It may not be safe to take melatonin in pregnancy. Melatonin can cause hormonal shifts, increasing the risk of a difficult pregnancy and labor. Melatonin is a naturally occurring hormone that is secreted by the body's pineal gland, which is located in the brain. In women, melatonin influences hormones responsible for reproduction and may also affect the hormones that are responsible for a healthy pregnancy.
Taking supplemental melatonin in pregnancy can alter estrogen, progesterone, and oxytocin levels, which can cause developmental disorders in a fetus. Migraine headaches and insomnia are common pregnancy complaints, and are more pronounced during the third trimester. Even though melatonin has been found to ease migraines and promote sleep, its use in pregnancy has not been deemed safe. In addition, taking melatonin while pregnant can cause gastrointestinal upset, making morning sickness worse.
Other uses of melatonin include alleviating symptoms of jet lag, reducing anxiety, helping with symptoms of anti-anxiety medication withdrawal, and improving platelet count. There is some speculation that taking melatonin supplements may help those suffering from fibromyalgia, ringing in the ears, hot flashes, and irritable bowel syndrome. Taking melatonin during pregnancy might also promote daytime sleepiness, feelings of sadness or depression, and stomach cramps.
Side effects of melatonin include fatigue, vivid dreams, sleepwalking, and gastrointestinal distress. Other side effects may include increased urination or rash. Melatonin might also elevate the risk of seizures. This rare, but important side effect is seen most often in children who have predisposing neurological conditions. Also, people who take melatonin supplements should use caution when operating dangerous machinery or when driving.
Melatonin in pregnancy is also not recommended because it can filter through breast milk, causing adverse effects to the newborn. Women taking melatonin supplements while breastfeeding should monitor their babies for signs of excessive sleepiness, poor muscle tone, vomiting, and lack of coordination. If these symptoms occur, the baby needs emergency medical attention.
Women considering taking melatonin in pregnancy should convey their wishes to their health care providers, who can discuss risks and alternative remedies. For example, women affected by insomnia during pregnancy may want to exercise lightly and avoid products containing caffeine. In addition, managing stress, avoiding alcoholic beverages, and avoiding excessive use of computers and cell phones before bed may also help prevent insomnia. Those who have taken melatonin supplements prior to delivery should tell their health care providers, who can monitor them and their unborn babies during labor.