Gastric myoelectrical activity in the first trimester of pregnancy: a cutaneous electrogastrographic study.

Recently, it has been shown that changes in gastric electrical rhythm can be connected with clinical syndromes characterized by nausea and vomiting, among these the nausea of pregnancy. We studied gastric electrical activity during the first trimester of pregnancy in nine women with nausea and vomiting (study group) by means of cutaneous electrogastrography. Recordings were made before and after a standardized meal in the 6th-8th wk of gestation, and 2 months after voluntary interruption of pregnancy (VIP). The control group consisted of eight pregnant women without a history of nausea and vomiting. In the women in the study group there was more unstable cutaneous electrogastrographic (EGGc) activity and a reduced increase in postprandial power during pregnancy than after VIP, when a normal pattern with regular 3-cpm EGGc waves was reestablished. The coefficient of variation of gastric frequency during pregnancy was significantly higher than after VIP (p less than 0.01), whereas the postprandial to preprandial power ratio was lower (p less than 0.01). During the recording sessions, none of the subjects had clear episodes of tachygastria or bradygastria, and none of them had nausea, vomiting, or epigastric discomfort. Comparison of the EGGc data for the pregnant women in the study and control groups revealed a similar pattern of gastric electrical activity in the two, the only exception being the power ratio, which was lower in the study group (p less than 0.01). We conclude that pregnant women without symptoms of nausea and vomiting at the time of EGG recordings have normal 3-cpm myoelectrical activity, and that EGGc activity is more unstable and less responsive to the ingestion of food during pregnancy than after VIP. Furthermore, in pregnant women with a history of nausea and vomiting, EGGc activity is less responsive to the ingestion of food than it is in symptom-free pregnant women.