The relationship between exogenous progesterone administration in the first- trimester pregnancy and fetal nuchal translucency thickness

Abstract Introduction: Increased fetal nuchal translucency (NT) thickness is defined as a transient subcutaneous accumulation of fluid behind the fetal neck that can be seen with the help of ultrasound. The thickness of fetal NT is a diagnostic criterion in genetic syndromes. The aim of this study was to investigate the relationship between exogenous progesterone administration in the first trimester of pregnancy and fetal NT thickness.Materials and Methods: This retrospective cohort study was conducted on 200 pregnant women aged 18 to 45 years including 100 pregnant women receiving exogenous progesterone due to vaginal bleeding in the first trimester and 100 pregnant women who did not receive exogenous progesterone from February 2021 to November 2021. The NT thickness of their fetal was measured at 11 to 12 weeks-6 days of gestation. Data were analyzed using Stata software version 14 using independent t-test, Chi-square, Fisher, and Pearson correlation coefficient. The statistical significance level was determined as less than 0.05 (P <0.05).Results: Mean of age, body mass index (BMI), gestational age (GA), crown-rump length (CRL), pregnancy-associated plasma protein-A (PAPP-A), free beta-human chorionic gonadotropin (FβHCG) and βHCG median and multiple of median (MOM) levels were not statistically significant in the two groups (p<0.05).The mean of NT thickness in the group receiving exogenous progesterone was higher than the group non-receiving exogenous progesterone and there was a significant difference between the two groups (p<0.05). Frequency distribution of Gravida, parity, previous live births, previous abortion, and history of abnormalities were not significant in the two groups (p<0.05). Conclusion: Although the findings of the present study showed that external progesterone consumption increased the thickness of the fetal nuchal translucency thickness, no anomaly was observed in delivered babies.