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Coffee & the Reproductive System

Jun 21, 2011 | By Mary Krane Derr
Coffee & the Reproductive System
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As dietitian Karen Collins documents in "A Cup of Confusion," her Jan. 17, 2007 report on MSNBC, conflicting research studies have caused public uncertainty over whether coffee harms or benefits human health, including reproductive health. For example, a 2003 British Medical Journal paper associates high maternal coffee consumption with increased stillbirths. At the same time, industry-funded websites like Coffee and Health claim that moderate coffee consumption does not demonstrably harm reproductive health. Without contradicting this claim, the scientific literature does link high consumption to several reproductive problems and--in one intriguing case--a reproductive benefit.

Active Compounds in Coffee

Roasted coffee contains more than 1,000 compounds. The best known and most studied of these is caffeine, yet scientists are only beginning to understand its effects on the human body. Also found in tea, yerba mate and other beverages, caffeine belongs to the methylxanthines, a family of chemicals that humans use as stimulants.

Female Fertility and Pregnancy

The 2010 review "Methylxanthines and Reproduction" in the "Handbook of Experimental Pharmacology" suggests an association between high daily caffeine consumption--500 mg or more than six cups of coffee--and delayed first pregnancies. Caffeine might inhibit muscle movements in the Fallopian tubes, according to a 2011 study in the "British Journal of Pharmacology." So it could hinder fertilization of the egg and transport of the embryo into the uterus, which is necessary for implantation and further development.

Fetal and Postnatal Development

In Western nations, more than 80 percent of the population is exposed to caffeine. The 2010 "Handbook of Experimental Pharmacology" review "Methylxanthines During Pregnancy and Early Postnatal Life" was inconclusive about the effects of low to moderate caffeine exposure upon human fetuses and newborns. Research from the June 2010 "American Journal of Clinical Nutrition" did not find that low to moderate caffeine consumption harmed fetuses. However, high consumption--more than 540 mg per day--was associated with reduced fetal lengths and weights.

Male Reproductive Health

According to "Methylxanthines and Reproduction," studies conflict over whether caffeine impairs sperm production. However, as of 2011, no relationship has been found between "moderate daily caffeine consumption of up to 400-450 mg a day" and human male infertility. A 2011 "Bio Med Central Cancer" scientific literature review found no association between elevated cancer risk and coffee drinking. In fact, coffee consumption was associated with lower rates of common malignancies like prostate cancer. According to a study in the May 18, 2011 "Journal of the National Cancer Institute," men who drank six or more cups of coffee daily had 60 percent less risk of fatal prostate cancer and 18 percent less risk of prostate cancer altogether.

Intake Recommendations

According to MedlinePlus, in general, "three eight-ounce cups of coffee (about 250 mg of caffeine) per day is considered an average or moderate amount of caffeine." However, the March of Dimes recommends that women trying to conceive and pregnant women consume no more than 200 mg of caffeine daily. This equals the amount in an average 12-ounce coffee. Breastfeeding women should take in no more than the caffeine in two to three cups of coffee daily. As of 2011, no clinical recommendations on caffeine have been established for men trying to conceive or prevent prostate cancer. Ask your doctor about your personal daily limits on coffee and caffeine.

References

Article reviewed by Mike Batista Last updated on: Jun 21, 2011

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