Purpose of review: Progesterone is an essential hormone in the process of reproduction. Although the pharmacokinetics and pharmacodynamics of progesterone have been well studied, its use in the pathophysiology of pregnancy remains controversial. One of these concerns is the way in which the hormone is administered.
Recent findings: In obstetrics the most frequent uses of progesterone are in the treatment of threatened abortion, prevention of recurrent miscarriage, or in the support of the luteal phase in assisted reproduction programmes, and in threatened preterm labour. Randomized, controlled trials showed that women who received progesterone were statistically significantly less likely to have recurrent miscarriages before 34 weeks, to have an infant with birth weight of 2.5 kg or lower, or to have an infant diagnosed with intraventricular haemorrhage. There is currently, however, insufficient information to allow recommendations regarding the optimal dose, route and timing of administration of progesterone supplementation.
Summary: Progesterone has shown to be efficacious when continuation of pregnancy is hampered by immunological factors, luteinic and neuroendocrine deficiencies and myometrial hypercontractility. This may explain the reduction in the incidence of preterm birth in high-risk pregnant women using high-dosage prophylactic progesterone.