Pregnancy outcome after fetal reduction in women with a dichorionic twin pregnancy
L van de Mheen1, S M P Everwijn2, M F C M Knapen3
1Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands lidewijvandemheen@gmail.com.
Study Question:
What are the pregnancy outcomes for women with a twin pregnancy that is reduced to a singleton pregnancy?
Summary Answer:
Fetal reduction of a twin pregnancy significantly improves gestational age at birth and neonatal birthweight, however at an increased risk of pregnancy loss and preterm delivery.
What Is Known Already:
Women with a multiple pregnancy are at increased risk for preterm delivery. Fetal reduction can be considered in these women.
Study Design, Size, And Duration:
Retrospective cohort study of 118 women with a twin pregnancy reduced to a singleton pregnancy between 2000 and 2010.
Participants/Materials, Setting, And Methods:
We compared the outcome of pregnancy in consecutive women with a dichorionic twin pregnancy that was reduced to a singleton pregnancy to that of women with a dichorionic twin pregnancy that was managed expectantly and women with a primary singleton pregnancy. Reductions were performed between 10-23(6/7) weeks' gestation by intracardiac or intrathoracic injection of potassium chloride, mostly for congenital anomalies. We compared median gestational age, pregnancy loss <24 weeks, preterm delivery <32 weeks, neonatal birthweight and perinatal deaths.
Main Results And The Role Of Chance:
We studied 118 women with a twin pregnancy that was reduced to a singleton, 818 women with an ongoing dichorionic twin pregnancy and 611 women with a primary singleton pregnancy. Loss of the entire pregnancy <24 weeks and preterm delivery occurred significantly more in the reduction group compared with the ongoing twin group (11.9 versus 3.1% <24 weeks, P< 0.001 and 18.6 versus 11.5% <32 weeks, respectively, P < 0.001). In the reduction group, the percentage of women without any surviving child was significantly higher compared with the ongoing twin and primary singleton group (14.4, 3.4 and 0.7%, respectively, P < 0.001). Median gestational age was 38.9 weeks (interquartile range (IQR) 34.7-40.3) for reduced pregnancies, 37.1 weeks (IQR 35.3-38.1) for ongoing twin pregnancies and 40.1 (IQR 39.1-40.9) for primary singletons (P < 0.001 for all comparisons).
Limitations, Reasons For Caution:
The main limitations of the study were its retrospective character, and the fact that indications for reduction were heterogeneous.
Wider Implications Of The Findings:
In women with a dichorionic twin pregnancy fetal reduction increases median gestational age only at considerable risk of complete early pregnancy loss.
Study Funding/Competing Interests:
The study was not funded. None of the authors has conflicts of interest.
