Pregnancy and perinatal outcomes of early vs late selective termination in dichorionic twin pregnancy: systematic review and meta‐analysis

Objective: To evaluate outcomes of dichorionic twin pregnancies undergoing early vs late selective termination of pregnancy (ST). Methods: MEDLINE, EMBASE, CINAHL and the Web of Science databases were searched electronically up to March 2022. The primary aim of this study was pregnancy loss prior to 24 weeks. The secondary outcomes included preterm birth (PTB) < 37, 34, and 32 weeks; preterm premature rupture of membranes (pPROM); gestational age (GA) at delivery; cesarean delivery; mean birthweight; Apgar score at 5 minutes < 7; overall neonatal morbidity and neonatal survival. Only prospective and retrospective studies reporting data on the outcome of early (< 18 weeks) versus late (> 18 weeks) ST in dichorionic twin pregnancies were considered suitable for the inclusion. Quality assessment of the included studies was performed using the Newcastle-Ottawa scale for cohort studies. Random-effect head-to-head meta-analyses were used to analyze the data. Results: Seven studies including 646 dichorionic twin pregnancies were included in this systematic review. The risk of pregnancy loss prior to 24 weeks was significantly lower in dichorionic twin pregnancies undergoing early compared to late ST (1% vs 8%, OR 0.25; 95% CI 0.10-0.65, p=0.004). The risk of PTB was significantly lower in dichorionic twin pregnancies undergoing early compared to late ST when considering either PTB < 37 weeks (19% vs 45%, OR 0.36; 95% CI 0.23-0.57, p<0.00001), < 34 weeks (4% vs 19%, OR 0.24; 95% CI 0.11-0.54, p=0.0005) and < 32 weeks (3% vs 20%, OR 0.21; 95% CI 0.05-0.85, p=0.03). The mean birthweight was significantly greater in the early ST group (MD 392.2 grams; 95% CI 59.1-726.7, p=0.02), and the mean GA at delivery showed a trend towards significance (MD 2.47 weeks; 95% CI 0.04-4.91, p=0.05). There was no significant difference between dichorionic twin pregnancies undergoing early compared to late ST in terms of pPROM (p=0.27), Cesarean delivery (p=0.38), Apgar score at 5 minutes < 7 (p=0.35) and neonatal survival of the non-reduced twin (p=0.54). Conclusion: The risk of pregnancy loss prior to 24 weeks, as well as the rate of PTB < 37, 34 and 32 weeks, were significantly higher in dichorionic twin pregnancies undergoing late compared to early ST, thus highlighting the important of early diagnosis of fetal anomalies in twin pregnancies. This article is protected by copyright. All rights reserved.