Does progesterone fluctuation across the menstrual cycle predispose to gastroesophageal reflux?

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. We sought to evaluate the relationship between progesterone concentrations, lower esophageal sphincter pressure (LESP), and acid contact time across the normal menstrual cycle.

LESP, 24-h ambulatory esophageal pH monitoring, and serum progesterone levels were determined in 19 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.

Despite marked oscillations in progesterone levels between the follicular phase (0.37 +/- 0.3 ng/ml) and luteal phase (4.64 +/- 2.92 ng/ml) we observed no significant differences in LESP (29.82 +/- 9.49 vs 30.45 +/- 8.56 mm Hg) or 24-h ambulatory pH levels (pH < 4) in total time (3.04 +/- 0.3% vs 3.18 +/- 2.51%), upright time (4.41 +/- 3.54% vs 4.18 +/- 3.36%), or supine time (0.77 +/- 1.32% vs 1.42 +/- 2.18%).

The fluctuations in progesterone levels across the normal menstrual cycle have no significant impact on LESP and 24-h ambulatory pH parameters. Progesterone, at physiological concentrations, does not predispose to GER in healthy menstruating women.