Miscarriage risk from amniocentesis performed for abnormal maternal serum screening

The purpose of this study was to evaluate miscarriage after mid-trimester amniocentesis for abnormal maternal serum screening.

An analysis of summary data from the California State maternal serum screening program on 32,050 women with an abnormal serum screen, a singleton fetus, and normal ultrasound was performed. Miscarriage before 24 weeks, days until miscarriage, gestational age at miscarriage, and maternal factors were compared. The power of this study could detect a 50% increase in miscarriage.

The miscarriage rate with amniocentesis, 0.46% (69/15,005), was no different than without, 0.53% (90/17,045), P = .38. There was no difference in maternal age, serum biochemical factors, gestational age at miscarriage (21.1 weeks for both groups), or days until miscarriage (23 after amniocentesis and 20.4 without). Log-rank test revealed no difference for gestational age at miscarriage (P = .61) or number of days until miscarriage (P = .40).

The rate and timing of miscarriage was similar with or without amniocentesis in California women with abnormal maternal serum screening.