Is progestogen supplementation necessary to prevent abortion?

A prospective study was conducted to evaluate the effect of progestogens on the pregnancy outcome of threatened abortion (TA). A total of 251 pregnant women less than 20 weeks of gestational age (GA) were included. Group 1 consisted of women with vaginal bleeding who had already been under treatment with progestogens and Group 2 was composed of women with vaginal bleeding who were only followed without progestogen therapy, whereas Group 3 was the control group without any vaginal bleeding or progestogen therapy. The pregnancy outcomes and serum progesterone levels were compared among the groups. The mean serum progesterone concentrations were statistically significantly higher in Group 1 in comparison to Group 2 and 3 (p < 0.001). Abortion rates were similar among the study groups. Although progestogen supplementation leads to increased level of serum progesterone, this finding does not translate to its beneficial effect on the pregnancy outcomes in cases of TAs.