Serum progesterone and 17-hydroxyprogesterone in the diagnosis of ectopic pregnancies and the value of progesterone replacement in intrauterine pregnancies when serum progesterone levels are low.

The corpus luteum function was evaluated in patients with surgically confirmed ectopic pregnancy (EP) in a multicenter study. In addition, the minimal threshold of serum progesterone (P) concentration required for salvaging intrauterine pregnancies (IUP) was also examined. Results show that single P or 17-OHP measurements are not diagnostic for EP, since mean P levels in EP were similar to those with spontaneous abortion though significantly lower than those in controls. 17-OHP levels in EP overlapped in 50% with IUP, and the mean levels were significantly lower only at 6-7 weeks. The 17-OHP levels when compared to hCG supports the view that corpus luteum defect is primary. In IUP, P levels < 8 ng/ml still were associated with viable (60%) pregnancy; thus no minimal threshold could be established.