Effect of Exogenous Progesterone on Fetal Nuchal Translucency: An Observational Study.

Introduction Nuchal translucency is a reliable first trimester screening test for fetal structural and chromosomal defects. Neonates with increased nuchal thickness are at greater risk for anomalies. Exogenous progesterone supplementation may affect nuchal translucency and thus the first trimester anomaly screening. We aimed to study if there was a difference in nuchal thickness between women receiving progesterone in the first trimester compared to those who were not supplemented with progesterone. Material and methods Forty-seven women with documented progesterone intake in the first trimester for at least 10 continuous days before the day of the nuchal translucency scan served as the study group compared to 47 other women who did not receive progesterone. Nuchal translucency was measured between 11 and 13 weeks and six days of gestation. Results The mean nuchal translucency increased with increasing gestation in both groups. Maximum mean nuchal translucency was greatest in the age group 18-20 years (1.35 + 0.1 millimeters) in women receiving progesterone compared to 36-40 years (1.65 + 0.49 millimeters) in controls. The mean nuchal translucency in women receiving progesterone was 1.15 + 0.26 millimeters, and in those that did not receive progesterone, it was 1.23 + 0.35 millimeters (p = 0.314). Conclusions Nuchal translucency increased with increasing gestation in both groups, irrespective of progesterone supplementation. There was no significant difference in mean nuchal translucency in women supplemented with progesterone compared to those that did not receive progesterone in the first trimester.