Genetic amniocentesis in multiple pregnancy

Second-trimester genetic amniocentesis is the most frequently used invasive prenatal diagnostic technique. Several reports have been published about the effect of genetic amniocentesis on fetal loss in multiple pregnancies over the past two decades. Here we analyze our experience with genetic amniocentesis in multiple pregnancies over the past 10 years.

Details of 184 multiple pregnancies were processed in all cases in whom genetic amniocentesis was performed in women who presented at our department since 1990. The outcomes of 175 cases (95.1%) out of 184 genetic amniocenteses were available to us. As a control group, we followed up the outcome of 300 twin pregnancies in which no genetic amniocenteses were performed.

We found that the proportion of spontaneous losses in multiple pregnancies between the 18th and the 24th gestational weeks was 2.39%, whereas if genetic amniocentesis was performed the loss rate before the 24th week was 3.87%. The perinatal mortality rate was 10.03/1,000 in the group who underwent amniocentesis, while it was 10.52/1,000 in the group without amniocentesis.

Our results suggest that the genetic amniocentesis performed in multiple pregnancies slightly increased (1.48%) the fetal loss rate until the 24th week. Beyond 5 weeks after the procedure, no consequent fetal loss should be expected. In our study the intervention did not have any undesired effect on perinatal mortality rates.