The effect of diagnostic amniocentesis and its complications on early spontaneous abortion

The occurrence of early abortion after amniocentesis is a serious problem in the fields of obstetrics and gynecology, and it is always important to discover the factors influencing this phenomenon. The incidence rate has been reported in different studies, even up to about 10%. So far, no studies have been conducted in Iran on the effect of amniocentesis and related complications on early abortion. The aim of this study was to determine the effects of amniocentesis and relevant complications on the incidence of early abortion in pregnant women undergoing amniocentesis.

This cohort study was conducted between March 2014 and March 2016 on pregnant candidates for amniocentesis referred to the perinatology clinic at Ommol-Banin Hospital, Mashhad, Iran. Amniocentesis was performed for all patients with about 20-30cc in the same manner by a perinatologist. Maternal blood group, causes of amniocentesis, amniotic fluid profile (liquid color), status of inserting the needle through the placenta during amniocentesis, amniotic fluid leakage, and bleeding after amniocentesis were considered as exposure factors, and spontaneous abortion after amniocentesis until the end of the 20th week of pregnancy was taken as a consequence. Data were analyzed using IBM-SPSS version 20 via t-test and chi-square. Relative risk (RR) was calculated to determine the causal relationship of exposure with the consequences of spontaneous abortion during the first week after amniocentesis.

This study was performed on 1000 pregnant women with mean age of 33.4±6.0 years (minimum 16, maximum 48 years). The incidence rate of spontaneous abortion after amniocentesis was obtained 1%. There was no association among causes of amniocentesis, maternal blood group, maternal underlying diseases, history of diseases associated with pregnancy, and spontaneous abortion. Based on the chi-square test, a significant statistical relationship was found between amniotic fluid leakage and spontaneous abortion (RR=15.37, p=0.001). There was also a significant statistical relationship between bleeding after amniocentesis and spontaneous abortion; so that in patients with more bleeding, spontaneous abortion was more prevalent (RR=6.83, P=0.001).

According to the results, it seems that amniotic fluid leakage and bleeding after amniocentesis should be considered as two serious complications of amniocentesis, which can cause the incidence of spontaneous abortion in pregnant patients undergoing amniocentesis.