The return of postpartum fertility monitored by enzyme-immunoassay for salivary progesterone.

A longitudinal study in which daily salivary progesterone and estrone were measured by solid-phase enzyme-immunoassays was performed in 30 postpartum women to monitor the return of ovarian activity. Ovulation was inferred from a sustained rise in salivary progesterone over 251 pmol/l, but salivary estrone measurements were not as informative as progesterone in this regard. Recovery of ovarian activity was slower in lactating women compared with non-lactators; the mean delivery-menstruation interval were 123 (+/- 10) and 57 (+/- 7) days, respectively. An abnormal luteal phase was noted in 35% of the first ovulatory cycles, 20% had short luteal phases and 15% were less than the 5th percentile of a normal control corridor. The pregnancy rate in this study of 3.3% was lower than the anticipated rate of 8.8%. We conclude that salivary progesterone measurements are useful for monitoring the return of ovarian activity postnatally.