Helicobacter pylori infection: a predictor of vomiting severity in pregnancy and adverse birth outcome

BACKGROUND: Nausea and occasional vomiting in early pregnancy is common. Why some women experience severe nausea and occasional vomiting in early pregnancy is unknown. Causes are multifactorial and only symptomatic treatment options are available, although adverse birth outcomes have been described. Helicobacter pylori infection has been implicated in the cause of nausea and occasional vomiting in early pregnancy. OBJECTIVE: The purpose of this study was to investigate the association of H pylori with vomiting severity in pregnancy and its effect on birth outcome. STUDY DESIGN: We assembled a population-based prospective cohort of pregnant women in The Netherlands. Enrolment took place between 2002 and 2006. H pylori serology was determined in mid gestation. Women reported whether they experienced vomiting in early, mid, and late gestation. Maternal weight was measured in the same time periods. Birth outcomes were obtained from medical records. Main outcome measures were vomiting frequency (no, occasional, daily) and duration (early, mid, late gestation), maternal weight gain, birthweight, small for gestational age, and prematurity. Data were analyzed with the use of multivariate regression. RESULTS: We included 5549 Women, of whom 1932 (34.8%) reported occasional vomiting and 601 (10.8%) reported daily vomiting. Women who were H pylori-positive (n=2363) were more likely to report daily vomiting (adjusted odds ratio, 1.44; 95% confidence interval, 1.16-1.78). H pylori positivity was associated with a reduction of total weight gain in women with daily vomiting (adjusted difference, -2.1 kg; 95% confidence interval, -2.7 to -1.5); infants born to women with H pylori and daily vomiting had slightly reduced birthweight (adjusted difference -60g; 95% confidence interval, -109 - -12) and an increased risk of being small for gestational age (adjusted odds ratio, 1.49; 95% confidence interval, 1.04-2.14). H pylori and daily vomiting did not significantly affect prematurity rate. CONCLUSION: This study suggests that H pylori is an independent risk factor for vomiting in pregnancy. In women with daily vomiting, H pylori is also associated with low maternal weight gain, reduced birth weight, and small for gestational age. Because effective treatments for severe nausea and occasional vomiting in early pregnancy are currently lacking, the effect of H pylori eradication therapy on nausea and occasional vomiting in early pregnancy symptom severity should be the target of future studies.