Progesterone supplementation in women with otherwise unexplained recurrent miscarriages

Recurrent miscarriages, the loss of three or more consecutive intrauterine pregnancies before 20 weeks of gestation with the same partner, affect 1%-1.5% of the pregnant population. The inadequate secretion of progesterone in early pregnancy has been proposed as a cause of recurrent miscarriages.

The aim was to investigate the efficacy of progesterone supplementation in patients with unexplained recurrent miscarriages.

This was a 9-year cohort study of women with otherwise unexplained recurrent miscarriages who attended a recurrent miscarriage clinic in a tertiary care university hospital.

Women with at least three unexplained recurrent miscarriages were included in the study. They were divided into three groups according to their initial and 48-h repeat progesterone levels. For women with inadequate endogenous progesterone secretion, natural progesterone vaginal pessaries 400 mg 12-hourly were offered until 12 weeks gestation.

Proportions and 95% confidence intervals calculated for categorical variables and the chi-square test were used to show statistical significance. Medians and ranges were calculated for noncontinuous variables.

Pregnancy cycles (n = 203) were analyzed to examine the miscarriage rate following progesterone supplementation. Overall live birth and miscarriage rates were 63% and 36%, respectively. When analyzed by the number of previous miscarriages there was a reduction in the miscarriage rate following progesterone supplementation in women with 4 previous miscarriages when compared with historical data.

Progesterone supplementation may have beneficial effects in women with otherwise unexplained recurrent miscarriages.