Impact of Marginal and Velamentous Cord Insertion on Uterine Artery Doppler Indices, Fetal Growth, and Preeclampsia

Association between placental location and cord insertion site with pre-eclampsia: a retrospective cohort study

OBJECTIVE

The relationship between placental location in pregnancies without previa and adverse pregnancy outcomes has not been well studied. Additionally, the impact of abnormal cord insertion sites remains controversial. Therefore, the objective of this study was to explore the adverse outcomes associated with placental location and abnormal cord insertion in nulliparous women and to assess their impact on pregnancy outcomes.

METHODS

This retrospective cohort study was conducted at a single tertiary hospital between January 2019 and June 2022. The study included nulliparous women with singleton pregnancies who delivered live infants and had available data on placental location and umbilical cord insertion site from a second- or third-trimester ultrasound. Placental location was categorized as anterior or posterior using transabdominal ultrasonography. The association between placental location/cord insertion site and pre-eclampsia was evaluated using multivariate logistic regression analysis. We compared the area under the curve to evaluate the impact of placental location and cord insertion site on pre-eclampsia.

RESULTS

A total of 2219 pregnancies were included in the study. Pre-eclampsia occurred significantly more frequently in the anterior group than in the posterior group (8.21% vs. 3.04%, p < .001). In multivariate analysis investigating the association between placental location and pre-eclampsia, anterior placenta and marginal cord insertion showed increased odds ratios for pre-eclampsia of 3.05 (95% confidence interval [CI] 1.68-6.58) and 3.64 (95% CI 1.90-6.97), respectively. Receiver operating characteristic (ROC) curves were constructed to predict pre-eclampsia using independent factors from multivariate analyses. Model I, including maternal age, pre-pregnancy body mass index, in vitro fertilization, chronic hypertension, overt diabetes, kidney disease, and hematologic diseases, achieved an area under the ROC curve of 0.70 (95% CI 0.65-0.75). Adding cord insertion site and placental location to the model (Model II) improved its predictive performance, resulting in an area under the ROC curve of 0.749 (95% CI 0.70-0.79, p = .02).

CONCLUSIONS

Anterior placenta and marginal cord insertion were associated with an increased risk of pre-eclampsia. Further studies on prospective cohorts are necessary to validate these findings.

Prenatal diagnosis of bilobate placenta: incidence, risk factors and impact on pregnancy outcomes

OBJECTIVES

To investigate the incidence and risk factors of bilobate placenta, as well as to assess its impact on preeclampsia (PE), preterm delivery (PTD) and small-for-gestational age (SGA) neonates.

METHODS

A prospective study of singleton pregnancies, undergoing routine anomaly scan at 20+0-23+6 gestational weeks, was conducted, between 2018 and 2022. The impact of prenatally diagnosed bilobate placenta on PE, PTD and SGA was assessed. Multivariate logistic regression models were employed to assess the independent association between bilobate placenta and the main pregnancy outcomes, using specific confounders. Additionally, a risk factor analysis was performed.

RESULTS

The study population included 6,454 pregnancies; the incidence of prenatally diagnosed bilobate placenta was 2.0 % (n=129). Bilobate placenta was associated with PE (aOR: 1.721; 95 % CI: 1.014-2.922), while no statistically significant association was found between this anatomical variation and SGA (aOR: 1.059; 95 % CI: 0.665-1.686) or PTD (aOR: 1.317; 95 % CI: 0.773-2.246). Furthermore, pregnancies with prenatally diagnosed bilobate placenta had an increased prevalence of abnormal cord insertion (marginal or velamentous) (9.8 vs. 27.1 %; p<0.001) and increased mean UtA PI z-score (0.03 vs. 0.23; p=0.039). Conception via ART (aOR: 3.669; 95 % CI: 2.248-5.989), previous history of 1st trimester miscarriage (aOR: 1.814; 95 % CI: 1.218-2.700) and advancing maternal age (aOR: 1.069; 95 % CI: 1.031-1.110) were identified as major risk factors for bilobate placenta.

CONCLUSIONS

Bilobate placenta, excluding cases of co-existing vasa previa, is associated with higher incidence of PE, increased mean UtA PI z-score and higher probability of abnormal cord insertion, but not with increased risk for SGA or PTD. It is more common in pregnancies following ART and in women with a previous 1st trimester miscarriage.

Associations between velamentous or marginal cord insertion and risk of adverse perinatal outcomes in twin pregnancies: a retrospective cohort study

BACKGROUND

Velamentous cord insertion (VCI) and marginal cord insertion (MCI) are well-known risk factors for adverse perinatal outcomes in singleton pregnancies. However, the potential links between VCI or MCI and perinatal outcomes in twin pregnancies have yet to be systematically evaluated. This study aimed to investigate the relationships between VCI or MCI and perinatal outcomes in twin pregnancies.

METHODS

This retrospective single-center cohort study included women with twin pregnancies who gave birth in a tertiary hospital in Southwest, China between January 2017 and December 2022. VCI and MCI were identified by abdominal ultrasound and confirmed after placental delivery. Logistic regression, multinomial logit regression and generalized estimation equation models were used to evaluate the association between VCI or MCI and perinatal outcomes.

RESULTS

A total of 3682 twin pregnancies were included, including 100 (2.7%) pregnancies with VCI and 149 (4.0%) pregnancies with MCI. Compared to pregnancies with normal cord insertion, both monochorionic and dichorionic pregnancies with VCI were associated with an increased risk of preterm delivery 32-34 weeks (aRRR 2.94, 95% CI 1.03-8.39; aRRR 2.55, 95% CI 1.19-5.46, respectively), while pregnancies with MCI were not associated with preterm delivery. VCI was associated with a higher incidence of placental previa (aOR 6.36, 95% CI 1.92-21.04) in monochorionic pregnancies and placental accreta (aOR 1.85, 95% CI 1.06-3.23) in dichorionic pregnancies. MCI was associated with an increased risk of preeclampsia (aOR 3.07, 95% CI 1.49-6.32), intertwin birthweight discordance ≥ 20% (aOR 2.40, 95% CI 1.08-5.60) and selective fetal growth restriction (aOR 2.46, 95% CI 1.08-5.60) in monochorionic pregnancies and small-for-gestational age neonates (aOR 1.97, 95% CI 1.24-3.14) in dichorionic pregnancies.

CONCLUSIONS

VCI was associated with an increased risk of preterm delivery in twin pregnancies irrespective of chorionicity, whereas MCI was associated with an increased preeclampsia risk, significant intertwin birthweight discordance in monochorionic pregnancies and small-for-gestational age neonates in dichorionic pregnancies.

Impact of velamentous cord insertion on perinatal outcomes: a systematic review and meta-analysis

OBJECTIVE

Velamentous cord insertion may be identified prenatally, but the clinical implications of this diagnosis remain controversial. This meta-analysis aimed to quantitatively summarize current data on the association of velamentous cord insertion and adverse perinatal outcomes.

DATA SOURCES

A systematic search was performed in MEDLINE, Scopus, and the Cochrane Library from inception until May 22, 2022 to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Observational studies including singleton pregnancies with velamentous cord insertion, either prenatally or postnatally identified, and comparing them with those with central/eccentric cord insertion were considered eligible.

METHODS

The quality of the studies was assessed with the Newcastle-Ottawa scale and the risk of bias with the Quality In Prognosis Studies (QUIPS) tool. The main outcome was small-for-gestational-age neonates. Heterogeneity of the studies was evaluated using a Q test and an I² index. Analyses were performed using a random-effects model, with outcome data reported as relative risk or mean difference with 95% confidence interval.

RESULTS

In total, 9 cohort and 2 case-control studies, of which 4 had prenatal and 7 had postnatal velamentous cord insertion diagnosis, were included. The overall prevalence of velamentous cord insertion was estimated to be 1.4% among singleton pregnancies. Compared with the central/eccentric cord insertion control group, pregnancies with velamentous cord insertion were at higher risk of several adverse perinatal outcomes, namely small-for-gestational-age neonates (relative risk, 1.93; 95% confidence interval, 1.54-2.41), preeclampsia (relative risk, 1.85; 95% confidence interval, 1.01-3.39), pregnancy-induced hypertension (relative risk, 1.58; 95% confidence interval, 1.46-1.70), stillbirth (relative risk, 4.12; 95% confidence interval, 1.92-8.87), placental abruption (relative risk, 2.94; 95% confidence interval, 1.72-5.03), preterm delivery (relative risk, 2.14; 95% confidence interval, 1.73-2.65), emergency cesarean delivery (relative risk, 2.03; 95% confidence interval, 1.22-3.38), 1-minute Apgar score <7 (relative risk, 1.53; 95% confidence interval, 1.14-2.05), 5-minute Apgar score <7 (relative risk, 1.97; 95% confidence interval, 1.43-2.71), and neonatal intensive care unit admission (relative risk, 1.63; 95% confidence interval, 1.32-2.02). In a subgroup analysis, prenatally diagnosed velamentous cord insertion was associated with small-for-gestational-age neonates (relative risk, 1.66; 95% confidence interval, 1.19-2.32), stillbirth (relative risk, 4.78; 95% confidence interval, 1.42-16.08), and preterm delivery (relative risk, 2.69; 95% confidence interval, 2.01-3.60). In a sensitivity analysis of studies excluding cases with vasa previa, velamentous cord insertion was associated with an increased risk of small-for-gestational-age neonates (relative risk, 2.69; 95% confidence interval, 1.73-4.17), pregnancy-induced hypertension (relative risk, 1.94; 95% confidence interval, 1.24-3.01), and stillbirth (relative risk, 9.42; 95% confidence interval, 3.19-27.76), but not preterm delivery (relative risk, 1.92; 95% confidence interval, 0.82-4.54).

CONCLUSION

Velamentous cord insertion is associated with several adverse perinatal outcomes, including stillbirth, and these associations persist when only prenatally diagnosed cases are considered and when vasa previa cases are excluded. According to these findings, the exact pathophysiology should be further investigated and an effective prenatal monitoring plan should be developed.

Impact of marginal cord insertion on perinatal outcomes: a systematic review and meta-analysis

OBJECTIVE

Despite its high prevalence and the possible link with perinatal complications, marginal cord insertion is surrounded by considerable controversy regarding management. This meta-analysis aimed to study its association with several perinatal outcomes in a manner that provides trustworthy and exact effect measures, enabling us eventually to evaluate its overall risk for pregnancy.

DATA SOURCES

A systematic search was performed in Medline, Scopus, and the Cochrane Library on July 30, 2022, to identify eligible studies.

STUDY ELIGIBILITY CRITERIA

Observational studies, including singleton pregnancies and comparing MCI with central cord insertion or eccentric cord insertion, either prenatally or postnatally identified, were considered eligible.

METHODS

The Newcastle-Ottawa Scale was used to assess study quality, and the Quality in Prognosis Studies tool was used to assess bias risk. The main outcome was small-for-gestational-age neonates. A Q test and an I² score were used to assess study heterogeneity. The analyses were performed using a random-effects model, and the results were expressed as relative risk or mean difference with a 95% confidence interval.

RESULTS

Overall, 15 studies (13 cohort studies and 2 case-control studies) contributed data to the analysis. There was a prenatal diagnosis in 7 studies and a postnatal diagnosis in 8 studies. The overall prevalence of marginal cord insertion was 6.15% (range, 1.13%-11.3%). Pregnancies with marginal cord insertion compared with pregnancies with central cord insertion were found to be at higher risk of small-for-gestational-age neonates (relative risk, 1.25; 95% confidence interval, 1.21-1.29), preeclampsia (relative risk, 1.61; 95% confidence interval, 1.54-1.67), placental abruption (relative risk, 1.53; 95% confidence interval, 1.34-1.75), stillbirth (relative risk, 1.97; 95% confidence interval, 1.02-3.78), preterm delivery (relative risk, 1.47; 95% confidence interval, 1.24-1.75), lower mean gestational age at birth (mean difference, -0.20; 95% confidence interval, -0.38 to -0.01), emergency cesarean delivery (relative risk, 1.39; 95% confidence interval, 1.35-1.44), lower mean birthweight (mean difference, -139.19; 95% confidence interval, -185.78 to -92.61), 5-minute Apgar score of <7 (relative risk, 1.48; 95% confidence interval, 1.00-2.19), and neonatal intensive care unit admission (relative risk, 1.57; 95% confidence interval, 1.20-2.06). When only pregnancies with prenatally diagnosed MCI were considered, the risk remained high regarding small for gestational age (relative risk, 1.34; 95% confidence interval, 1.21-1.48), preeclampsia (relative risk, 1.42; 95% confidence interval, 1.01-1.99), stillbirth (relative risk, 2.99; 95% confidence interval, 1.03-8.70), preterm delivery (relative risk, 1.41; 95% confidence interval, 1.19-1.68), lower mean gestational age at birth (mean difference, -0.22; 95% confidence interval, -0.33 to -0.11), and lower mean birthweight (mean difference, -122.41; 95% confidence interval, -166.10 to -78.73).

CONCLUSION

Here, the higher risk that marginal cord insertion poses for pregnancy, regarding several adverse outcomes, became evident. Many of these associations persisted among the prenatally diagnosed pregnancies. The underlining pathophysiology should be investigated, and further research is needed on the effect of increased surveillance in improving perinatal outcomes.

The Characteristics and Obstetric Outcomes of Type II Vasa Previa: Systematic Review and Meta-Analysis

Vasa previa is a rare fetal life-threatening obstetric disease classified into types I and II. This study aimed to examine the characteristics and obstetric outcomes of type II vasa previa. A systematic review was performed, and 20 studies (1998-2022) were identified. The results from six studies showed that type II vasa previa accounted for 21.3% of vasa previa cases. The characteristics and obstetric outcomes (rate of assisted reproductive technology (ART), antenatal diagnosis, emergent cesarean delivery, maternal transfusion, gestational age at delivery, and neonatal mortality) were compared between type I and II vasa previa, and all outcomes of interest were similar. The association between ART and abnormal placenta (bilobed placenta or succenturiate lobe) was examined in three studies, and the results were as follows: (i) increased rate of succenturiate lobes (ART versus non-ART pregnancy; OR (odds ratio) 6.97, 95% confidence interval (CI) 2.45-19.78); (ii) similar rate of abnormal placenta (cleavage-stage versus blastocyst embryo transfer); (iii) increased rate of abnormal placenta (frozen versus fresh embryo transfer; OR 2.97, 95%CI 1.10-7.96). Although the outcomes of type II vasa previa appear to be similar to those of type I vasa previa, the current evidence is insufficient for a robust conclusion.

Assisted Reproductive Technique and Abnormal Cord Insertion: A Systematic Review and Meta-Analysis

Abnormal cord insertion (ACI) is associated with adverse obstetric outcomes; however, the relationship between ACI and assisted reproductive technology (ART) has not been examined in a meta-analysis. This study examines the association between ACI and ART, and delivery outcomes of women with ACI. A systematic review was conducted, and 16 studies (1990–2021) met the inclusion criteria. In the unadjusted pooled analysis (n = 10), ART was correlated with a higher rate of velamentous cord insertion (VCI) (odds ratio (OR) 2.14, 95% confidence interval (CI) 1.64–2.79), marginal cord insertion (n = 6; OR 1.58, 95%CI 1.26–1.99), and vasa previa (n = 1; OR 10.96, 95%CI 2.94–40.89). Nevertheless, the VCI rate was similar among the different ART types (blastocyst versus cleavage-stage transfer and frozen versus fresh embryo transfer). Regarding the cesarean delivery (CD) rate, women with VCI were more likely to have elective (n = 3; OR 1.13, 95%CI 1.04–1.22) and emergent CD (n = 5; OR 1.93, 95%CI 1.82–2.03). In conclusion, ART may be correlated with an increased prevalence of ACI. However, most studies could not exclude confounding factors; thus, further studies are warranted to characterize ART as a risk factor for ACI. In women with ACI, elective and emergent CD rates are high.