Gastro-oesophageal reflux in pregnancy. Altered function of the barrier to reflux in asymptomatic women during early pregnancy.

The object of this study was to investigate the effect of early pregnancy on the competence of the barrier to gastro-oesophageal reflux (GOR). Oesophageal manometry and prolonged intra-oesophageal pH monitoring were carried out in 12 asymptomatic pregnant women and in 7 non-pregnant women. There was no significant difference in mean intragastric pressure between these two groups. However, both mean lower oesophageal sphincter (LOS) pressure and mean barrier pressure (LOS pressure minus intragastric pressure) were significantly lower in the pregnant subjects (16.9 +/- 0.79 mm Hg; 8.69 +/- 0.73 mm Hg) than in the controls (21.5 +/- 1.93 mm Hg; 14.1 +/- 1.22 mm Hg) (p less than 0.01 and less than 0.001, respectively). No significant difference could be demonstrated between the two groups with regard to degree of GOR, although the pregnant women did exhibit a tendency towards more marked reflux. The results indicate a diminution in the barrier to reflux in early pregnancy due to a reduction in LOS pressure, which may be the basis of symptomatic GOR in pregnancy.