Progesterone

The Basics

What is Progesterone?

Used as a part of hormone replacement therapy in postmenopausal women who have not had a hysterectomy (surgery to remove the uterus). Hormone replacement therapy usually includes estrogen, which is used to treat symptoms of menopause and reduce the risk of developing certain diseases by helping to prevent the thickening of the uterine lining and decrease the risk of developing uterine cancer. Progesterone is also used to bring on menstruation.

Brand names for Progesterone

Prometrium

How Progesterone is classified

Hormones, Progesterone Congeners

Progesterone During Pregnancy

Progesterone pregnancy category

Category BNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Progesterone while pregnant

Reproductive studies have been performed in mice at doses up to 9 times the human oral dose, in rats at doses up to 44 times the human oral dose, in rabbits at a dose of 10 mcg/day delivered locally within the uterus by an implanted device, in guinea pigs at doses of approximately one-half the human oral dose and in rhesus monkeys at doses approximately the human dose, all based on body surface area, and have revealed little or no evidence of impaired fertility or harm to the fetus due to progesterone.

Taking Progesterone While Breastfeeding

What are recommendations for lactation if you're taking Progesterone?

Release from the progesterone-releasing intrauterine device available in the United States is 65 mcg/day or only 0.65% of the dose released from most of the devices reported in the literature. Because of the low levels of progesterone in breastmilk, even with the high-dose products, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. The progesterone vaginal ring available in some countries produces maternal blood levels that are lower than those of ovulating women.[1] Most studies indicate that progesterone is not detrimental to milk production or duration of nursing.[2][3] No special precautions appear to be required. In Russia, a progesterone gel (Progestogel – Besins Healthcare; not available in the US) has been used topically as a one-time application to the breasts to treat postpartum breast engorgement when more conservative measures have failed.[4] A subsequent study failed to detect any decrease in breast hardness 20 minutes after application of progesterone gel in mothers with engorgement.[5] The safety and efficacy of this use have not been well studied and the manufacturer of Progestogel recommends avoiding its use during lactation.

Maternal / infant drug levels

Release from the progesterone-releasing intrauterine device available in the United States is 65 mcg/day or only 0.65% of the dose released from most of the devices reported in the literature. Because of the low levels of progesterone in breastmilk, even with the high-dose products, amounts ingested by the infant are small and would not be expected to cause any adverse effects in breastfed infants. The progesterone vaginal ring available in some countries produces maternal blood levels that are lower than those of ovulating women.[1] Most studies indicate that progesterone is not detrimental to milk production or duration of nursing.[2][3] No special precautions appear to be required. In Russia, a progesterone gel (Progestogel – Besins Healthcare; not available in the US) has been used topically as a one-time application to the breasts to treat postpartum breast engorgement when more conservative measures have failed.[4] A subsequent study failed to detect any decrease in breast hardness 20 minutes after application of progesterone gel in mothers with engorgement.[5] The safety and efficacy of this use have not been well studied and the manufacturer of Progestogel recommends avoiding its use during lactation.

Possible effects of Progesterone on milk supply

Eighty-four women had 6 subdermal implants containing 100 mg each of progesterone inserted between days 30 to 35 postpartum as a contraceptive. Compared to women who received either a placebo or a Copper T intrauterine device, no difference was found in the breastfeeding rates during the first 9 months postpartum. At 1 year postpartum, more women in the Copper T group were breastfeeding than in the progesterone or placebo groups.[8]

Vaginal rings that released progesterone were inserted at about 60 days postpartum in 246 women. The 3 types of rings released progesterone either 5, 10 or 15 mg daily. Control women received a Copper T intrauterine device. At 6 and 12 months postpartum there was no significant difference in the percentage of infants who were breastfed between the progesterone and Copper T groups.[16]

One hundred twenty breastfeeding women used a vaginal ring that released about 10 mg daily of progesterone, starting during weeks 5 to 7 postpartum. The rate of weaning was greater in the progesterone ring group than in groups of women who received levonorgestrel or norethindrone implants for postpartum contraception.[11]

In a multicenter study, 802 women who received a vaginal ring that released about 10 mg daily of progesterone were compared to 734 women who received a Copper T intrauterine device beginning at day 29 to 63 postpartum. No differences were found in the rate of breastfeeding between the 2 groups over the first year postpartum.[17]

Two hundred eighty-five women who received a vaginal ring that released about 10 mg daily of progesterone were compared to 262 women who received a Copper T intrauterine device beginning between weeks 5 and 9 postpartum. No differences in the breastfeeding rates were seen between the 2 groups during the 14-month observation period.[14]

An observational study followed 192 women who used a vaginal ring that released 10 mg of progesterone daily beginning between days 54 and 64 postpartum. All subjects used the vaginal ring for at least 4 months; 90% were still using it at 6 months and 73% were using it at 9 months postpartum. The duration of breastfeeding and infant growth were similar to reference groups.[18]

A double-blind placebo-controlled trial randomized 46 postpartum women who were abstinent former smokers to oral micronized progesterone 200 mg twice a day or placebo for 4 weeks to assess smoking abstinence rates. Entry into the study occurred only after breastfeeding was well established. No statistical difference was found in the number of days of breastfeeding between the groups.[19]

Possible alternatives to Progesterone

(Contraception) Etonogestrel, Intrauterine Copper Contraceptive, Levonorgestrel Implant, Intrauterine Levonorgestrel, Medroxyprogesterone Acetate.