Retain singleton or twins? Multifetal pregnancy reduction strategies in triplet pregnancies with monochorionic twins

To assess the effectiveness and feasibility of retaining a singleton or twins for multifetal pregnancy reduction (MFPR) in triplet pregnancy with monochorionic twins.

This retrospective study was conducted from January 2006 to September 2011 at a university reproductive medical center. Multifetal pregnant patients (n=35) with dichorionic triplets underwent MFPR in the first trimester to reduce one or both monochorionic twins. These cases were divided into two groups: Group A (9 MFPR cases to reduce one monochorionic twin) and Group B (26 MFPR for both monochorionic twins). Control A (for Group A) included another 18 cases of trichorionic triplet reduction to twins; Control B (for Group B) included 35 cases of trichorionic triplet reduction to singletons. MFPR was performed during the same period for all groups. Pregnancy outcomes were compared between groups.

Patients were 28-39 years old; the average gestation for fetal reduction was 6-8 weeks. The early abortion rate was lower in Group A than Group B (0 versus 11.5%, p=0.339), but the late abortion rate was significantly higher in Group A. (33.3% versus 0, p=0.000). Groups A and B did not differ significantly in premature labor rate, term birth rate, gestation at delivery and take-home baby rate. The rate of very low and low birth weight was significantly higher in Group A than Group B (50% versus 0, p=0.001), and the average birth weight was significantly lower in Group A (2391.7±318.5 versus 3119.6±523.9, p=0.001). Group A had significantly more low birth-weight newborns than Control A (50% versus 13.3%, p<0.05 [0.024]). Group B (retained singleton) had similar pregnancy outcomes and neonatal conditions as Control B.

Retaining a singleton is always the best choice when deciding about using MFPR to improve pregnancy outcomes. For patients having a triplet pregnancy with monochorionic twins and strongly desiring to keep twins, MFPR in one monochorionic twin was feasible by aspirating embryonic parts early in gestation (6-8 weeks) with no drug injection. Pregnancy outcomes are similar with twin reduction in trichorionic triplet pregnancy.