She heard about Robitussin on one of her TTC forums, which she says operate as unofficial peer-review boards. Immediately after she began taking the stuff, late last year, Jennifer said she noticed a difference in her levels of cervical mucus. After three months, she conceived, although she suffered an early miscarriage. She is certain that Robitussin played a role in helping her get pregnant, however briefly.
"Believe me, I chart whatever I used that month," she said. "There are thousands of women who do the same thing."
Colette Bouchez, a U.S. medical journalist and co-author of the bestselling book Getting Pregnant, believes there are simple remedies that can be effective for certain couples.
"It's not a cure-all for every fertility problem," she said of Robitussin. "If you have a tubal problem, or an infection, or a different type of hormone imbalance, this is not going to help you get pregnant."
The first edition of her book came out in 1988, and has contained a chapter on guaifenesin ever since. She says she has heard hundreds of anecdotes about its effectiveness.
Despite the references to Robitussin in her work, Ms. Bouchez says she has never heard from a pharmaceutical company asking her to share her research, or asking her to stop talking about it.
Those companies are in the business of curing coughs and colds, she said, not addressing infertility. And while the number of women struggling with conception is by no means small, Ms. Bouchez says it is "infinitesimal" compared with the population suffering from coughs and colds. Robitussin reeled in $199-million (U.S.) in 2008 alone.
Besides, she says, guaifenesin's reputation is established, and the blessing of its manufacturers would probably have little impact. "Even if a study comes out and proves it doesn't work, I see women continuing to try for a long time," she said. "The truth is, for many women, it works."