The effect of small doses of progesterone released from two types of vaginal rings on ovarian activity and bleeding patterns during the first postpartum year.

A total of 20 breastfeeding women used progesterone-releasing vaginal rings for up to 12 months. The women were divided into two groups, one (n = 9) using rings with an initial release rate of 5 mg/24 h, the other (n = 11) with a release rate of 20 mg/24 h. Individual women started to give breast milk supplements and ceased to breastfeed after various periods of time. Urinary estrone and pregnanediol glucuronide levels were measured by radioimmunoassay three times weekly during the entire trial. Individual diary cards were used to register bleeding and spotting. A significantly higher concentration of pregnanediol glucuronide was seen when the 20 mg/24 h ring was used in the lactation period, in comparison with the 5 mg/24 h ring. In the post-lactation period, pregnanediol glucuronide levels dropped when the 20 mg/24 h ring was used. Estrone glucuronide levels increased after the termination of breastfeeding, indicating an enhanced suppression of ovarian activity in the lactation period with both rings. Although the degree of suppression was dose-related, both rings were likely to offer a sufficient contraceptive effect in the lactation period. No significant changes were observed when milk supplements were added to breastfeeding. The use of the 20 mg/24 h ring resulted in a much better bleeding pattern (significantly less bleeding days) than the 5 mg/24 h ring during the lactation period. In the post-lactation period, the 20 mg/24 h ring the bleeding because much worse than in the lactation period.(ABSTRACT TRUNCATED AT 250 WORDS)