Can Women Conceive Faster With Amino-Acid Based Products?

No published studies show increases in pregnancy rates

By Laura Johannes
Nov. 16, 2015 

The Ache: Even without fertility problems, women can easily take six months or a year to get pregnant, physicians say.

The Claim: Natural amino-acid based products that thin cervical fluid can make it easier for some women to get pregnant by helping the sperm reach the egg to fertilize it, say companies that sell the products. The products are a natural alternative to cough syrup, which thins secretions and has long been a folk remedy to aid conception.

The Verdict: One of the ingredients of the natural products is N-acetylcysteine, or NAC, has been shown to help achieve pregnancy in women with a hormonal disorder called polycystic ovary syndrome. However, scientists say there are no published studies showing that NAC or any of the natural products improve pregnancy rates in normal women.

Products aimed at thinning cervical fluid likely won’t help if women have a significant fertility issue, such as poor ovulation, and “there is definitely no evidence that this approach makes sense for normal women,” says William Schoolcraft, medical director of the Colorado Center for Reproductive Medicine, a Denver fertility clinic. A test that examines the quality of cervical fluid under a microscope, called the postcoital test, hasn’t proved a good predictor of whether a woman will get pregnant, he adds.

The natural products, including FertileCM from Fairhaven Health LLC, Bellingham, Wash., and PregPrep from PregPrep LLC of New York, are based on the idea that improving the quality of fluid produced by the cervix can improve the chances of getting pregnant. Fertile CM has been sold since 2005; PregPrep hit the market in 2012 and has recently gained wide distribution.

When a woman is in her fertile phase, cervical fluid ideally becomes thin and stretchy, with the consistency of an egg white, allowing the sperm to swim freely, says FertileCM inventor Amos Grunebaum, director of obstetrics and chief of labor and delivery at NewYork-Presbyterian/Weill Cornell Medical Center in New York. For a variety of reasons, such as poor nutrition or other medications, a woman’s cervical fluid around the time of ovulation may be thick and “hostile” to pregnancy, he adds.

Neither PregPrep nor FertileCM have performed clinical studies on the products; both companies say positive feedback from customers suggests their products are effective.

Some cough syrups contain guaifenesin, an ingredient designed to loosen chest congestion. Its use as an aid to getting pregnant surfaced in the medical literature in 1982 when a small, noncontrolled study found it may help conception by thinning cervical fluid. Study co-author Jerome Check, head of the division of reproductive endocrinology and infertility at Cooper Medical School of Rowan University, Camden, N.J., says he hasn’t followed up his work with a larger, more rigorously designed study, but says he still recommends guaifenesin as a conception aid. Any thinning agent, he adds, will only make a difference if a woman is having trouble conceiving due to overly thick cervical fluid, which Dr. Check estimates at 3% of women.

NAC, a form of the amino acid cysteine offered as part of the PregPrep Complete Conception Kit, is a proven therapy for thinning respiratory-tract secretions in cystic fibrosis patients. Lara Oboler, chief medical adviser of PregPrep, says she doesn’t know of any studies showing it thins cervical fluid, but it is logical that it would have the same biochemical action as it does in the lungs. In cystic fibrosis patients, NAC is often given as a mist. PregPrep, $29.99, includes 14 NAC tablets, to be taken twice a day for the five days before ovulation begins and the following two days, and a month’s supply of prenatal vitamins.

Dr. Oboler, a cardiologist who co-invented the product after taking cough syrup to speed her own pregnancy, adds that studies have found that NAC improves the chance of pregnancy in women with PCOS. In an article published earlier this year in the journal Obstetrics and Gynecology International, a review of eight studies involving a total of 910 women concluded that women with PCOS who took NAC had a greater chance of getting pregnant than those who took a placebo.

The benefit to these women was likely due to the fact that NAC aids insulin sensitivity, often a problem in women with PCOS, and also acts to thicken the endometrial lining, says study co-author Amit Raval, who worked on the study while at West Virginia University and is currently a senior researcher at Wilmington, Del., health-care-consulting firm HealthCore. The study’s conclusions apply only to women with PCOS, which affects an estimated 5% to 15% of women of reproductive age, he adds.

The main ingredient of FertileCM, $19.95 for a month’s supply, is l-arginine, an amino acid which is used by the body to synthesize nitric oxide, a compound important for many processes in the body. Nitric oxide in turn improves circulation to reproductive areas, which can increase the amount and quality of cervical fluid, says Dr. Grunebaum, who works as a paid consultant to Fairhaven and receives royalties on product sales.