Genetic amniocentesis in women 20-34 years old: associated risks.

The aim of this retrospective controlled study is to evaluate the impact of predisposing factors on amniocentesis-related fetal loss. It comprises 3910 consecutive cases of women, aged 20-34 years, who had genetic amniocentesis during the years 1992-97 (study group). The control group comprised 5324 women under 35, at low risk for Down syndrome, during the same period. The fetal losses in both groups were analysed, in respect of: (a) maternal historical conditions; and/or (b) bleeding during current pregnancy. The leading indication for amniocentesis in women 20-34 years was maternal anxiety, mainly for marginal age (33-34 years), which accounted for a remarkable 34.4% of the study group. Total fetal loss rate up to the 28th week was 2.1% in the study group versus 1. 5% in controls. A history of previous spontaneous or induced abortions, as well as bleeding during the current pregnancy, was associated with a substantial rise of fetal loss in both groups. In cases with no predisposing factors, the added fetal loss rate was 0.03%. Previous abortions and bleeding during the current pregnancy are associated with the most fetal losses after amniocentesis. In the absence of these, the added fetal loss rate (0.03%) is non-significant.