Multiple hyperbaric exposures during pregnancy in sheep.

Eleven sheep were subjected to hyperbaric comparable to 165 feet of sea water 31 times between the one hundred twelfth and one hundred thirty-seventh days of pregnancy. During 13 dives the maternal and fetal circulations were monitored for bubble formation during decompression. Bubbles were detected by external doppler probes in eight of 12 ewes, but in none of the fetuses. Nine ewes were delivered of normal lambs at term. In one, twin fetuses died during an abnormal labor. The pregnancy of another was terminated by cesarean section after decompression to look for bubbles in the fetal circulation.