Recurrent or threatened
miscarriage
Inadequate production of progesterone in the early part of pregnancy may
be a causative factor in some cases of miscarriage. Progesterone
supplementation, starting in the first trimester, is frequently
prescribed to prevent spontaneous miscarriage and recurrent miscarriage
of unknown etiology.24
A few studies have evaluated the use of oral NMP in the setting of
threatened spontaneous miscarriage in the first trimester (Table
2 ). A retrospective cohort study found that 88% of women with a
threatened spontaneous miscarriage treated with oral NMP 200 mg twice
daily were discharged home with a healthy pregnancy.25A RCT (n = 60) that evaluated first-trimester placental and foetal
volumes showed that oral NMP 400 mg/day had beneficial effects in terms
of significantly increasing placental volume compared to no treatment,
although no significant difference was seen in the live birth rate or
perinatal complications (assessed as secondary
endpoints).26 Finally, a recent comparative RCT (n =
118) found that oral NMP 200 mg twice daily was as effective as
dydrogesterone 10 mg twice daily at reducing bleeding and rate of
miscarriage.27