Is it worth reducing twins to singletons after IVF-ET? a retrospective cohort study using propensity score matching

Abstract

To explore whether elective fetal reduction from dichorionic twins to singletons after IVF-ET (In vitro fertilization and embryo transfer) is associated with increased take-home baby rate and improved pregnancy outcome. A retrospective cohort study using propensity score matching. We conducted a retrospective cohort study of dichorionic twin pregnancy after IVF-ET between 2009 and 2015. The reduced group included 77 women who underwent transvaginal elective fetal reduction between 7 to 8 weeks of gestation. The non-reduced group (n=3589) comprised patients who were managed expectantly without elective fetal reduction (including patients with later selective fetal reduction due to fetal abnomalities, spontaneous fetal reduction after 7-8 weeks and induced labor due to maternal complications or complex fetal abnomalities). We conducted propensity score matching to control for maternal age, body mass index, infertility types and main causes of infertility. The primary assessment of pregnancy outcomes was take-home baby rate which was defined as taking home at least one live baby. Other measurements included the rates of adverse pregnancy outcome, early and late miscarriage, premature delivery as well as gestational age, birth weight and neonatal defects. After propensity score matching, 71 pairs (781 cases, 1:10 matched) were selected for further analyses. The take-home baby rates in the reduced group was significantly lower than in the control group (83.1% vs. 90.7%, OR0.50, 95%CI 0.27 to 1.03, P=0.042). The adverse outcome rate in the two groups were 19.7% vs. 13.5%, P=0.152. The miscarriage rate seems to be higher in the reduced group, but did not reach statistical significance (early miscarriage, 5.6% vs. 2.8%; late miscarriage, 7.0% vs. 5.6%; total, 12.7% vs. 8.5%). Premature delivery rate was lower in reduced group (12.7% vs. 46.3%, OR 0.17, 95%CI 0.08-0.33, P<0.001). Over 90% of premature deliveries in non-reduced group were over 32 weeks while the proportions were equal in reduced group. The median delivery age was 38 weeks and 36 weeks in reduced and non-reduced group (P<0.001). Birth weight was significantly higher in reduced group, with a median of 3.0Kg vs. 2.5Kg (P<0.001). Dichorionic twin pregnancies after IVF-ET with elective fetal reduction were at lower risk of premature delivery after 32 weeks of gestation, but the chance of taking home at least one live baby was significantly decreased.Tabled 1Comparisons of Pregnancy outcomes BEFORE and AFTER matchingVariablesBefore matching (N=3660)After matching (N=781)P valueReduced group (n=71)Non-reduced group (n=3589)Reduced group (n=71)Non-reduced group (n=710)>0.05Early miscarriage(<12w)4 (5.63%)109 (3.04%)4 (5.63%)20 (2.8%)>0.05Late miscarriage (>12w)5 (7.04%)160 (4.46%)5 (7.04%)40 (5.6%)>0.05Total miscarriage9 (12.67%)269 (7.50%)9 (12.67%)60 (8.5%)>0.05Preterm delivery <32 w5 (7.04%)142 (3.96%)5 (7.04%)30 (4.2%)>0.05Preterm delivery >32 w4 (5.63%)1557 (43.4%)4 (5.63%)299 (42.1%)0.00Total preterm delivery9 (12.67%)1699 (47.3%)9 (12.67%)329 (46.3%)0.00Term delivery53 (74.6%)1670 (46.5%)53 (74.6%)319 (44.9%)0.00Live Birth62 (87.3%)3369 (93.9%)62 (87.3%)648 (91.3%)>0.05Take home baby59 (83.1%)3361 (93.6%)59 (83.1%)644 (90.7%)0.04Adverse outcome14 (19.7%)449 (12.5%)14 (19.7%)95 (13.5%)>0.05 Open table in a new tab