Determinants of pregnancy heartburn.

OBJECTIVE: To study the prevalence and severity of reflux symptoms in pregnancy.

DESIGN: Self-administered questionnaire detailing age, race, gestational age, parity, weight, height, symptoms and severity of gastro-oesophageal reflux.

SETTING: An antenatal clinic in a teaching hospital.

SUBJECTS: 607 consecutive women at various stages of pregnancy were recruited during attendance at antenatal clinic.

RESULTS: The prevalence of heartburn increased with gestational age (22% in the first, 39% in the second, and 72% in the third trimester; P < 0.0001), as did severity of heartburn (P < 0.0001). Pharyngeal regurgitation as a symptom showed little increase during advancing pregnancy. Symptoms of heartburn rapidly increased towards the end of the second trimester. The decrease in heartburn traditionally expected during the last three weeks of pregnancy (fetal head descent) was not observed. Logistic regression analysis showed increased risk of suffering heartburn with increasing gestational age (P < 0.0001), pre-pregnancy heartburn (P < 0.0001), parity (P < 0.0001) and inversely with maternal age (P < 0.05) but not with body mass index before pregnancy, race, or weight gain in pregnancy.

CONCLUSION: Heartburn, but less so pharyngeal regurgitation, increases in prevalence and severity with gestational age and parity. We speculate that hormone-related impairment of distal oesophageal clearance mechanisms may have a crucial bearing on whether heartburn develops in those individuals at greatest risk.