Tohoku J. Exp. Med., 2006, 208(1)

Appearance of Abnormal Electrocorticogram Patterns during Umbilical Cord Compression in Sheep Fetus

TAKESHI TAKAHASHI, JUNICHI SUGAWARA, HIROSHI CHISAKA, NORIAKI IMAI, MASATOSHI SAITO, TAKASHI MURAKAMI, YOSHITAKA KIMURA and KUNIHIRO OKAMURA

Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan

A frequent cause of fetal acidemia, which sometimes results in hypoxic-ischemic encephalopathy, is umbilical cord compression associated with uterine contraction. Using a sheep model of fetal acidemia, we examined the changes in electrocorticogram (ECoG), carotid artery blood flow, arterial blood pressure and fetal heart rate during cord compression. A characteristic burst of ECoG spikes emerged during cord compression at fetal arterial pH 7.18 even before the pH went down to severe fetal acidemia (less than 7.10). The administration of a neuromuscular blocking agent to the fetus did not abolish the appearance of the spikes. These results suggest that cord compression may cause abnormal brain excitement even in the absence of severe fetal acidemia and that this abnormal excitement can lead to fetal brain dysfunction, if cord compression is repeated or prolonged.

keywords —— fetal heart rate; cord compression; fetal electrocorticogram; fetal acidemia

© 2006 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2006, 208, 9-17

Received August 3, 2005; revision accepted for publication October 8, 2005.
Correspondence: Dr. Kunihiro Okamura, Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, 1-1 Seiryomachi, Aoba-ku, Sendai 980-8575, Japan.

e-mail: okamura@mail.tains.tohoku.ac.jp