A clinical study was designed to test whether sustained administration of progesterone to nursing mothers could prolong lactation and delay the postpartum recovery of fertility. The hormone was administered by subdermal implantation of six pellets that each contained 100 mg of progesterone. This treatment was administered to 84 fully nursing women on day 30 post partum. Control groups were composed of 130 fully nursing women who received an injectably placebo, and by 125 fully nursing women who received a TCu 200 intrauterine contraceptive device. An exacting list of requirements for admission to and continuation in the study was applied to all groups. No pregnancies occurred in the progesterone-treated group from the second to the sixth postpartum month. This period coincided with the period of elevation plasma progesterone attributable to hormone released from the implants. The cumulative probability of pregnancy in the placebo group was 10.2 per 100 women at the sixth month. Treatment with progesterone did not change the duration of lactation or the rate of child growth, and no adverse effects were recorded. These results warrant further investagation of the use of progesterone as an alternative method to prevent conception in nursing women.
PIP: A clinical study was conducted to test whether sustained administration of progesterone to nursing mothers could prolong lactation and delay the postpartum recovery of fertility. Study participants were living in the Central Area of Santiago, Chile at the time of delivery. The hormone was administered by subdermal implantation of 6 pellets that each contained 100 mg of progesterone. This treatment was administered to 84 fully nursing women on day 30 postpartum. Control groups were composed of 130 fully nursing women who received an injectable placebo, and by 125 fully nursing women who received a TCu 200 IUD. An exacting list of requirements for admission to and continuation in the study was applied to all groups. No pregnancies occurred in the progesterone treated group from the 2nd to the 6th postpartum month. This period coincided with the period of elevated plasma progesterone attributable to hormmone released from the implants. The cumulative probability of pregnancy in the placebo group was 10.2/100 women at the 6th month. Pregnancy was the most frequent reason for termination from the 7th month to the 12th postpartum months in the progesterone and the placebo groups, both of which had a higher number of terminations than the copper T group. The proportion of women in full nursing ranged from 51.2 to 58.3 at the 6th postpartum month and from 10.7 to 17.6 at the end of the year. At the 12th month the IUD group had the highest percentage of women in full nursing and the lowest percentage of terminations. In regard to child growth, there were no significant differences between the 3 groups at any month when the averages were analyzed by Student's t test. In sum, treatment with progesterone did not change the duration of lactation or the rate of child growth. No adverse effects were recorded. Bleeding patterns were similar in the 3 groups. The local tolerance to pellets was good, and no clinical or laboratory side effects were detected. Results obtained with progesterone pellets are encouraging. Further study is needed to confirm their efficacy and acceptability.