Gastroesophageal reflux (GER) occurs in 30-50% of all pregnancies. The progressive rise in plasma progesterone has been suggested as a possible mediator of GER during pregnancy. It is not known whether progesterone, at physiological concentrations, has an effect on acid contact time. The study includes 70 women--50 pregnant and 20 non pregnant healthy menstruating female volunteers. We used immunoenzymatic tests for determination of estradiol, progesterone and beta HCG hormones during pregnancy. The 50 pregnant women with GER symptoms heartburn, acid regurgitations had increased levels of steroid hormones. 24-h ambulatory esophageal pH monitoring and serum progesterone levels were determined in 20 healthy women known to have normal menstrual cycles. All tests were performed during the follicular phase days 2-7 and the luteal phase days 22-28 of one or two consecutive menstrual cycles. The fluctuations in progesterone levels across the normal menstrual cycle have no significant impact on 24-h ambulatory pH parameters.
Conclusions: Progesterone, at physiological concentrations, does not predispose to GER in healthy menstruating women. Thus, it is likely that if progesterone, with or without estrogen, contributes to GER in pregnancy, this effect takes place only at the high concentrations observed during this condition. After delivery, GER disappear with decreasing hormonal levels and uterine volume.