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

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

Study Design: 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.

Results: 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.

Conclusions: 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.