What Morning Sickness and Ulcers May Have in Common

From the WebMD Archives

Oct. 17, 2000 -- Helicobacter pylori, the 'bug' that causes many peptic ulcers, may also be the cause of some of the awful bouts of nausea and vomiting that pregnant women know as "morning sickness." That, at least, is what a team of researchers from Ponce School of Medicine in Puerto Rico believe they have found.

But other experts in gastrointestinal diseases are not so convinced, saying it is unlikely that H. pylori is behind what many women consider to be one of the first -- and most unpleasant -- symptoms of pregnancy.

Nilda Santiago, MD, clinical investigator, and Alvaro Reymunde, MD, associate professor at Ponce School of Medicine, tell WebMD that 83% of women referred to a hospital clinic for treatment of severe morning sickness symptoms tested positive for H. pylori.

Several years ago, the infection was shown to be the major cause of stomach ulcers. Currently, patients presenting with ulcers are routinely tested for H. pylori, says Reymunde. If the test is positive, the patients receive antibiotic treatment that wipes out the infection, which in turn allows the ulcer to heal.

In the study presented at the 65th annual scientific meeting of the American College of Gastroenterology in New York, Santiago and Reymunde reported that they also tested a near equal number of pregnant women who reported no morning sickness to determine if H. pylori was present in the blood of those women as well. Both groups of women were in their first three months of pregnancy.

"Only 7% of the healthy controls tested positive for H. pylori," Santiago tells WebMD.

Philip O. Katz, MD, chief of gastroenterology at the Graduate Hospital in Philadelphia, tells WebMD that the study by Santiago and Reymunde is "provocative," but he said he has strong reservations about the findings.

For example, he says, "the prevalence numbers on both ends are surprising." The prevalence of H. pylori in the women without morning sickness is "surprisingly low, while the prevalence in the symptomatic group is surprisingly high." On average, about 20% to 40% of healthy people are carrying silent H. pylori infections -- meaning they have no symptoms, he says, explaining therefore that "finding a prevalence of just 7% is surprising."

Katz says, too, that other studies have linked H. pylori infection to many other conditions but that association always failed to hold up under closer scrutiny. "For example, there was a lot of excitement about a possible link with cardiovascular disease, but when that was studied .. no link was found," he says.

Reymunde says that he and Santiago next plan to test this theory in another study. "We plan to test women who are not pregnant but who are planning a pregnancy. If they are positive, we will treat the H. pylori with antibiotics before the women become pregnant," he says, adding that women cannot undergo the antibiotic treatment during pregnancy because it might harm the fetus.

Asked why some women experience morning sickness during one pregnancy but not during other pregnancies -- even without treatment for H. pylori infection -- Reymunde says, "there are two possible explanations: she could have received antibiotic therapy for another diagnosed infection, such as a sinus infection, so then the H.pylori is eradicated. Or, our study found that 17% of women with morning sickness didn't have H. pylori, so she could be in this group."

While Katz says the H. pylori-morning sickness link requires additional study, he does not support efforts to "go around testing asymptomatic people for H. pylori and then using antibiotics to eradicate an infection that is [inactive]."