||Guaifenesin is a mucolytic, a mucus-thinning drug that many say is not very effective when used for respiratory secretions -- might as well just drink water for a cough as take it.|
Human fertility depends on about 8-10 factors all being functional. One or two of these are male, the remainder are aspects of the architecture and function of the female reproductive system. The "cervical factor" usually refers to the penetrability and "friendliness" to sperm of cervical secretions. At least in theory, the mucolytic properties of guaifenisin can thin cervical mucus and make it easier for sperm to make their way to a receptive egg.
This minor change could be an issue for those using natural family planning methods, or relying on progesterone-only hormonal contraceptives, which depend more on the density of cervical mucus for their effectiveness than do estrogen-containing hormonal methods. For someone with slightly "unfriendly" cervical mucus most of the time, it is biologically plausible that guaifenesin's mucus-thinning properties, which can affect the mucus plug of the cervix, could consequently contribute to changes in a woman's ability to conceive. This is the basis on which it has been speculated as a possible pro-fertility agent.
A 1982 journal article1 provides some support for the idea that guaifenesin may have the potential to increase fertility in some people. Guaifenesin's potential as a pro-fertility agent is also mentioned in a popular book about fertility awareness by Toni Weschler, but the author does not cite specific references showing that guaifenesin actually improves female fertility.2 Beyond these sources, there appears to be little definitive research in this area.
- Check JH, Adelson HG, Wu C-H. "Improvement of cervical factor with guaifenesin". Fertility and Sterility. 1982;37:5.
- Weschler T. Taking Charge of Your Fertility: The Definitive Guide to Natural Birth Control and Pregnancy Achievement. 1995. Harper Perennial. 156-157.