Prospective study of 6 women with singleton pregnancies 18 0/7- 23 6/7 weeks' gestation with no prior preterm birth or short cervix who are administered a single dose of 200mg vaginal progesterone suppository. Serum progesterone levels will be drawn serially from pre-dose to 24 hours post-dose.
Pharmacokinetic analysis of 200mg vaginal progesterone suppository in women with singleton pregnancies between 18 0/7- 23 6/7 weeks' gestation