Chorionicity In Twin Pregnancies Research Articles

Can maternal serum midkine level predict chorionicity in twin pregnancies?

Sometimes it can be difficult to chorionicity determination in twin pregnancies. This study aimed to compare maternal serum midkine levels between twin and singleton pregnancies. We also evaluated the relationship between chorionicity and maternal serum midkine level in twin pregnancies. The present prospective cohort study included 16 patients with monochorionic diamniotic twin pregnancies, 38 with dichorionic diamniotic twin pregnancies, and 66 healthy singleton pregnancies admitted to Ankara City Hospital Perinatology Clinic between June 2021 and June 2022. Demographic features, clinical characteristics, and serum midkine levels were compared between the groups. Additionally, a receiver operator characteristics (ROC) analysis was performed to assess the performance of midkine for detecting chorionicity. The median maternal serum midkine level was found to be 0.64 ng/ml in twin pregnancies and 0.26 ng/ml in singleton pregnancies (p < 0.001). When twin pregnancies were compared in terms of chorionicity, serum midkine level was determined as 1.20 ng/ml in the monochorionic diamniotic group and 0.50 ng/ml in the dichorionic diamniotic group (p = 0.034). An optimal cut-off value of 1.03 ng/ml was found for the determination of chorionicity (AUC: 0.68, p = 0.03, 95% CI: 0.53–0.83, %56.3 sensitivity, 76.3% specificity). In advanced weeks of pregnancy, biomarkers can be used as helpful parameters for ultrasonography in the diagnosis of twin pregnancies. Maternal serum midkine levels might be used to determine chorionicity in equivocal cases.

Introducing a New Predictor of Chorionicity in the Second and Third Trimesters: The “Cleft Sign”

Objective: The aim of this study was to suggest a new sonographic sign, which could be helpful in the determination of chorionicity in twin pregnancies, during the second and third trimesters. Materials and Methods: This was a retrospective study evaluating the sonographic images of 50 women with twin pregnancy. Out of 50 twin pregnancy case reviewed, only 27 were included. Those patient cases that were included were scanned by a single radiologist. The presence of a hypoechoic cleft, in the thickness of placental bulk, could be detected in all of the dichorionic pregnancy cases. This sonographic appearance was referred to as the “cleft sign.” Results: The “cleft sign” was present in all the dichorionic diamniotic (DC-DA) twin pregnancy cases, but no similar appearance was seen in the monochorionic diamniotic (MC-DA) twins. Considering this sign, the radiologist was able to correctly diagnose the chorionicity of all 24 patients in the second and third trimester. Conclusion: The findings of the present study suggest a possible role for this newly identified “cleft sign.” This sonographic appearance is a hypoechoic cleft in the thickness of placenta, of dichorionic pregnancies, as an indicator of DC twin pregnancy. In this retrospective case analysis, the “cleft sign” was diagnostically significant in the second and third trimesters.

Association between chorionicity and preterm birth in twin pregnancies: a systematic review involving 29 864 twin pregnancies

The perinatal mortality and morbidity among twins vary by chorionicity. Although it is considered that monochorionicity is associated with an increased risk of preterm birth in twin pregnancies, no systematic review exists evaluating this association. This systematic review was undertaken to assess the association between preterm birth and chorionicity in twin pregnancies. We searched the electronic databases from January 1990 to July 2019 without language restrictions. All studies on twin pregnancies where chorionicity and preterm birth were evaluated were included. Findings are reported as odds ratios with 95% confidence intervals. The estimates are pooled using random-effects meta-analysis. From 13156 citations, we included 39 studies (29864 pregnancies). Monochorionicity was significantly associated with increased risk of preterm birth at ≤28, ≤32, ≤34 and <37weeks in women asymptomatic and symptomatic for preterm labour (odds ratio [OR] 2.14, 95% CI 1.52-3.02, I2 =46%, OR 1.55, 95% CI 1.27-1.89 I2 =68%, OR 1.47, 95% CI 1.27-1.69, I2 =60%, OR 1.66, 95% CI 1.43-1.93, I2 =65%, respectively). Among those asymptomatic for preterm labour, significantly increased odds of preterm birth were seen for monochorionicity at gestations ≤34weeks (OR 1.85, 95% CI 1.42-2.40, I2 =25%) and <37weeks (OR 1.75, 95% CI 1.22-2.53, I2 =61%). Sensitivity analysis showed significantly increased odds of spontaneous preterm birth at ≤34 and <37weeks for monochorionicity (OR 1.25, 95% CI 1.01-1.55, I2 =0% and OR 1.41, 95% CI 1.13-1.78, I2 =0%). Monochorionicity is significantly associated with preterm birth at all gestations. In twin pregnancies, monochorionicity is associated with an increased risk of preterm birth at all gestations.

VP44.14: Maternal and fetal characteristics based on mode of chorionicity in twin pregnancies

VP44.14: Maternal and fetal characteristics based on mode of chorionicity in twin pregnancies

Preterm and term birth in twin pregnancies during a seven-year period: a call for obstetricians to declare about amnionicity and chorionicity.

Aim To compare maternal, foetal and neonatal characteristics, and perinatal outcome of preterm and term deliveries in twins pregnancies in order to improve perinatal care in Bosnia and Herzegovina. Methods This retrospective cohort study included pregnant women with twin pregnancy who delivered during the period between 1 January 2012 and 31 December 2018 at the Clinic for Gynaecology and Obstetrics, University Clinical Centre Tuzla. Results During the seven-year period 26 734 deliveries were recorded, out of which 362 (1.35 %) were twin pregnancies, 226 (62.4%) preterm and 136 (37.5%) term ones. In the preterm group 38 (16.8%) pregnancies were assisted medical reproduction, and 16 (11.7%) of those were in the term group. The average birth weight was significantly higher for the first twin in both groups (p<0.00001). Incipient intrauterine foetal asphyxia was more frequent in the preterm group (p<0.05). The most common indication for Caesarean section was abnormalities of foetal presentation and lie, 176 (68.2%) for the overall sample. Conclusion Cornerstone of twin pregnancy antenatal care is to get correct data about amnionicity and chorionicity. Since majority of prenatal data did not have this information we call all obstetricians to declare about amnionicity and chorionicity in twin pregnancies during the first trimester ultrasound examination.

OP07.09: Accuracy of second and third trimester ultrasound in determining chorionicity in twin pregnancies

OP07.09: Accuracy of second and third trimester ultrasound in determining chorionicity in twin pregnancies

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.

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.

OP18.01: Prevalence of pre‐eclampsia according to zygosity and chorionicity in twin pregnancy

<scp>OP</scp>18.01: Prevalence of pre‐eclampsia according to zygosity and chorionicity in twin pregnancy

Determination of Chorionicity in Twins: Feasibility at a Tertiary Care Centre and Audit of Current Practice in the Community

AbstractTo assess the feasibility and to audit the practice of determining chorionicity in twin pregnancies in South India. Sonographic findings from first trimester scans of twin pregnancies were retrospectively analysed to evaluate the feasibility of determining chorionicity in the first visit to the unit. In addition, an audit was carried out on all twin pregnancies referred to the authors in the second trimester to ascertain whether chorionicity had been established prior to referral. It was feasible to determine chorionicity at the first visit in 100 % of the 611 twin pregnancies that were seen at 11–14 weeks in the unit. However, the audit revealed that only 40 % of the referred population had a diagnosis of chorionicity prior to referral. Whilst it is feasible to determine chorionicity in all twin pregnancies in the first trimester, the practice is not widespread in the referring community in South India and this needs to be addressed.

Umbilical Artery Doppler Ultrasound for the Determination of Chorionicity in Twin Pregnancies

Background: Maternal and perinatal complications are higher in twins than in singleton pregnancies. This complications rate is directly related to placental chorionicity in twin pregnancies. Early diagnosis of twins and their chorionicity is necessary to reduce the perinatal mortality. It can be determined by different methods in the first trimester. Ultrasonography is a valuable tool in management of twin pregnancy. Ultrasound in evaluation of the chorionicity decreases later in gestational weeks. The aim of this study is to determine the chorionicity by using Doppler ultrasonography in second and third trimesters. Methods: Patients were divided into two groups according to their chorionicity. Pregnancies with dichorionic placentas were included into group 1, while with monochorionic placentas were included into group 2. In both groups, PI, RI and S/D indices of umbilical artery were measured in each fetus. Whether there is a significant difference between the groups in the Doppler parameters was evaluated. Results: The PI, RI and S/D indices of umbilical artery doppler ultrasonography were different between the twins with dichorionic placentas (p < 0.05), but they were similar in twins with monochorionic placentas. Conclusions: Based on our study results, we suggest that the Doppler ultrasonography can be useful method for chorionicity determination of twin pregnancies at second and third trimesters, if chorionicity has not determined until the end of second trimester. doi:10.4021/ jcgo29w

Umbilical Artery Doppler Ultrasound for the Determination of Chorionicity in Twin Pregnancies

Umbilical Artery Doppler Ultrasound for the Determination of Chorionicity in Twin Pregnancies

First‐trimester ultrasound determination of chorionicity in twin pregnancy

To determine the accuracy of ultrasound at 11-14 weeks' gestation in the diagnosis of chorionicity in twin pregnancy. This was a retrospective observational study of data obtained between 1999 and 2010. At the first-trimester routine ultrasound scan, chorionicity was assigned according to the number of placental masses and T or λ-signs for a single placental mass. Chorionicity was confirmed by histology or discordant sex at birth. A total of 648 pregnancies were assigned chorionicity by first-trimester ultrasound during the study period. Chorionicity was ascertained in 613 cases, either by histology (n = 340) or discordant sex (n = 273). Chorionicity was correctly assigned by ultrasound at 11-14 weeks in 612 of 613 pregnancies (accuracy 99.8%). Sensitivity and specificity for determining monochorionicity were 100% and 99.8%, respectively. First-trimester ultrasound can be used to determine chorionicity reliably by noting the number of placental masses and T or λ-signs. Determination of twin chorionicity is important and should be completed in the first trimester.

The Frequency and Clinical Significance of Twin Gestations According to Zygosity and Chorionicity

Although the clinical importance of chorionicity in twin pregnancies has been studied widely, the significance of perinatal determination of zygosity using molecular genetic analyses remains controversial. The purpose of this study was to determine the frequency and clinical significance of twin gestations according to zygosity and chorionicity in a Korean population. We enrolled 569 women who delivered twin newborns (> 24 weeks) at Seoul National University Hospital between 1999 and 2008. Chorionicity was established by histologic examination of placentae. Zygosity was determined with sex of neonates, chorionicity, and DNA analysis of umbilical cord blood. The frequency of dizygotic (DZ) twins was 71.0% (404/569 pairs) based on the opposite sex (238/404 [58.9%]) and DNA analyses (166/404 [41.1%]); that of monozygotic (MZ) twins was 29.0% (165/569), including monochorionic (MC) (72.1% [119/165]) and dichorionic (DC) twins (27.9% [46/165]), which was confirmed by DNA analyses. Among spontaneously conceived twins, the frequency of MZ twins was more than twice that of DZ twins. The risk of low birth weight was 1.8-fold higher among MZDC twins and 1.9-fold higher among MZMC twins than among DZDC twins (p < .05). Bronchopulmonary dysplasia occurred more frequently among MZMC twins than among DZDC twins (adjusted OR 8.42, 95% CI 1.82-39.08, p < .01). However, the frequencies of other neonatal morbidities were not significantly higher in the MZMC group than in the MZDC and DZDC groups. The perinatal mortality rate was 15 per 1000 total births in the DZDC twins, 20 per 1000 total births in the MZDC and 56 per 1000 total births in the MZMC (p < .01). Although monozygosity was shown to be a risk factor for perinatal death and accurate determination of zygosity plays a great role in the future consideration of organ transplantation and twin studies, the value of zygosity determination along with chorionicity in relation to overall neonatal morbidity was not definite.

Medians and correction factors for biochemical and ultrasound markers in Chinese women undergoing first‐trimester screening for trisomy 21

To establish normative values and distribution parameters of first-trimester maternal serum free beta-human chorionic gonadotropin (beta-hCG), pregnancy-associated plasma protein-A (PAPP-A) and fetal nuchal translucency (NT) thickness in Chinese women and to examine the effects of covariates on their levels. Maternal serum free beta-hCG, PAPP-A and fetal NT were measured in 9762 women presenting for first-trimester combined screening for Down syndrome at 11 to 14 weeks of gestation. Individuals' markers were converted to multiples of the median (MoM) using expected medians estimated by performing a weighted regression analysis. Multivariate regression analysis was performed to assess the influence of maternal weight, parity, ethnicity, chorionicity in twin pregnancies, smoking, insulin-dependent diabetes and mode of conception on individual marker MoM levels. Both free beta-hCG and PAPP-A median values demonstrated an exponential relationship with gestational age in days. Multivariate regression analysis indicated that free beta-hCG MoM was statistically significantly dependent on maternal weight (P < 0.0001) and chorionicity in twin pregnancy (both monochorionic and dichorionic P < 0.0001), that PAPP-A MoM was dependent on maternal weight (P < 0.0001), parity (P < 0.0001), chorionicity in twin pregnancy (both monochorionic and dichorionic P < 0.0001) and mode of conception (P = 0.002), and that fetal NT-MoM was dependent on maternal weight (P = 0.0006) and mode of conception (P = 0.012). Normative values have been generated to allow conversion of NT, free beta-hCG and PAPP-A to their MoM equivalents and correction factors have been determined to adjust for maternal and pregnancy characteristics for use in ethnic Chinese women undergoing first-trimester screening for aneuploidy.

Determining chorionicity in twin gestations: three‐dimensional (3D) multiplanar sonographic measurement of intra‐amniotic membrane thickness

Measuring the thickness of the membranes to determine chorionicity in twins using two-dimensional (2D) ultrasound may provide uncertain results, given the possibility of measuring in an oblique view. We aimed to determine whether chorionicity can be assessed during the second and third trimesters by measuring the thickness of the membranes with three-dimensional (3D) multiplanar ultrasound, which ensures the measurement is perpendicular to the membranes, and to evaluate the reproducibility of the technique. This was a prospective study of 84 twin pregnancies (30 monochorionic and 54 dichorionic) between 20 and 35 weeks of gestation. The dividing membranes between the fetuses were visualized with 2D and 3D transabdominal sonography and the thickness of the membranes was measured by the multiplanar technique. Intraobserver variability was assessed by comparing the measurements obtained in sagittal and axial views by the same observer. We examined the frequency distributions to determine the optimal cut-off point of the thickness of the membranes to predict chorionicity. Kappa index, intraclass correlation coefficients and 95% limits of agreement were calculated to evaluate the inter- and intraoperator variability. We also compared membrane-thickness measurement, during the second and third trimesters, using 2D and 3D ultrasound. In monochorionic and dichorionic pregnancies, respectively, the mean thickness was 1.42 (SD, 0.31) mm and 2.48 (SD, 0.47) mm. With 3D ultrasound, the intraclass correlation coefficient was 0.99 in all cases. The 95% limits of agreement were all within +/-0.2 mm. The best cut-off for membrane thickness for discriminating monochorionic from dichorionic twinning was 1.8 mm. Using this cut-off, there were one false-negative (sensitivity, 97%; 95% CI, 83-99%) and three false-positive (specificity, 94%; 95% CI, 85-99%) diagnoses of monochorionic twins. Kappa indices for intra- and interoperator variability were all above 90%, suggesting almost perfect agreement. Measurements with 2D sonography were less accurate (sensitivity and specificity, 83%). Prenatal assessment of dividing membranes using 3D multiplanar ultrasound is reproducible and may be a useful alternative method for determining chorionicity in twin pregnancies during the second and third trimesters.

Chorionicity determination in twin pregnancies: how accurate are we?

To determine the accuracy of antenatal prediction of chorionicity in twin pregnancies in our institution. Antenatal chorionicity was determined using the number of placental masses, the presence or absence of a twin peak sign and the fetal sex. The gestational age at assessment was documented. Postnatal diagnosis of chorionicity was determined by neonatal sex and placental pathology. Chorionicity was correctly determined in 95% of cases (n = 131); 91% of the monochorionic and 96% of the dichorionic pregnancies were correctly determined. If chorionicity was assessed prior to 14 weeks' gestation (n = 96) the correct diagnosis was made in all except one case. Ultrasound assessment of chorionicity has a high sensitivity and specificity. This is further improved if the assessment is performed prior to 14 weeks' gestation.

Prediction of chorionicity in twin pregnancies at 10-14 weeks of gestation.

To examine the accuracy of sonographic determination of chorionicity in twin pregnancies at 10-14 weeks of gestation. Prospective study on the sonographic prediction of chorionicity at 10-14 weeks of gestation. During a 30 month period, from October 1997 to May 2000, 165 women attending the departments of fetal medicine or ultrasound. Sonographic criteria used in the diagnosis of chorionicity were the number of placental sites, the lambda (lambda) and T signs and the thickness of the inter-twin membrane. The diagnosis of chorionicity was made at the time of the ultrasound examination using all these features and subsequently compared with the postnatal diagnosis, confirmed either by placental histology or discordancy in infant sex. In 150 cases with confirmation of chorionicity following delivery, 116 were postnatally classified as dichorionic and 34 monochorionic. Prenatal ultrasound examination correctly identified chorionicity in 149 (99.3%) cases. The most reliable indicator for dichorionicity was a combination using the lambda sign or two separate placentae with a sensitivity and specificity of 97.4% and 100%, respectively. The most useful test in predicting monochorionicity was the T sign with a sensitivity of 100% and specificity of 98.2%. Measurement of the inter-twin membrane thickness was a less reliable indicator where the sensitivity for dichorionicity and specificity for monochorionicity was only 92.6%. Ultrasound examination of twin pregnancies at 10-14 weeks of gestation predicts chorionicity with a high degree of accuracy using a combination of the number of placentae, lambda and T signs and inter-twin membrane thickness. All hospitals should encourage departments providing ultrasound services to undertake chorionicity determination when examining women with twin pregnancies at this gestation.

Prediction of chorionicity in twin pregnancies at 10–14 weeks of gestation

Prediction of chorionicity in twin pregnancies at 10–14 weeks of gestation

Ultrasound Determination of Chorionicity in Twin Pregnancy: Accuracy and Operator Experience

AbstractTo evaluate the accuracy of ultrasound in early detection of chorionicity and amnionicity in twin pregnancies and evaluate the role of operator-experience, a prospective follow up of 87 consecutive twin pregnancies was performed. Chorionicity and amnionicity were determined by 17 different observers, divided in 2 groups on the basis of their experience, using a composite of US markers at the first US examination confirming a viable intrauterine twin pregnancy. Accuracy of prediction was determined for both groups by comparison with postnatal pathology. From the 87 pregnancies examined at 10.1 (minimum 5.5 weeks, maximum 26.0) weeks of gestation, pathology was available in 82 cases and a correct prediction of chorionicity was made in all but two cases, both being diagnosed as monochorionic while dichorionic by observers belonging the more experienced group. No monochorionic pregnancy was missed and amnionicity was correctly diagnosed in all cases, including two monoamniotic twins. We conclude that use of a composite of ultrasound markers for early detection of chorionicity and amnionicity is reliable in a clinical setting where physicians with a variable degree of experience perform ultrasound examination.