Selective Reduction of Multiple Pregnancies Into Singleton Pregnancy: Treatment Analysis for Fetal Position
Haiyan Liu1,2, Run Chen1,2, Xuan Huang1,2
1Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China, sysu.edu.cn.
Journal of Pregnancy
|June 24, 2026
Summary
Selective reduction of the monochorionic-diamniotic (MCDA) twin in dichorionic triamniotic (DCTA) pregnancies, when located superiorly, significantly lowers miscarriage rates and improves gestational age at delivery.
Area of Science:
- Reproductive Medicine
- Maternal-Fetal Medicine
- High-Risk Obstetrics
Background:
- Assisted reproductive technology has increased high-risk triplet pregnancies, particularly dichorionic triamniotic (DCTA) triplets.
- Monochorionic-diamniotic (MCDA) twins within DCTA pregnancies share a placenta, increasing risks like twin-to-twin transfusion syndrome.
- Selective reduction to a singleton via multifetal pregnancy reduction (MFPR) improves outcomes, but fetal location's impact is unclear.
Purpose of the Study:
- To compare obstetric outcomes in DCTA triplet pregnancies undergoing MFPR based on the reduced MCDA twin pair's position.
- To investigate if superior (farther from cervix) versus inferior (closer to cervix) positioning of the reduced MCDA twin impacts pregnancy success.
Main Methods:
- Retrospective analysis of 200 DCTA triplet pregnancies undergoing MFPR to a singleton.
- Patients categorized into Group A (superior MCDA pair) and Group B (inferior MCDA pair).
- Primary outcomes: miscarriage rate before 24 weeks and gestational age at delivery.
Main Results:
- Group A (superior) had significantly lower miscarriage rates (4.1% vs. 17.9%) and higher gestational age at delivery (38.38 vs. 37.36 weeks) compared to Group B (inferior).
- Low birth weight incidence was significantly lower in Group A (10.3% vs. 26.6%).
- No significant differences in perinatal death or Apgar scores between groups.
Conclusions:
- In DCTA triplet pregnancies, the location of the reduced MCDA twin is a critical factor for pregnancy success.
- Selective reduction of a superiorly located MCDA twin is associated with improved obstetric outcomes, including reduced miscarriage and higher gestational age.
