Intermittent breathing before death in fetal lambs.

The presence of fetal breathing, even if episodic in character, may not indicate fetal well being. In a study of fetal lambs with long-term implantation of catheters and electrodes, five of six lambs which died before the onset of labor had terminal episodes of continuous breathing, preceded by 4 1/4 to 45 1/2 hours of abnormal intermittent breathing. Intermittent bursts of slow gasping or rapid breathing at exceptionally regular rates and depths were observed. The rapid pattern was associated with epileptiform seizures in two of three lambs. In all lambs, the abnormal intermittent breathing was preceded by prolonged apnea.