Impact Of Chorionicity Research Articles

The Impact of Chorionicity on Pregnancy Outcome and Neurodevelopment at 2 Years Old Among Twins Born Preterm: The EPIPAGE-2 Cohort Study

(Abstracted from BJOG 2021;128:281–291) Overall, as many as 60% of twins are born preterm, and are therefore at risk for neonatal and long-term complications. Some evidence has shown that outcomes for preterm twins differ by chorionicity-monochorionic (MC) versus dichorionic (DC).

The impact of chorionicity and assisted reproductive therapies in obstetric and neonatal outcomes

Objective Multiple gestations’ incidence have raised worldwide in the last years, much due to assisted reproductive therapies (ART). The goal of this study was to analyze obstetric and neonatal outcomes of twin pregnancies in a level 3 maternity. Methods A retrospective study including all twins born in a period of 12 years in a level 3 maternity was conducted. Analysis comparing spontaneous monochorionic and dichorionic twins and spontaneous and ART dichorionic twins were performed. A p value < .05 was considered statistically significant. Results The sample included 1783 newborns from 875 mothers. Mean maternal age was 31 years, with 616 spontaneous pregnancies and 259 through ART. Prematurity occurred in 77%. Congenital malformations were found in 6%, and the mortality rate was 3%. Monochorionic twins had higher prematurity (79% vs 72%) and very low birthweight (VLBW) rate (19% vs 14%). Congenital anomalies (9% vs 6%), Respiratory Distress Syndrome (23% vs 18%), patent ductus arteriosus (7% vs 4%), anemia (11% vs 5%), periventricular hemorrhage (5% vs 3%), mechanical ventilation (16% vs 10%) and mortality (4% vs 2%) were higher in monochorionic twins. Although congenital malformations were more frequent in the ART group, the difference was not statistically significant. The effect of ART in neonatal and obstetric outcomes was related to maternal age. Conclusion Monochorionic pregnancies were associated with worst obstetric and neonatal outcomes. Although congenital malformations were more frequent in the ART group, the difference was not statistically significant. Most obstetric and neonatal complications were related to advanced maternal age.

The impact of chorionicity on pregnancy outcome and neurodevelopment at 2 years old among twins born preterm: the EPIPAGE-2 cohort study.

To compare the short- and mid-term outcomes of preterm twins by chorionicity of pregnancy. Prospective nationwide population-based EPIPAGE-2 cohort study. 546 maternity units in France, between March and December 2011. A total of 1700 twin neonates born between 24 and 34weeks of gestation. The association of chorionicity with outcomes was analysed using multivariate regression models. First, survival at 2-year corrected age with or without neurosensory impairment, and second, perinatal, short-, and mid-term outcomes (survival at discharge, survival at discharge without severe morbidity) were described and compared by chorionicity. In the EPIPAGE 2 cohort, 1700 preterm births were included (850 twin pregnancies). In all, 1220 (71.8%) were from dichorionic (DC) pregnancies and 480 from monochorionic (MC) pregnancies. MC pregnancies had three times more medical terminations than DC pregnancies (1.67 versus 0.51%, P<0.001), whereas there were three times more stillbirths in MC than in DC pregnancies (10.09 versus 3.78%, P<0.001). Both twins were alive at birth in 86.6% of DC pregnancies compared with 80.0% among MC pregnancies (P=0.008). No significant difference according to chorionicity was found regarding neonatal deaths and morbidities. Likewise, for children born earlier than 32weeks, the 2-year follow-up neurodevelopmental results were not significantly different between DC and MC twins. This study confirms that MC pregnancies have a higher risk of adverse outcomes. However, the outcomes among preterm twins admitted to neonatal intensive care units are similar irrespective of chorionicity. Monochorionicity is associated with adverse perinatal outcomes, but outcomes for preterm twins are comparable irrespective of their chorionicity.

EP21.30: The impact of chorionicity on perinatal and neonatal outcomes in diamniotic twin pregnancies after a normal 18–24‐week scan

EP21.30: The impact of chorionicity on perinatal and neonatal outcomes in diamniotic twin pregnancies after a normal 18–24‐week scan

The impact of chorionicity and the type of twin growth on the early neonatal outcome in twin pregnancies – 20 years of experience from one tertiary perinatal center

ObjectiveTwin pregnancies are associated with higher neonatal mortality and morbidity. Growth discordance and monochorionicity are among the factors that worsen the course of pregnancy. The study aimed to assess neonatal conditions and mortality in relation to growth type and chorionicity. Materials and methodsData from 820 pregnant women with twin pregnancies and their 1640 newborns were analyzed. The Apgar score and umbilical artery blood pH, as well as the rate of complications, were compared between dichorionic diamniotic (DCDA) and monochorionic diamniotic (MCDA) twins with symmetric and discordant growth. The Student's t-test and the Pearson chi-square test were used for comparisons. ResultsThere were 576 (70.2%) DCDA pregnancies, including 421 (73.1%) with symmetric growth and 155 (26.9%) with discordant growth, and 244 (29.8%) MCDA pregnancies, including 110 (45.1%) with symmetric growth and 134 (54.9%) with discordant growth. A significantly greater percentage of twins with discordant growth occurred in women older than 34 years than in those that were younger. An Apgar score of ≤7 was significantly more common among MCDA discordant twins, while an arterial umbilical blood pH of <7.2 was more common among MCDA twins with symmetric growth. Early neonatal deaths (n = 29; 1.8%), respiratory disorders, and a birth weight of <1500 g were significantly more common in MCDA twins than in DCDA twins. ConclusionMCDA twins with growth discordance are burdened with a higher risk of neonatal morbidity and mortality than symmetric DCDA twins. Chorionicity and growth discordancy are important determinants of the outcome of twin pregnancy.

The impact of chorionicity on maternal and fetal outcomes

The impact of chorionicity on maternal and fetal outcomes

The impact of chorionicity and type of conception on maternal-neonatal outcome in twin pregnancies

To evaluate the maternal and neonatal outcomes in twin pregnancies according to chorionicity (monochorionic (MC) versus dichorionic (DC) and type of conception [spontaneously conceived (SC) versus assisted reproduction technology (ART)]. A retrospective study of 196 twin pregnancies admitted to the Department of Gynecology, Obstetrics and Urology of the University of Rome Sapienza, from January 2008 to April 2013. There were 55 MC and 141 DC twin pregnancies (82 SC and 59 ART). MC twin pregnancies had a higher incidence of preterm birth (p < 0.008), twin-twin transfusion syndrome (TTTS) (p < 0.021), and intrauterine growth restriction (IUGR) (p < 0.05). MC pregnancies had lower neonatal birth weight (p < 0.05), and lower Apgar score. ART DC pregnancies had a higher incidence of preterm delivery (p < 0.05). MC twin pregnancy is associated with higher risk of adverse maternal and perinatal outcomes. In the DC subgroup, ART is associated to a higher incidence of preterm delivery.

The impact of chorionicity on maternal pregnancy outcomes

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. 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. 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). 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.

Effect of advanced maternal age on perinatal outcomes in twins: the impact of chorionicity

PurposeIn contrast to singletons, twins born to older mothers have lower rates of perinatal mortality than twins born to younger mothers. We examined whether differences in chorionicity could explain this unexpected maternal age effect. MethodsWe used population-based data on twins born to mothers aged 20–29 (n = 3702) and ≥35 years (n = 1880) in the North of England, UK, 1998–2007. We calculated rate ratios (RR) and 95% confidence intervals (CIs) to estimate the effect of maternal age; adjusted RRs (ARRs) were estimated by the use of generalized estimating equations for Poisson regression controlling for chorionicity and other confounders. ResultsOlder mothers had a lower proportion of monochorionic twins (17.6% vs. 24.3%, P < .01); lower neonatal (RR, 0.57; 95% CI, 0.34–0.95) and perinatal mortality (RR, 0.74; 95% CI, 0.53–1.04). Adjustment for chorionicity attenuated these associations (ARR, 0.59; 95% CI, 0.35–0.98 and ARR, 0.80; 95% CI, 0.57–1.12, respectively) and after further adjustment for additional factors, both associations became nonsignificant. Older mothers had greater rates of small-for-gestational-age infants (ARR, 1.59; 95% CI, 1.24–2.05), and cesarean delivery (ARR, 1.31; 95% CI, 1.16–1.48). ConclusionsPerinatal death rates were lower but not statistically different for twins born to older versus younger mothers. This association was attenuated by adjustment for chorionicity.

Impact of chorionicity on first‐trimester nuchal translucency screening in ART twin pregnancies

Nuchal translucency (NT) measurement in assisted reproduction treatment (ART) twins is less extensively investigated. Therefore, the present study compared NT measurements of spontaneously conceived twins with ART twins in dichorionic (DC) and monochorionic (MC) pregnancies. Retrospective analysis of 706 unaffected twins between 11 + 0 and 13 + 6 weeks conceived either spontaneously (n = 362) or with ART (n = 344). The group with spontaneous conception included 234 DC (64.6%) and 128 MC (35.4%) pregnancies. In the ART group, 326 were DC (94.7%) and 18 were MC (5.3%). NT values were transformed into multiples of median (MoM). In the DC group, no significant differences between ART and spontaneously conceived twins (NT MoM 1.06 ± 0.28 vs 1.03 ± 0.29; p > 0.05) were observed. NT MoM of MC ART twins was higher compared with spontaneous MC twins (1.23 ± 0.82 vs 0.99 ± 0.27; p = 0.011). Although the incidence of twin-to-twin transfusion syndrome (TTTS) was higher among ART twins (11.1% vs 4.7%), inter-twin NT difference was similar between pregnancies with TTTS (0.42 ± 0.21) or without (0.40 ± 0.71). Measurement of NT thickness in DC ART twins achieves comparable results with twins conceived spontaneously. Conclusions in MC twins are limited; however, higher NT MoM was not related to TTTS or selective intrauterine growth restriction.

Impact of chorionicity on risk and timing of intrauterine fetal demise in twin pregnancies

We sought to estimate the association between chorionicity and intrauterine fetal demise (IUFD) of one or both fetuses in twin pregnancies. In a retrospective cohort of twins undergoing anatomic survey, risk of IUFD in monochorionic and dichorionic twins was compared. The primary outcome was IUFD of one or both fetuses; secondary outcomes included nonanomalous fetal deaths. Of 2161 twin pregnancies meeting inclusion criteria, 86 had at least 1 IUFD and 32 experienced a double fetal loss. Monochorionic pregnancies had an increased risk of a single demise (adjusted odds ratio, 1.69; 95% confidence interval, 1.04-2.75) and a double demise (adjusted odds ratio, 2.11; 95% confidence interval, 1.02-4.37). Of all double demises, 70% occurred <24 weeks. Monochorionic twins carry an increased risk of fetal death compared to dichorionic twins. Double demise occurs primarily <24 weeks, regardless of chorionicity.

Amniocentesis in twin pregnancies: a systematic review of the literature

Using published data, we sought to determine the amniocentesis-related loss rate in twin gestations. We searched the PUBMED database using keywords "amniocentesis", "twin" and "twins" to identify articles evaluating genetic amniocentesis in twin gestations published from January 1970 to December 2010. Random effects models were used to pool procedure-related loss rates from included studies. The definition of "loss" varied across the 17 studies identified (Table 1). The pooled procedure-related loss rate at < 24 weeks was 3.5% (95% confidence interval [CI] 2.6-4.7) (Figure 2). Pooled loss rates at < 28 weeks (Figure 4) and to term (Figure 5) could not be calculated due to unacceptable heterogeneity of available data. Seven studies included a control (no amniocentesis) group and reported a pooled odds ratio for total pregnancy loss among cases of 1.8 (95% CI 1.2-2.7) (Figure 3). Only 1 study reported procedure-related loss rates by chorionicity (7.7% among monochorionics vs 1.4% among controls; p 0.02). Analysis of published data demonstrated a pooled amniocentesis-related loss rate of 3.5% in twin gestations < 24 weeks. Pooled loss rates within other post-amniocentesis intervals or other gestational age windows and the impact of chorionicity on procedure-related loss rates cannot be determined from published data.

Ultrasound evaluation of the multifetal gestation

With the increasing incidence of multifetal gestations, it is essential for the clinician to appreciate the benefit of ultrasound evaluation in these pregnancies. Multifetal gestation pregnancies are at increased risk for a range of both antepartum and intrapartum complications, such as intrauterine growth restriction, premature delivery, congenital anomalies, cord accidents, malpresentations, placenta previa, and abruptio placentae. First-trimester ultrasonic evaluation, amniotic fluid assessment, monitoring of fetal growth, diagnosing the twin-to-twin transfusion syndrome, and assessment of fetal anomalies will be reviewed. An early and accurate assessment of amnionicity and chorionicity are paramount in these gestations. The impact of chorionicity, in particular, can have profound consequences in the management of multifetal gestations. The determination of chorionicity onultrasonic evaluation in a multifetal gestations. The determination of chorionicity on ultrasonic evaluation in a multifetal pregnan...

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.

Second-trimester Down syndrome maternal serum screening in twin pregnancies: impact of chorionicity.

To evaluate the diagnostic value of second-trimester maternal serum screening for Down syndrome in twin pregnancies. On the basis of a prospective study of second-trimester maternal serum screening, we studied the distribution of alpha-fetoprotein (AFP) and free ss hCG in 3043 twin pregnancies with known outcome. There were 1561 dichorionic and 244 monochorionic pregnancies. The placental type was not available in 1238 cases. We compared 5 screening policies with the same risk, 1/250, cut-off: maternal age, maternal age corrected for the risk of having at least one affected twin in dichorionic pregnancies, maternal serum marker screening using observed AFP and free ss-hCG values divided by a factor of 2, by using the median values actually observed in the global twin population, or by the median values specific to mono- or dichorionic twins. When expressed in singleton-derived MoMs, the median was 2.10 for AFP and 2.11 for free ss-hCG. The median AFP did not differ between monochorionic and dichorionic pregnancies. The distribution of free ss-hCG was significantly shifted towards greater values in monochorionic (2.16 MoM) compared to dichorionic (2.07) pregnancies (p < 0.0001). Screened-positive and detection rates were, respectively, 6.6% and 27.3% using maternal age alone, 24.6% and 54.5% using maternal age corrected for the risk of having at least one affected twin in dichorionic pregnancies, 7.75% and 54.5% using observed AFP and free beta-hCG values divided by a factor of 2, 8.05% and 54.5% using the median values actually observed in the global twin population, and 7.75% and 54.5% using the median values specific to mono- or dichorionic twins. Trisomy 21 second-trimester maternal serum screening is feasible in twins, and is better than a policy based on maternal age alone.