The effects of exogenous oral micronized progesterone on first trimester aneuploidy screening markers in women with threatened miscarriage: a matched case control study.

<bold>Objectives: </bold>To evaluate the effect of using progesterone due to early vaginal bleeding on aneuploidy screening markers in the first trimester.<bold>Material and Methods: </bold>This case control study includes the pregnant women who applied to our clinic in order to have a screening test for Down syndrome in the weeks of 11°/7-136/7. The patients were divided into three groups. Self reported vaginal bleeding with progesterone therapy (Bl+, Prg+, n:70), Self reported vaginal bleeding without progesterone therapy (Bl+, Prg-, n:70) and as a control group pregnant women who had no vaginal bleeding. (NoBl, NoPrg, n:70). In all patients, free beta-human chorionic gonadotrophin (β-hCG), pregnancy associated plasma protein-A (PAPP-A) levels and nuchal translucency (NT) thickness were analyzed. Mean MoMs of the markers were compared between three groups.<bold>Results: </bold>In the two groups with vaginal bleeding (Bl+, Prg + and Bl+, Prg-) the free β-Hcg MoM values were statistically higher (1.22 ± 0.72, 0.98 ± 0.45, respectively) compared to the No Bleeding/No Progesterone group (0.81 ± 0.52) (p ≤ 0.001, p ≤ .01, respectively). However, no significant difference was found between the free β-hCG MoM value of women with Bl+, Prg + group (1.22 ± 0.72) and Bl+, Prg - group (0.98 ± 0.45). (p: .053, significance level limitation with Bonferroni correction p: .017). PAPP-A and NT thickness did not differ significantly between the groups.<bold>Conclusion: </bold>Our data did not find an association between the use of oral progesterone and any alternations in first trimester screening parameters. Regardless of the progesterone usage, vaginal bleeding in the first trimester pregnancies increased the free β-hCG MoM values compared to pregnancies without vaginal bleeding during pregnancy. [ABSTRACT FROM AUTHOR]