To explore the effects of different approaches for second-trimester multifetal pregnancy reduction on pregnancy outcome in women with dichorionic triamniotic (DCTA) triplet.

A retrospective study was performed on 51 women with DCTA triplet pregnancies who were referred to Guangdong Women and Children Hospital for second-trimester multifetal pregnancy reduction from January 2014 to January 2020. All participants were divided into either preventive group (n=39) or treatment group (n=12) according to the indication for multifetal pregnancy reduction, and they were further allocated to three subgroups based on different reduction methods, which were reduction to dichorionic twin by radiofrequency ablation (RFA) (RFA subgroup), reduction to monochorionic singleton (KCl-singleton subgroup) or monochorionic twin (KCl-twin subgroup) by cardiac injection of potassium chloride. Pregnancy loss rate, neonatal birth weight, gestational age at delivery, incidence of intrauterine death, and neonatal death were compared and analyzed between different groups using t-test, analysis of variance, Chi-square test, Fisher's exact test and Bonferroni correction.

(1) The mean gestational week at operation in the treatment group was significantly later than that in the preventive group [(18.5±3.1) vs (15.0±2.3) weeks, t=-4.209, P<0.001]. In the preventive group, the mean gestational week at operation in the RFA subgroup was later than the KCl-singleton and KCl-twin subgroup[(17.2±1.6) vs (13.8±1.5) and (12.7±1.0) weeks,t=6.630 and 3.875, respectively, both P<0.05]. (2) The postoperative pregnancy loss rate in the preventive group was decreased compared with the treatment group [10.3%(4/39) vs 5/12, Fisher's exact test,P<0.05], and the live birth ratio was increased [ 85.7%(48/56) vs 10/18,χ²=5.640, P=0.018]. No live birth infants with birth weight <1 500 g was reported in the KCl-singleton subgroup in preventive group, and the statistical significance was observed in the intra-group differences ( P<0.05) rather than the pairwise comparison differences in the preventive group. For the proportion of live births, there was a statistically significant difference in the intra-group comparison in the treatment group, which was higher in the RFA subgroup than that in the KCl-twin subgroup (6/6 vs 1/6,P=0.045). No significant difference was revealed among pregnancy loss rate, gestational weeks at delivery, the mean birth weight, premature delivery <32 gestational weeks, and full-term birth rate among three different approaches within the two groups. (3) No monochorionic twin complications or perinatal death occurred in any RFA or KCl-singleton subgroups in the two groups. In the KCl-twin subgroups including five cases with ten fetuses, including three live birth, four miscarriage, three intrauterine death occured, while no neonatal death was reported. One case with selective fetal uterine growth restriction in the preventive group delivered two live births, and one case with twin-to-twin transfusion syndrome in the treatment group had intrauterine death in one fetus and one survival neonate.

The pregnancy outcome of multifetal pregnancy reduction to dichorionic diamniotic twins by RFA or reduction to singleton by cardiac injection of potassium chloride are comparative in women with DCTA triplet, regardless of whether it is a preventive or therapeutic reduction.

Pregnancy, triplet; Pregnancy reduction, multifetal; Radiofrequency ablation; Potassium chloride; Injections; Pregnancy outcome