Fetal heart rate pattern before, during and after amniotomy.

This prospective study concerned the immediate possible effects of low amniotomy on the fetal heart rate pattern of 32 normal term subjects. Artificial membrane rupture was performed early in labour in 16 gravidas and to induce labor in the others. In only 1 fetus was no specific alteration of the heart rate pattern recorded. The type and incidence of fetal heart rate pattern alterations observed during and within 1 h after low amniotomy were comparable in laboring and induced gravidas. The most frequently observed patterns were short-lived FHR acceleration and increased band-width. Short-lived bradycardia was recorded in only 4 patients after amniotomy. The majority of the alterations observed were not indicative of fetal distress as a direct result of artificial membrane rupture.