of 1498 twin placentas were included in this study (DC placentas n = 550, MC placentas without TTTS n = 513 and MC placentas with TTTS n = 435). The prevalence of VCI in DC, MC without TTTS and MC with TTTS groups was 7.6%, 34.7% and 36.1%, respectively (P < 0.001). In MC twins (non-TTTS and TTTS groups), VCI was associated with severe birth weight discordance (odds ratio [OR] 4.76 95% CI 2.43, 10.47 and OR 4.52 95% CI 1.30, 28.59, respectively). In MC twins without TTTS, VCI was associated with small for gestational age (OR 1.66, 95% CI 1.12, 2.50). VCI was significantly associated with increased risk of intrauterine fetal demise in MC twins, and this effect was greater in the non-TTTS group (OR 2.71 95% CI 1.38, 5.47). These associations did not occur in DC group. Gestational age at birth was lower in the presence of VCI in the DC and MC twins without TTTS.ConclusionOur findings confirm that the prevalence of VCI is higher in MC twins than in DC twin pregnancies. VCI is an important indicator of adverse perinatal outcome, particularly in MC twins.     

Mode of delivery and neonatal outcome in uncomplicated monochorionic twin pregnancies

Objective: The association between of mode of delivery and perinatal morbidity in monochorionic (MC) twins is not clear. Thus there is no agreement regarding the optimal mode of delivery of MC twins. The aim of this study is to determine the impact of the mode of delivery on neonatal outcome of uncomplicated MC twins in a tertiary center with a strict policy of delivering MC twins by 37 weeks’ gestation. Methods: Retrospective analysis of all uncomplicated MC twin deliveries at a tertiary referral hospital during a 5-year period. Complicated MC pregnancies (fetal death, selective reduction, twin to twin transfusion syndrome, fetal growth restriction of one or both twins or major fetal anomalies) were excluded. Induction of labor or planned caesarean sections of uncomplicated MC pregnancies was conducted between 35 and 37 weeks of gestation. Neonatal outcomes of MC twins were compared according to the mode of delivery. Moreover, mode of delivery was compared with a control group of 1934 dichorionic (DC) twin pregnancies delivered during the same period. Results: The rate of Caesarean section was 63.4% in uncomplicated MC/DA twins pregnancies and this was similar to our rate in DC twins (61%, p = 0.65). Multivariate analysis revealed that adverse neonatal outcome was significantly associated with gestational age at delivery, neonatal birth weight discordance and male gender but not with the intended or actual mode of delivery. Conclusion: Delivering MC twin pregnancies by 37 weeks’ gestation is associated with similar rate of vaginal deliveries compared with DC twin pregnancies. The neonatal outcome was not affected by the mode of delivery, and therefore vaginal delivery seems safe in MC twins.     

Outcome of monochorionic twin pregnancies with abnormal umbilical artery Doppler between 16 and 20 weeks of gestation

Objectives.?To study the perinatal outcome among monochorionic diamniotic (MCDA) twin pregnancies with absent or reversed end-diastolic flow of the umbilical artery (UA-AREDF) at 16–20 weeks of gestation.

Methods.?This was a retrospective study of 84 MCDA twin pregnancies, which were followed up since first trimester in a single obstetric unit. Pregnancies with fetal structural anomalies or genetic syndromes, and those with single intrauterine death before 16 weeks were excluded. The study group was divided into four groups based on the finding of UA-AREDF at the routine follow-up scan at 16–20 week, and the presence of complications at the same time of recruitment. The perinatal outcome between these groups was compared.

Results.?AREDF was present in 56.7% of the 30 monochorionic (MC) twins with complications at recruitment. The mortality was significantly higher among those with AREDF. Among the 54 uncomplicated cases at recruitment, only 7.41% had AREDF. The presence of isolated AREDF was associated with significantly higher incidence of growth discordance (25.0% vs. 2%). The incidence of perinatal mortality and twin-to-twin transfusion syndrome was almost doubled (25.0% vs. 9% and 25.0% vs. 14%).

Conclusions.?AREDF of the umbilical artery is uncommon in normal MC twin in mid-trimester. Once AREDF is present, the perinatal outcome is much worse. Doppler assessment of the umbilical artery should be considered in all MC twin pregnancies for risk assessment.     

Intrauterine fetal death of one twin of diamnionic twins is associated with adverse perinatal outcome of the co-twin

Objective: To determine whether intrauterine fetal death (IUFD) of one twin of diamnionic twins after 22 weeks of gestation is associated with adverse perinatal outcome to the co-twin. Method: A retrospective case-control study (n?=?4070), including all twin births delivered between the years 1988 and 2010, was conducted. Perinatal outcome of the co-twin in diamnionic pregnancies complicated by IUFD were compared with the first twin from a pair of live-born diamnionic twins. A multiple logistic regression model was constructed to determine the association between IUFD of one twin and postpartum death (PPD) of the co-twin while controlling for confounders such as gestational age. Results: Pregnancies complicated with IUFD of a co-twin (n?=?116) had higher rates of adverse perinatal outcomes such as PPD (9.5% vs. 2.3%, p?<?0.001), low Apgar scores (<7) at 1 and 5?min (30.2% vs. 10.6%, p?<?0.001 and 6.9% vs. 1.8%, p?<?0.001, respectively), lower birth weight (1953?±?746?g vs. 2299?±?559?g), and higher rates of preterm birth before 34 weeks of gestation (38.8% vs. 16.4%, p?<?0.001). Using a multivariate analysis with PPD as the outcome variable, mortality was attributed to gestational age (adjusted OR?=?0.58; 95% CI 0.5–0.6, p?<?0.001) and not to the IUFD per se (adjusted OR?=?1.3, 95% CI 0.5–3.3, p?=?0.552). Conclusion: Intrauterine fetal death of one twin (of diamnionic twins) is associated with adverse perinatal outcome of the co-twin mainly due to prematurity.     

Trial of labor after cesarean section in twin pregnancies: Maternal and neonatal safety

Objective.?To assess maternal and perinatal morbidity in patients undergoing a trial of labor after cesarean section (TOLAC) in twin gestations.

Methods.?A retrospective study including all twin pregnancies with a single prior cesarean section was performed. Stratified analysis using a multiple logistic regression model was performed to control for confounders. Patients who had a clear medical indication for a cesarean section (i.e. previous corporeal cesarean section, breech or transverse presentation, placenta previa, placental abruption, and herpes infection) were excluded from the analysis.

Results.?During the years 1988–2007, 134 patients met the inclusion criteria. Of these, 25 patients underwent a trial of labor and the remaining 109 underwent a repeat cesarean delivery. There were no cases of uterine rupture, maternal mortality, or peripartum fever in our population. Higher rates of perinatal mortality were noted in patients undergoing a trial of labor (8% vs. 1.8%, p?=?0.042, OR?=?4.652, 95% CI?=?1.122–19.286). However, a trial of labor was not found to be an independent risk factor for perinatal mortality after controlling for confounders such as gestational age, ethnicity, and fetal malformations (adjusted OR?=?1.07, 95% CI?=?0.07–15.95, p?=?0.95).

Conclusions.?A TOLAC is not associated with an increased risk for maternal morbidity, including uterine rupture. Nevertheless, in our population TOLAC was noted as a risk factor for perinatal mortality, although residual confounding cannot be excluded. Further prospective randomized studies should evaluate the safety of TOLAC in twin gestations to establish appropriate guidelines.     

Prediction of outcome in twin pregnancy with first and early second trimester ultrasound

Abstract

Objective: To establish if first or second trimester biometry is a useful adjunct in the prediction of adverse perinatal outcome in twin pregnancy.

Methods: A consecutive cohort of 1028 twin pregnancies was enrolled for the Evaluation of Sonographic Predictors of Restricted growth in Twins (ESPRiT) study, a prospective study conducted at eight academic centers. Outcome data was recorded for 1001 twin pairs that completed the study. Ultrasound biometry was available for 960 pregnancies. Biometric data obtained between 11 and 22 weeks were evaluated as predictors of a composite of adverse perinatal outcome (mortality, hypoxic ischemic encephalopathy, periventricular leukomalacia, necrotizing enterocolitis, respiratory distress, or sepsis), preterm delivery (PTD) and birthweight discordance greater than 18% (18% BW). Outcomes were adjusted for chorionicity and gestational age using Cox Proportional Hazards regression.

Results: Differences in crown-rump length (CRL) were not predictive of adverse perinatal outcome. Between 14 and 22 weeks, a difference in abdominal circumference (AC) of more than 10% was the most useful predictor of adverse outcome, PTD and 18% or more BW discordance in all twins. Overall the strongest correlation was observed for intertwin differences in biometry between 18 and 22 weeks.

Conclusion: Biometry in the early second trimester can successfully identify twin pregnancies at increased risk. Intertwin AC difference of greater than 10% between 14 and 22 weeks gestation was the best individual predictor of perinatal risk in all twins. Sonographic biometry in the early second trimester should therefore be utilized to establish perinatal risk, thus allowing prenatal care to be improved.     

Is the risk of obstetric anal sphincter injuries increased in vaginal twin deliveries?

Objective: Vaginal twin deliveries have a higher rate of intrapartum interventions. We aimed to determine whether these characteristics are associated with an increased rate of obstetric anal sphincter injuries compared with singleton.

Study design: Retrospective study of all twin pregnancies undergoing vaginal delivery trial was conducted from January 2000–September 2014. Sphincter injury rate compared with all concurrent singleton vaginal deliveries. Multivariable analysis was used to determine twin delivery association with sphincter injuries while adjusting for confounders.

Results: About 717 eligible twin deliveries. Outcome was compared with 33?886 singleton deliveries. Twin pregnancies characterized by a higher rate of nulliparity (54.8% versus 49.5%, p?=?0.005), labor induction (42.7% versus 29.1%, p?<?0.001), and instrumental deliveries (27.5% versus 16.7%, p?<?0.001), lower gestational (34.6?±?3.3 versus 38.8?±?2.3, p?<?0.001), and lower birth weight. Total breech extraction was performed in 29.0% (208/717) of twin deliveries. Overall obstetric sphincter injury rate was significantly lower in the twins group (2.8% versus 4.4%, p?=?0.03, OR?=?0.6, 95% CI 0.4–0.9), due to lower rate of 3rd degree tears in twins versus singletons (2.2% versus 4.0%, p?=?0.02), rate of 4th degree tears similar among the groups (0.6% versus 0.4%, p?=?0.5). In multivariable analysis, sphincter injuries were associated with nulliparity (OR?=?3.9, 95% CI 3.4–4.5), forceps (OR?=?6.8, 95% CI 5.8–7.8), vacuum (OR?=?2.9, 95% CI 2.5–3.3), earlier gestational age (OR?=?0.2, 95% CI 0.1–0.3), episiotomy (OR?=?0.8, 95% CI 0.7–0.9), and birth weight over 3500?g (OR?=?1.8, 95% CI 1.6–2.0). However, the association between twins (versus singletons) deliveries and sphincter injuries was lost after adjustment for delivery gestational age (OR?=?0.7, 95% CI 0.4–1.2).

Conclusion: Despite a higher rate of intrapartum interventions, the rate of sphincter injuries is lower in twins versus singleton deliveries, mainly due to a lower gestational age at delivery.     

Preeclampsia in twin pregnancies: association with selective intrauterine growth restriction

Objective: To identify the association between preeclampsia (PE) and selective intrauterine growth restriction (sIUGR) in twin pregnancies.

Methods: This was a retrospective cohort study of 1004 twin pregnancies from 2008 to 2014. We specifically compared the incidence, clinical characteristics and outcomes of PE between sIUGR and normal-growth twin pregnancies.

Results: PE occurred more frequently in sIUGR pregnancies [29.0% (51/176)] than in normal-growth twin pregnancies [13.1% (99/756), p?<?0.001, adjusted odds ratio 3.29]. Among sIUGR, the incidence of PE was significantly higher in dichorionic (DC) pregnancies (37.5%, 30/80) than in monochorionic (MC) pregnancies (21.9%, 21/96). The rates of onset at <32 weeks (p?=?0.045) and of severe PE (p?=?0.025) were higher in sIUGR pregnancies with PE. The systolic blood pressure was also higher in sIUGR pregnancies with PE (152.6?±?11.8?mmHg) than in normal-growth pregnancies with PE (148.0?±?8.2?mmHg) (p?=?0.042). Additionally, more sIUGR pregnancies were delivered at 32–36 weeks (p?=?0.001), and fewer were delivered at ≥36 weeks (p?<?0.001). Moreover, the prevalence of severe neonatal asphyxia was higher in sIUGR pregnancies with PE than in normal-growth pregnancies with PE (8.8% versus 2.5%, p?=?0.020).

Conclusions: sIUGR is associated with increased odds of developing severe PE in twin pregnancies, leading to poorer perinatal outcomes.     

The natural history of preterm premature rupture of membranes in twin pregnancies

Objective: To compare the characteristics of preterm premature rupture of membranes (PPROM) between twin and singleton pregnancies.

Methods: This was a retrospective study of all women with twin and singleton pregnancies admitted with PPROM between 24–34 weeks of gestation.

Results: Overall 698 women with PPROM were eligible for the study: 101 (14.5%) twins and 597 (85.5%) singletons. Twins presented with PPROM at a more advanced gestational age compared with singletons (29.1?±?2.7 vs. 28.5?±?2.8 weeks, p?=?0.03). The latency period was shorter in twins compared with singletons, especially for women presenting after 28 weeks of gestation (5.0?±?0.8 vs. 7.0?±?0.4 days, p?=?0.01). Women with twins were more likely to deliver within 48?h (OR:?2.7; 95%CI: 1.7–4.2) and were less likely to deliver within 2–7 days (OR: 0.5; 95%CI: 0.3–0.9) following PPROM. The rate of clinical chorioamnionitis or placental abruption following PPROM was lower in twins compared with singletons (15.8% vs. 26.0%, p?=?0.03).

Conclusions: PPROM in twin pregnancies tends to occur at a more advanced gestational age, is associated with a shorter latency period and is less likely to be complicated by chorioamnionitis or placental abruption compared with singletons. This information may be useful for counseling and management decisions in cases of PPROM in women with twins.     

Neonatal outcome of late preterm uncomplicated monochorionic twins: what is the optimal time for delivery?

Objective: To determine the neonatal outcome at late prematurity of uncomplicated monochorionic (MC) twin pregnancies.

Methods: A retrospective cohort study of 166 patients with uncomplicated MC diamniotic twins delivered between 34 and37 weeks of gestation at a single tertiary center. The study population was classified into four groups according to the gestational age at delivery: (1) 34 weeks, (2) 35 weeks, (3) 36 weeks and (4) 37 weeks. Neonatal outcome measures were compared between the groups.

Results: Neonatal morbidity was significantly higher at 34 weeks of gestation compared to the other three groups including respiratory distress syndrome, oxygen requirement, hypothermia and hyperbilirubinemia. Moreover, the rate of admission to the special care unit and need for phototherapy were significantly higher in newborns born at 36 weeks compared to 37 weeks of gestation (p?=?0.02 and 0.03 respectively). Multiple regression analysis revealed that the risk for adverse neonatal outcome was significantly associated with gestational age at delivery. Of note, there were no fetal or neonatal deaths in our cohort.

Conclusions: The risk of neonatal morbidity of uncomplicated MC twins delivered at 34–37 weeks of gestation significantly decreases with advanced gestation. Therefore, under close fetal surveillance, uncomplicated MC twin pregnancies should be delivered at 37 weeks of gestation.     

The impact of assisted reproductive technology and chorionicity in twin pregnancies complicated by obstetric cholestasis

Objective: To assess in a cohort of twin pregnancies the prevalence of obstetric cholestasis (OC) and its correlation with the type of conception and chorionicity.

Methods: A retrospective cohort study including all the twin pregnancies delivered between 2005 and 2013 at our University Hospital was carried out. In the study population, the prevalence of OC was investigated in relationship to the impact of assisted reproductive technology (ART) and of chorionicity.

Results: Overall, 569 twin pregnancies were included in the study population. Among those complicated by OC, the rate of ART was 3-fold higher (OR 3.4, 95% CI 1.2–9.5, p?=?0.02), whereas the rate of dichorionicity did not differ significantly (OR 1.6, 95% CI 0.3–7.9, p?=?0.53).

Conclusion: The risk of developing OC seems to be significantly higher among twin pregnancies obtained after ART in comparison with those conceived spontaneously.     

Risk factors for intrauterine fetal death (1988–2009)

Objective.?To determine risk factors for intrauterine fetal death (IUFD).

Study design.?A retrospective population-based study, of all singleton deliveries between the years 1988–2009 was conducted. Intrapartum deaths, postpartum death, and multiple gestations were excluded. A multiple logistic regression model was used to determine independent risk factors.

Results.?During the study period, out of 228,239 singleton births, 1694 IUFD cases were recorded (7.4 per 1000 births). The following independent risk factors were identified in the logistic regression executed: Oligohydramnios (OR 2.6, 95% CI 2.1–3.2, p-value?<?0.001), polyhydramnios (OR 1.8, 95% CI 1.4–2.2, p-value?<?0.001), previous adverse perinatal outcome (OR 1.7, 95% CI 1.5–2.1, p-value?<?0.001), congenital malformations (OR 2.0, 95% CI 1.8–2.3, p-value?<?0.001), true knot of cord (OR 3.7, 95% CI 2.8–4.9, p-value?<?0.001), meconium stained amniotic fluid (OR 2.7, 95% CI 2.3–3.0, p-value<0.001), placental abruption (OR 2.9, 95% CI 2.4–3.5, p-value?<?0.001), advanced maternal age (OR 1.03, 95% CI 1.02–1.04, p-value?<?0.001), and hypertensive disorders (OR 1.24, 95% CI 1.0–1.4, p-value?=?0.026). Jewish ethnicity (versus Bedouin – OR 0.64, 95% CI 0.57–0.72, p-value?<?0.001), gestational diabetes (OR 0.7, 95% CI 0.5–0.8, p-value?=?0.001), previous cesarean section (OR 0.8, 95% CI 0.7–0.97, p-value?=?0.019), and recurrent abortions (OR 0.8, 95% CI 0.6–0.9, p-value?=?0.011) were negatively associated with IUFD.

Conclusion.?Several independent risk factors were identified, suggesting a possible cause of death. Other pathologic conditions that facilitate tighter pregnancy surveillance and active management were found protective, pointing the benefit of such management approaches in high-risk pregnancies.     

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.     

Perinatal outcomes with intrahepatic cholestasis of pregnancy in twin pregnancies

Objective: To describe perinatal outcomes of twin pregnancies complicated by intrahepatic cholestasis of pregnancy (ICP).

Methods: We conducted a retrospective cohort study of women delivered at a large tertiary obstetric center in Shanghai, China from January 2006 to May 2014. Delivery data were abstracted from medical records of all twin gestations delivered at the hospital.

Results: A total of 129/1922(6.7%) twin and 1190/92?273 singleton (1.3%) pregnancies were complicated by ICP. An increased risk of stillbirth among twin pregnancies was observed (3.9% and 0.8% in the ICP and non-ICP groups, respectively; aOR 5.75, 95% CI 2.00–16.6). Stillbirths with ICP and twins occurred between 33 and 35 weeks gestation compared to 36–38 weeks gestation among singletons. ICP in twins was also associated with an increased risk of preterm birth (<37 weeks) with an aOR of 4.17 (95% CI 2.47–7.04) and an aOR of 1.89 (95% CI 1.26–2.85) for delivery <35 weeks. Twin pregnancies complicated by ICP also had increased meconium staining of amniotic fluid and lower birth weight.

Conclusions: Twin pregnancies with ICP have significantly increased risks of adverse perinatal outcomes including stillbirth and preterm birth. Stillbirth occurs at an earlier gestational age in twin gestation compared to singletons, suggesting that earlier scheduled delivery should be considered in these women.     

The effect of maternal anemia on maternal and neonatal outcomes in twin pregnancies

Objective: The objective of this study is to investigate the effect of second trimester anemia on maternal and perinatal outcomes in twin pregnancies.

Methods: A retrospective population-based study was conducted, comparing maternal and neonatal outcomes in women carrying twins, with second trimester anemia (defined as hemoglobin?<?10?g/dl) to those without anemia (defined as hemoglobin?>?or equal to 10?g/dl). Deliveries occurred in a tertiary medical center in 2013.

Results: During the study period, there were 307 twin deliveries. Hemoglobin levels were available for 247 (80.4%) twins; 66 (26.7%) of these had anemia (<10?g/dl) during the second trimester. Women with second trimester anemia had a higher parity (p=?0.03), and needed more blood transfusions than those with hemoglobin level >?or equal to 10?g/dl (OR?=?1.6; 95% CI 1.11–2.43, p?<?0.001). No significant differences were noted between the groups regarding other obstetrical outcomes or regarding perinatal outcomes.

Conclusion: Second trimester anemia in women carrying twins is associated with a high parity and increases the risk for blood transfusions. However, in our population, maternal anemia in twin gestations does not increase the risk for adverse perinatal outcome.