Melatonin and melatonin-progestin combinations alter pituitary-ovarian function in women and can inhibit ovulation.
Level 3 - non-randomized controlled study
Non-randomized controlled clinical trial with untreated parallel controls
PubMed 1727807 · doi:10.1210/jcem.74.1.1727807
What was done
Researchers evaluated the effects of high-dose melatonin (MEL) alone and in combination with the synthetic progestin norethisterone (NET) on pituitary-ovarian function in 32 women compared with 8 nonmedicated controls. Twelve women received 300 mg MEL daily for 4 months (8 women on days 1–30, 4 women on days 5–17). Sixteen women received one of four combinations of MEL (7.5–300 mg) and NET (0.30–0.75 mg) on cycle days 1–21 for 4 months (4 women per group). Four additional women received either 300 mg MEL alone (n = 2) or 300 mg MEL plus 0.15 mg NET (n = 2) on days 1–21 for 2 months. Serum levels of LH, FSH, estradiol (E2), and progesterone (P4) were measured at regular intervals.
What was found
Compared to 8 nonmedicated controls, daily administration of 300 mg MEL (days 1–30) significantly decreased mean LH levels over 4 months (P < 0.001) and inhibited P4 in the first and fourth months (P < 0.001), with LH and E2 inhibition reaching significance in the fourth month (P < 0.005). Treatment with 300 mg MEL on days 5–17 and 75 mg MEL combined with 0.30 mg NET also significantly decreased LH, E2, and P4 in the first and fourth medication months (P < 0.05). No alterations in sleep-wake rhythms or adverse side effects were observed.
Why it matters
This study demonstrates that pharmacological doses of melatonin can suppress gonadotropins and ovarian steroidogenesis in women, suggesting a potential role for melatonin-progestin combinations in hormonal contraception.
Limits
The study had a small overall sample size with tiny subgroups (2 to 8 women per arm). It was non-randomized, lacked a blinded placebo control, and did not evaluate real-world contraceptive efficacy.
Cited by
- partial High doses of melatonin act as a contraceptive.