Second trimester amniocentesis is not a risk factor for very low birth weight and extremely low birth weight.

Objectives. To assess the risk of very low birth weight (VLBW) and extremely low birth weight (ELBW) attributable to second trimester amniocentesis. Methods. Records of 4,877 consecutive amniocentesis, performed between 1997 and 2003, were analyzed. Only VLBW and ELBW in the study population (exposed) and in the control group (unexposed) were evaluated. Comparisons were made between the amniocentesis group versus nonexposed. Odds ratios (OR) and 95\% confidence intervals (95\% CI) were calculated for VLBW and ELBW classes. Results. In the study population, the VLBW were 35 (0.71\%) and the ELBW were 20 (0.41\%). In the control group, the VLBW were 220 (0.67\%) and the ELBW were 112 (0.34\%). The Odds ratios of the VLBW between the study and the control group did not show any statistical significant risk (OR = 1.07, 95\% CI = 0.72-1.54). Also in ELBW odds ratios between study and control group were not statistically significant (OR = 1.20, 95\% CI = 0.7-1.95). Conclusions. No effect of the second trimester amniocentesis was noted on VLBW and ELBW.