Amniocentesis after multifetal pregnancy reduction: is it safe?

This report reviews the obstetric outcomes of women with multifetal pregnancy reductions who subsequently underwent elective amniocentesis.

Five hundred eight patients underwent multifetal pregnancy reduction at our institution. Among these, 91 patients underwent subsequent elective amniocentesis. The obstetric outcomes of all 508 patients were followed up. By means of logistic regression we evaluated several variables to determine any association with loss rate: (1) the finishing number of fetuses, (2) the number of fetuses undergoing reduction (starting number of fetuses minus the finishing number of fetuses), (3) the gestational age at reduction, (4) the maternal age at reduction, and (5) the procedure protocol. We observed that the finishing number of fetuses, the number of fetuses removed, and the procedure protocol were significantly associated with pregnancy loss rate. Women who underwent subsequent amniocentesis were compared with those who did not undergo amniocentesis. By means of multivariate conditional likelihood analysis we stratified the two groups according to the previously mentioned significant variables to compare the pregnancy loss rates.

Among patients who subsequently underwent elective amniocentesis the total uncorrected pregnancy loss rate was 9.0% and the early premature delivery rate was 4.5%. The number of fetuses removed, the finishing number of fetuses, and the procedure protocol were statistically significantly associated with the loss rate. The adjusted odds ratio relating amniocentesis to the pregnancy loss rate was 0.7 (95% confidence interval, 0.31.5; P =.3.)

The uncorrected rates of pregnancy loss and of early premature delivery among patients with multifetal pregnancy reduction who underwent subsequent amniocentesis were comparable to those of patients with multifetal pregnancy reduction who did not undergo amniocentesis.