Pregnancy Outcome After Fetal Reduction in Women With a Dichorionic Twin Pregnancy

Women with dichorionic twin pregnancies can be faced with difficult decisions in the setting of 1 abnormal fetus, caused by hereditary disease, or a chromosomal or structural abnormality. Selective feticide is sometimes presented as an option for these women. This technique has been shown to allow a pregnancy to progress and result in the birth of at least 1 healthy fetus. In this retrospective, multicenter (10 perinatal centers) cohort study that spanned 10 years (2000–2010), the authors examined records of 118 women with dichorionic twin reduced to singleton pregnancy (study group) and compared their pregnancy outcomes to those of women with either ongoing dichorionic twin pregnancy (611 women) or primary singleton pregnancy (818 women). The authors hoped to assess the course of pregnancy for women in the study group and evaluate suitability of fetal reduction, especially if performed for the purpose of improving outcome. In this study, fetal reduction was completed via transabdominal, intracardiac, or intrathoracic injection of potassium chloride between 100/7 and 236/7 weeks’ gestation. Outcomes examined were gestational age at delivery, delivery at less than 24 weeks, delivery at less than 32 weeks, neonatal birth weight, and perinatal death. Results show that after reduction 11.9% of the study group lost their entire pregnancy prior to 24 weeks’ gestation, compared with 3.1% of women with ongoing dichorionic pregnancy and 0.7% of women with singleton pregnancy (P < 0.001); 18.6% of women in the study group also delivered before 32 weeks’ gestation, compared with 11.5% women with ongoing twin pregnancy and 1% women with singleton pregnancy (P < 0.001). Median neonatal birth weight was 3125 g, compared with 2578 g in ongoing twin pregnancy and 3450 in primary single pregnancy (P = 0.001). In terms of perinatal death, 85.6% of intended fetuses survived in the study group, compared with 94% to 99.3% in the control groups. Another way to view this result is that 14.4% of women in the study group were without any surviving child, versus 3.4% in the ongoing twin pregnancy and 0.7% in the singleton group (P < 0.001). Overall, fetal reduction resulted in a significant 2-week prolongation of pregnancy (38.9 vs 37.1 weeks), but not to the level of a primary singleton pregnancy (40.1 weeks). In addition, women with dichorionic twin pregnancy who underwent fetal reduction had a higher chance of delivering prematurely than did those with ongoing twin pregnancy, without any lowered risk of perinatal mortality. The authors thus do not advise fetal reduction of a dichorionic twin pregnancy to improve obstetric outcome.