The initial report of prospective study for maternal and fetal outcomes to investigate the safety of multifetal pregnancy reduction in Japan.

AIM: This study aimed to establish the safety of multifetal pregnancy reduction (MFPR) and examine its complications, patient background, and psychological impact.

METHODS

This single-center, single-arm, prospective intervention study included 10 women who were treated at our institution between April and December 2024. The indications were triplet or higher-order multiple pregnancies, as well as twin pregnancies with serious maternal complications. Procedures were performed between 11 and 13 gestational weeks, and the patients were observed for up to 1 week postoperatively. The primary outcome was the completion ratio at hospital discharge, whereas the secondary outcomes were the survival rate of non-targeted fetuses, the number of adverse events, and the psychological evaluation of the patients at 1 week postoperatively.

RESULTS

Among the 10 patients, one carried twins, seven carried triplets, and two carried quadruplets; half had received ovulation-induction treatment. The procedure completion rate at discharge was 100%, although one patient required reoperation. The survival rate of non-targeted fetuses was 89.5% (17/19), and adverse events included vaginal bleeding and complete miscarriage. Maternal state-anxiety scores decreased significantly postprocedure, whereas depression scores remained elevated both before and after the procedure.

CONCLUSIONS

The completion rate of MFPR using echo-guided transabdominal potassium chloride infusion was high, ensuring short-term maternal safety. Although no serious adverse event other than one case of total miscarriage was observed, a long-term safety evaluation is warranted. Moreover, the emotional burden on patients is high before and after the procedure, necessitating the importance of long-term support.