Alterations in saliva steroid hormone levels after oral mifepristone administration in women with pregnancies of greater than 41 weeks' gestation

Abstract

The objective of this study is to describe the effects of oral mifepristone administration on saliva levels of estradiol, estriol, progesterone, and cortisol in women with postdates pregnancy. As an adjunct to a randomized controlled trial comparing 200 mg oral mifepristone to placebo for cervical ripening and labor induction in women with pregnancies greater than 41 weeks' gestation, saliva samples were obtained before drug administration and every 6 hours thereafter for 24 hours. Estradiol, estriol, progesterone, and cortisol levels were measured by radioimmunoassay. Ninety-seven participants received mifepristone, and 83 received placebo. Saliva steroid hormone data were available for 71 mifepristone-and 60 placebo-treated women. Mean baseline saliva estradiol, estriol, progesterone, and cortisol levels were similar between study groups. At 24 hours after study medication administration, saliva estradiol, estriol, progesterone, and cortisol levels in the mifepristone group were significantly elevated compared with baseline. There was no significant change in hormone levels in the placebo group. Oral mifepristone significantly increased saliva estradiol, estriol, progesterone, and cortisol compared with placebo. This may reflect mifepristone's antiglucocorticoid properties. These hormone elevations may contribute to the mechanism by which mifepristone causes cervical ripening and increases myometrial activity.