Progesterone can help with recurring miscarriages

Recurrent abortions are defined as such when the woman has to face more than two consecutively.

The causes of recurrent miscarriages are many and there are some factors that increase the risk of their occurrence. The most common risk factors are cytogenetic problems, related to the morphology of the uterus, endocrine, haematological, metabolic, and also immunological abnormalities.

In almost half of all cases of recurrent miscarriages not even a careful evaluation is able to trace precisely the causes. In these cases, to try to keep the pregnancy going, the woman undergoes empirical treatments, for example with aspirin, heparin, and progestogens.

In a new review of the studies published in Fertility And Sterility in April 2017, the effect of progesterone was examined in women with a history of recurrent miscarriages.

The meta-analysis considered 10 randomized controlled trials involving a total of 1586 patients. We evaluated the effects of synthetic or natural progesterone in patients with a history of recurrent miscarriages versus patients who received no treatment or placebo.

Women who took progesterone in the first trimester had a lower risk of losing their pregnancy. Furthermore, progestin supplementation had no impact on the incidence of preterm delivery, neonatal mortality, or fetal genital abnormalities.

A further analysis showed that the administration of progesterone orally, intramuscularly and synthetic progesterone was associated with a reduction in miscarriage rates. Vaginal administration of progesterone and natural progesterone did not influence miscarriage rates.

Intramuscular injections of 17-alpha hydroxyprogesterone caproate and oral administration of dydrogesterone were both associated with a significant reduction in the risk of miscarriage.

Based on these findings, the authors concluded that synthetic progestogens, but not natural progesterone, are associated with a lower risk of miscarriage among women with a history of unexplained re-miscarriages. 

The role of progesterone

Progesterone secreted initially by the corpus luteum and then by the placenta is a key hormone during pregnancy: it is required for the implantation and maintenance of the pregnancy . Furthermore, it has some immunomodulatory effects which could further influence the receptivity of the endometrium.

Although this meta-analysis supports the use of synthetic progestogens in women with recurrent miscarriages of unknown cause, further studies are needed.

When should progesterone treatment be started?

What is the optimal dose and duration of treatment?

These questions need answers in order to provide adequate supportive care. Until these results are available, according to the authors of the meta-analysis, synthetic progestogens should be prescribed to women with recurrent unexplained miscarriages, starting from when the pregnancy is confirmed.