Does the timing of fetal reduction from dichorionic twin pregnancies to singleton pregnancies influence premature birth risk? A retrospective cohort study.

capsuleThe gestational age at fetal reduction had no effect on pregnancy outcome when reduction was performed before 17 + 4 weeks. After 17 + 4 weeks, the later the fetal reduction was done, the earlier the delivery and lower the birthweight.

objectiveTo investigate the impact of gestational age at fetal reduction on pregnancy outcomes and identify the optimal reduction timing associated with the lowest advanced pregnancy outcome risk of dichorionic twins that were reduced to singleton.

backgroundPrevious studies have indicated gestational age at fetal reduction of twin pregnancies might be associated with risk of adverse pregnancy outcome. However, existing literature on this topic has been inconsistent. As fetal reduction in twin pregnancies is increasingly practiced, these data are important for clinicians when counseling couples about fetal reduction. STUDY

designA retrospective cohort study was conducted on dichorionic twin pregnancies that underwent fetal reduction to singletons at a single reproductive center between July 2005 and July 2021.

methodsSmooth curve fitting and a segmented regression model were utilized to analyze the threshold effect between the gestational age at fetal reduction and pregnancy outcomes, including pregnancy loss, gestational age at birth and birthweight. Then the study population was divided into two groups according to inflection point of gestational age at fetal reduction as early-reduction group and late-reduction group. The primary pregnancy outcomes compared between groups included the rates of pregnancy complications, pregnancy loss, preterm birth and low birthweight.

resultsIn total, 463 dichorionic twin pregnancies were included in the study. No significant correlation was found between pregnancy loss risk before 24 weeks and gestational age at reduction (P = 0.428). The gestational age at birth and birthweight shown a nonlinear change with increasing gestational age at reduction. When reduction was performed before 17

conclusionsFetal reduction of dichorionic twin pregnancies performed after 17 + 4 weeks increases risk of preterm birth and LBW, highlighting the need for enhanced monitoring and management of premature related risks. Fetal reduction before 17 + 4 weeks is a preferable option for dichorionic twin pregnancies as it reduces the risk of prematurity without increasing the risk of pregnancy loss. These findings provide new information for counseling couples with dichorionic (DC) twins about fetal reduction.