No trial has reported long-term follow-up of progesterone treatment in recurrent miscarriage; therefore, the long-term safety of progesterone supplementation is still not well known.[11] However, there is no evidence that progesterone causes anatomical or physiological abnormalities in the fetus. Natural progesterone suppresses myometrial contractility, unlike the progestin 17-alpha hydroxyprogesterone caproate (17-OHPC) which does not have this effect and at high concentration may stimulate myometrial contractility.[10] No trial has reported long-term follow-up of the use of progesterone for recurrent miscarriage, therefore the safety of progesterone supplementation is still not well known.[11] However, there is no evidence that progesterone causes anatomical or physiological abnormalities in the fetus. Is there evidence of any fetal abnormalities with oral progesterone supplementation in pregna... Dydrogesterone is a retroprogesterone and its selectivity for the progesterone receptor is very high. Therefore, support with progesterone may help to establish a sufficient immune response in early pregnancy and prevent miscarriage.[7] Progestogens available on the market are classified as either natural or synthetic.[[8]] Synthetic progestogens (progestins) do not correlate with natural progesterone and are artificially manufactured in a laboratory. [Extracted from the article]