Pregnancy and Fertility
A review of the available literature by obstetric researchers found that because pregnancy has increased oxygen demands on the body and, thus, more free radical damage, melatonin supplementation may be a critical consideration for both complicated and normal pregnancies, counter to the traditional stance of avoiding it during pregnancy (1). According to some research, the use of melatonin supplementation during pregnancy, which has been found safe in both mother and fetus according to some research, could prove to help limit complications during critical periods before and shortly after delivery (2,3). A study suggested that preeclampsia does not have a seasonal variation, although it was observed that reduced melatonin levels were associated with the development of preeclampsia (3). Therefore, it has been suggested that melatonin may help support a successful pregnancy.
Pregnancy is a critical time for fetal programming of hypertension. As an antioxidant therapy, melatonin may help prevent hypertension in the offspring of patients with a family history of hypertension (4). It has been hypothesized that oxidative stress negatively impacts fertility. Since melatonin is a strong scavenger of oxidative factors, it could improve both male and female fertility and sperm and oocyte quality, resulting in increased fertilization (5–8). Melatonin shows promise for advanced age infertility and improving IVF outcomes (9–13). A 2024 study found that women with diminished ovarian reserves (DOR) had lower melatonin levels, citing that research in the past year has elucidated melatonin’s role as a potential predictive marker of ovarian health and reserve. Melatonin is present in ovarian follicular fluid and oocytes, serving as an antioxidant and enhancing oocyte maturation, fertilization, and embryo development. The researchers also observed a positive correlation between serum and follicular levels of melatonin and the outcomes of IVF, as has been observed in other studies (14).
Delivery by cesarean may also be associated with higher levels of pro-inflammatory cytokines compared to vaginal birth (15), thereby shunting the production of pineal gland melatonin synthesis and upregulating the tryptophan conversion into the kynurenic pathway, offsetting the serotonin-melatonin pathway (16). Women who delivered vaginally versus by cesarean had higher colostrum melatonin levels (15,17). Finally, administering 10 mg of melatonin, compared with 5 mg or placebo, to women before the cesarean section with spinal anesthesia was shown to reduce the severity of their pain, duration of analgesic use postoperatively, and facilitated their ability to be more physically active in less time after surgery (18).
Some people have expressed concern about whether taking melatonin would result in the shrinkage of reproductive organs, like testes or ovaries, as this phenomenon has been observed in animals that seasonally breed, like hamsters and white-tailed deer. The answer is that melatonin plays a vital role in reproductive health, ensuring the health of the oocyte (egg) and sperm; however, taking melatonin does not lead to these types of reproductive changes in humans, as we are not seasonal breeders. According to some of the melatonin experts that have been consulted with, like world-renowned melatonin researcher Russel Reiter, PhD, and neuroscientist Horacio de la Iglesia, PhD, at the University of Washington, melatonin does not present this issue for humans. In animals that seasonally breed, melatonin alters their reproductive cycles through the year, which is why their reproductive organs change in size as a result. As one might imagine, from a survival point of view, it would not be conducive to certain animals to have offspring at certain times of the year due to cold weather or the lack of food; therefore, melatonin helps set their reproductive rhythm to prime them for favorable fertility outcomes.
Authors: Deanna Minich, Ph.D., Melanie Henning, ND, Catherine Darley, ND, Mona Fahoum, ND, Corey B. Schuler, DC, James Frame
Reviewer: Peer-review in Nutrients Journal
Last updated: October 24, 2024
References
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