Lower esophageal sphincter pressure during the normal menstrual cycle.

Lower esophageal sphincter pressure (LESP), basal gastric pH, and plasma levels of gastrin, estradiol, and progesterone were determined in ten women known to have normal menstrual cycles. All determinations were performed both during the follicular phase (Days 2 to 8) and during the luteal phase (Days 20 to 30). In addition, an intraluminal pH probe placed 5 cm. above the lower esophageal sphincter was used to test for the presence of acid reflux in response to three provocative procedures. LESP during the follicular phase was 19.0 +/- 1.5 mm. Hg (mean +/- S.E.M.) and during the luteal phase 16.5 +/- 1.3 mm. Hg (p less than 0.01). Basal gastric pH and plasma gastrin levels were similar at both times. Plasma estradiol in the follicular phase (76.1 +/- 7.0 pg. per milliliter) increased twofold during the luteal phase (159.0 +/- 6.0) (p less than 0.01). Plasma progesterone increased from a level of 1.5 +/- 0.8 ng. per milliliter during the follicular phase to 19.2 +/- 4.2 during the luteal phase. Coincident with these changes in LESP and increases in steroid levels, acid reflux was detected in five women during the luteal phase but was present in only one during the follicular phase.