Significance of placental cord insertion site in twin pregnancy.

35: Placental cord insertion and birthweight discordance in twin pregnancies: results of the national prospective EsPRIT trial

Placental pathology in twin to twin transfusion syndrome twins after fetoscopic laser photocoagulation

It is not currently well known to what extent the sites of cord insertion influence the risk of complicated outcome in monochorionic twin pregnancy. The objectives of this study were to examine whether the sites of cord insertion, as determined on prenatal ultrasound examination, affect the risks of adverse outcome, twin-to-twin transfusion syndrome (TTTS) and discordant growth, and whether discordance in insertion sites or velamentous insertion in one or both twins best predicts risk. This was a retrospective cohort study of monochorionic diamniotic twin pregnancies followed from the first trimester. The cohort was divided into three groups of increasing discordance in cord insertion sites: concordant (normal-normal; marginal-marginal; velamentous-velamentous), intermediate (normal-marginal; marginal-velamentous) and discordant (normal-velamentous). Adverse outcome was defined as fetal or neonatal loss or birth prior to 32 weeks. The associations of adverse outcome, TTTS and discordant growth were assessed using logistic regression analysis with the following predictors: the three groups of insertion sites and velamentous insertion in one or both twins. Included in the analysis were 518 pregnancies. On univariate analysis, both discordant and velamentous insertions in one twin increased the risk of adverse outcome, TTTS and discordant growth. Intermediate insertion only increased the risk of discordant growth. Velamentous insertion in both twins increased the risk of adverse outcome and TTTS, but not of discordant growth. Multivariate logistic regression analysis showed velamentous insertion in one or both twins to independently predict adverse outcome and TTTS. For discordant growth, both intermediate/discordant and velamentous cord insertion in one twin were independent predictors. Velamentous cord insertion in one or both twins increases the risk of adverse outcome and TTTS, irrespective of discordance in the insertion sites, whereas the risk of discordant growth is determined by both discordance in insertion sites and velamentous cord insertion in one twin. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Color Doppler and gray scale sonography can be used prenatally to identify the location of the cord insertion into the placenta. The purposes of this paper were to (1) relate sonographic identification of placental cord insertion with placental pathology; (2) evaluate the possibility that a marginal cord insertion may evolve into a velamentous cord insertion; and (3) determine the frequency and factors affecting sonographic visualization of cord insertion. Our results show that the sonographic assessment of cord insertion correlated with the pathologic outcome in 83% (106 of 128) of singleton pregnancies and at least one of the fetuses in 72% (8 of 11) of twin or triplet pregnancies. Although the sensitivity for identification of an abnormal cord insertion was low (42%), the specificity was high (95%). Our data suggest that marginal cord insertion evolved into velamentous cord insertion in one singleton and one twin. Our results showed that cord insertion was visualized in 54% of fetuses scanned in a routine clinical practice. Cord insertion visualization was possible at all gestational ages, although it was more difficult at later gestational ages. In conclusion, this study provides evidence that (1) ultrasonography (either gray scale or color Doppler) is useful in identifying normal, marginal, and velamentous cord insertion; (2) marginal cord insertion may evolve into velamentous cord insertion as pregnancy progresses; (3) in clinical practice the cord insertion site was visualized in just over half of the cases, and (4) prenatal identification of marginal and velamentous cord insertion potentially may be useful for planning obstetrical management.

To investigate the relationship between abnormal umbilical cord insertion and birthweight discordance in monochorionic diamnionic (MCDA) twins. A total of 137 pairs of MCDAs were retrospectively analyzed who delivered and survived in Hangzhou Women’s Hospital from January 2016 to December 2021. According to different insertion methods, they were divided into normal cord insertion group (n = 57), marginal cord insertion (MCI) group (n = 34) and velamentous cord insertion (VCI) group (n = 46). The correlation was analyzed between different insertion methods of umbilical cord and the discordant birth weight of MCDAs. The gestational age of delivery with velamentous cord insertion was significantly earlier than those with normal and marginal insertion (P < .05). There were significant differences in birthweight between large fetus (F1) and small fetus (F2) with different umbilical insertion methods (P < .05). The birthweight of F1 and F2 in normal insertion group was significantly higher than those in MCI and VCI group (P < .05). Logistic regression analysis showed that VCI was significantly associated with birth weight in F1/F2, birthweight discordance ≥ 20%, and birthweight discordance ≥ 25%, however MCI and VCI were not an independent factor for discordance in birthweight of MCDAs (P > .05). Umbilical cord insertion method can lead to inconsistency in birthweight of MCDA twins, however they were not an independent factor for discordance in birthweight.

IntroductionTwin–twin transfusion syndrome (TTTS) complicates approximately 10%–15% of all monochorionic twin pregnancies. The aim of this review was to evaluate the placental architectural characteristics within TTTS twins following laser and elucidate their impact on fetal outcomes and operative success.Material and MethodsFive databases were searched from inception to August 2023. Studies detailing post‐delivery placental analysis within TTTS twins post‐laser were included. Studies were categorized into two main groups: (1) residual anastomoses following laser and (2) abnormal cord insertion: either velamentous and/or marginal or proximate. The primary outcome was to determine the proportion of TTTS placentas with residual anastomoses and abnormal cord insertions post‐laser. Secondary outcomes included assessing residual anastomoses on post‐laser fetal outcomes and assessing the relationship between abnormal cord insertion and TTTS development. Study bias was critiqued using the Joanna Briggs Institute checklists and Cochrane risk of bias tool. Random‐effects meta‐analysis was used, and results were reported as pooled proportions or odds ratio (OR) with 95% confidence interval (CI). PROSPERO registration: CRD42023476875.ResultsTwenty‐six studies, comprising 4013 monochorionic twins, were included for analysis. The proportion of TTTS placentas with residual anastomoses following laser was 24% (95% CI, 0.12–0.41), with a mean and standard deviation of 4.03 ± 2.95 anastomoses per placenta. Post‐laser residual anastomoses were significantly associated with intrauterine fetal death (OR, 2.38 [95% CI, 1.33–4.26]), neonatal death (OR, 3.37 [95% CI, 1.65–6.88]), recurrent TTTS (OR, 24.33 [95% CI, 6.64–89.12]), and twin anemia polycythemia sequence (OR, 13.54 [95% CI, 6.36–28.85]). Combined abnormal cord (velamentous and marginal), velamentous cord, and marginal cord insertions within one or both twins following laser were reported at rates of 49% (95% CI, 0.39–0.59), 27% (95% CI, 0.18–0.38), and 28% (95% CI, 0.21–0.36), respectively. Combined, velamentous and marginal cord insertions were not significantly associated with TTTS twins requiring laser (p = 0.72, p = 0.38, and p = 0.71, respectively) vs non‐TTTS monochorionic twins.ConclusionsTo the best of our knowledge, this is the first review to conjointly explore outcomes of residual anastomoses and abnormal cord insertions within TTTS twins following laser. A large prospective study is necessitated to assess the relationship between abnormal cord insertion and residual anastomoses development post‐laser.

Aims Among the increasing twin gestations, monochorionic twins occur in about 12 to 15% of all twin gestations and the occurrence is about 1 in 20 in assistive reproductive technology pregnancies. Early detection of twin to twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR) aids the obstetrician in counseling and therapy as required. Materials and methods This is a retrospective cohort study of monochorionic diamniotic (MCDA) pregnancies referred from January 2011 to June 2013. Those cases that had crown rump length and nuchal translucency measurements done in the first trimester and then at least one subsequent scan at &gt; 16 weeks, at the institution were chosen. The objective was to assess the utility of placental site of cord insertion in early second trimester scan to predict fetal outcome in monochorionic twin pregnancy. The patient characteristics, placental cord insertion site, and neonatal outcomes were compared among TTTS, sIUGR, and normal groups. Discussion Of 89 MCDA pregnancies, only 60 had been referred for second trimester scan. Among these, in 48 (80%) of pregnancies, both babies were delivered and discharged alive and well. Cord insertions that were eccentric or central were classified as “type A”. Marginal and velamentous cord insertions were classified as “type B”. Pregnancies with both types A and B insertions were called “concordant cord insertions group” and the others were classified as “discordant cord insertions” group. The two groups were compared to look for the pregnancy complications — TTTS or sIUGR. Results The concordant cord insertions (n = 33) had 84.8% of pregnancies having a normal pregnancy and 12.1 and 3.1% developing sIUGR and TTTS respectively. The discordant cord insertion group (n = 27) had 59.2% with normal findings at the second scan and 14.8 and 26% developing sIUGR and TTTS respectively. The incidence of TTTS was 30% in twin pairs with discordant cord insertions and 3% in twin pairs with concordant cord insertions (p = 0.0158). Cord insertions did not influence the occurrence of sIUGR in our study. (p = 0.69). Significantly more pregnancies with concordant cord insertions had normal outcomes (p = 0.02). Conclusion Determination of placental site of cord insertion should be incorporated into protocols of twin pregnancy care. This is a window of opportunity to gain valuable information regarding the pregnancy. Further large studies incorporating fetal biometric and Doppler parameters could show the relative utility of each parameter in the detection of MCDA vascular complications. If the MCDA pregnancy can be classified as “low risk” then reassessment intervals can be extended. This would help to reduce patient stress and costs involved in repeated scans. How to cite this article Andrew C, Suresh I, Seshadri S. Relationship of Fetal Complications in Monochorionic Diamniotic Twin Pregnancy with Placental Site Cord Insertion: A Retrospective Analysis of 30 Months Data in a Referral Fetal Medicine Center. J South Asian Feder Obst Gynae 2016;8(4):304-308.

To evaluate the association between antenatal diagnosis of velamentous and marginal placental cord insertions with adverse perinatal outcomes of small-for-gestational-age (SGA) birth weight (less than the 5th percentile), caesarean birth, and perinatal mortality. Using a diagnostic imaging database, we performed a cohort study of all consecutive singleton pregnancies (35,391), including 1,427 cases of marginal and 107 cases of velamentous cord insertion, delivered after 24 6/7 weeks of gestation between January 1, 2012, and December 31, 2015, at a single Canadian tertiary care center. Cases with placenta previa, vasa previa, no documented cord insertion, or fetal anomalies were excluded. In the overall cohort, the rate of birth weight less than the 5th percentile was 5.2%, the rate of cesarean delivery was 27.1%, and the rate of perinatal mortality was 0.24%. Velamentous cord insertion was associated with SGA (relative risk [RR] 2.19, 95% CI 1.28-3.74). This persisted after controlling for smoking during pregnancy, diabetes, and hypertension (adjusted odds ratio [aOR] 1.98, 95% CI 1.03-3.84). Velamentous cord insertion was also associated with an increased risk of caesarean birth (RR=1.38, 95% CI=1.08-1,77) and perinatal death (1.87%, RR 8.15, 95% CI 2.02-32.8), a relationship that persisted after controlling for smoking during pregnancy, diabetes, and hypertension (aOR 1.53, 95% CI 1.01-2.32). Marginal cord insertion was not associated with birth weight less than the 5th percentile (RR 1.23, 95% CI 1.00-1.51), cesarean delivery (RR 1.01, 95% CI 0.92-1.10), or perinatal death (RR 1.53, 95% CI 0.62-3.78). Antenatal diagnosis of velamentous placental cord insertion is associated with birth weight less than the 5th percentile.

Guideline No. 440: Management of Monochorionic Twin Pregnancies

To explore the prevalence, number and size of anastomoses, placenta sharing and placental cord insertion in twin-to-twin transfusion syndrome (TTTS). A total of 97 monochorionic placentas were collected from June 2013 to June 2014 during fetoscopic laser surgery or selective feticide. After eliminating 23 placentas of selective intrauterine growth restriction (sIUGR), 79 placents were analyzed. There were 24 placentas of TTTS and 32 placentas of normal monochorionic twins (McT) without complex twin preganancy. Placental sharing, placental cord insertion, angioarchitecture and diameter of vascular anastomosis were assessed by placental injection with colored dye and compared between TTTS and McT without complex twin preganancy. (1) Arterio-arterial (AA) anastomoses were detected in 37.5% of TTTS placentas versus 75.0% in normal McT placentas (P<0.01). (2) The median number of AA anastomoses in TTTS group was significantly less than that in normal group (0.0 vs 1.0, P<0.01). And the median total diameter of AA anastomoses in TTTS group was significantly smaller than that in normal group (0.00 vs 2.25 mm, P<0.01). (3) The incidence of placentas with at least one cord non-central insertion (70.8% vs 62.5%, P>0.05), velamentous insertion (25.0% vs 6.3%, P>0.05) in TTTS and normal McT had no difference respectively. The placental territory discordance (PTD) had no difference between TTTS and normal McT (0.33 vs 0.22, P>0.05). AA anastomosis occurs less frequently in TTTS placentas, supporting the concept of a protective role of AA anastomoses in TTTS. McT placentas without AA anastomosis have high risk for TTTS. The compensatory ablitiy of AA anastomosis may determine the time of TTTS onset. Non-central or velamentous cord insertion, placental sharing discordance are not risk factors for TTTS.

ISUOG Practice Guidelines: role of ultrasound in twin pregnancy.

Abnormal umbilical cord insertion has been associated with unequal sharing of the placental vasculature between twins. A higher prevalence has been reported in pregnancies complicated by selective growth restriction (sFGR), birth weight discordance (BWD). We aimed to investigate the association between cord insertion site and adverse pregnancy outcomes in twin pregnancies. A single-centre cohort study of twin pregnancies that had placental histology. Higher-order multiples, major fetal anomaly, aneuploidy and MCMA pregnancies were excluded. Cord insertion site was categorised into 3 groups: marginal (attachment <2cm to the placental margin), velamentous (attached to the membrane before reaching the placenta with vessels traversing the membranes), normal. Chorionicity, placental weight, number of cord vessels, examination of the membranes, ultrasound findings, maternal characteristics and pregnancy outcome were collected. 546 pregnancies were eligible; 497 (146 monochorionic; 351 dichorionic) were included in the analysis. Significant differences were found between the normal and abnormal cord insertion groups with regards to BWD (P=0.001), BWD>25% (P=0.001), and absolute Z-score differences (P=0.020). Velamentous, but not marginal, cord insertion was significantly associated with sFGR (OR 8.51,95%CI 2.09-34.58;P=0.03) and BWD>25% (OR 11.88,95%CI 3.54-39.79;P=0.04). In MCDA, but not DCDA pregnancies, the rate of composite adverse outcome was higher in those with abnormal cord insertion (70.0% vs 53.0%, p=0.04). Selective fetal growth restriction and birthweight discordance are more common in twin pregnancies with abnormal cord insertion. MCDA twins with velamentous cord insertion are at increased risk of sFGR, and composite adverse pregnancy outcome.

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

Our study aims to evaluate the umbilical vein (UV) hemodynamic change in the prenatal cohort of pregnancies diagnosed with abnormal placental cord insertion (aPCI). From January 2022 to December 2022, the fetal umbilical cord insertion site was sonographically examined in singleton fetuses, and umbilical cord blood flow was calculated. The umbilical artery and UV Doppler flow indexes were assessed in cases of normal and abnormal cord insertion. Among 570 singleton fetuses between 18 + 0 and 40 + 6weeks of gestation in the final study, the umbilical vein blood flow (UVBF) in the 3 groups of normal umbilical cord insertions, marginal umbilical cord insertions, and velamentous umbilical cord insertions was 145.39ml/min, 146.18ml/min, and 93.96ml/min, respectively. UVBF was significantly lower in the velamentous cord insertion (VCI) group than in the other groups (P < 0.05). Compared with the normal cord insertions group, lower birth weight (2820 ± 527g vs. 3144 ± 577g, P < 0.05), delivery at an earlier gestational age (38.0 ± 1.55weeks vs. 38.8 ± 2.34weeks, P < 0.05), higher bicarbonate (25.08 ± 1.72mmol/L vs. 22.66 ± 4.05mmol/L, P < 0.05), and higher standard base excess (-1.14 ± 1.50mmol/L vs. -3.30 ± 3.22mmol/L, P < 0.05) were found in the VCI group. We observed lower UVBF volume with aPCI. Hence, we propose UVBF analysis to evaluate fetal aPCI according to UV hemodynamics as an advisory in prenatal care. This would be useful and improve obstetricians' clinical explanation about the potential prenatal consequences so that parents can opt for future prenatal care during pregnancy.

Prevalence of velamentous and marginal umbilical cord insertions; a comparison of term singleton ART and non-ART pregnancies