MATERIAL AND METHODS: This is a prospective cohort study including MCDA twins enrolled at the time of first-trimester combined screening. Differences in crown-rump length (CRL), nuchal translucency (NT) thickness, ductus venosus pulsatility index for veins (DV PIV), presence or absence of tricuspid regurgitation and right ventricular E/A ratio were assessed. Receiver operating characteristic (ROC) curves were used to assess the potential value of these measures as predictive tools for identifying a cohort of MCDA pregnancies at high risk of adverse pregnancy outcome.
RESULTS: Sixty-five MCDA pregnancies were included in the analysis. Nine (14%) developed TTTS, 17 (26%) developed sIUGR. The best predictive marker for TTTS was NT discordance of ≥20% (ROC AUC = 0.79; 95% CI 0.59-0.99). Combining measures did not improve performance (AUC = 0.80; 95% CI 0.62-0.99).
CONCLUSION: NT discordance was the most effective characteristic at predicting TTTS but still had a relatively poor positive predictive value (36%). Intertwin differences in CRL, DV PIV and E/A ratio were not predictive of subsequent pregnancy complications. None of these characteristics have sufficient efficacy to be used to triage MCDA twin pregnancies ongoing obstetric surveillance.
MATERIAL AND METHODS: This was a prospective cohort study conducted in a tertiary referral hospital in Sydney, Australia. In all, 212 women with a low-risk pregnancy or with gestational diabetes were recruited including 158 nulliparous and 54 parous women. Maternal demographic, clinical and ultrasound characteristics were collected at 37 weeks of gestation. Semi-Bayesian logistic regression and Markov chain Monte Carlo simulation were used to assess the relation between cervical length and cesarean section in labor.
RESULTS: Rates of cesarean section were 5% (2/55) for cervical length ≤20 mm, 17% (17/101) for cervical length 20-32 mm, and 27% (13/56) for cervical length >32 mm. These rates were 4, 22 and 33%, respectively, in nulliparous women. In the semi-Bayesian analysis, the odds ratio for cesarean section was 6.2 (95% confidence interval 2.2-43) for cervical length 20-32 mm and 10 (95% confidence interval 4.8-74) for cervical length >32 mm compared with the lowest quartile of cervical length, after adjusting for maternal age, parity, height, prepregnancy body mass index, gestational diabetes, induction of labor, neonatal sex and birthweight centile.
CONCLUSIONS: Cervical length at 37 weeks of gestation is associated with intrapartum cesarean section.