Interference with neural crest migration by maternal hyperthermia as a cause of embryonic death due to heart failure.

Maternal hyperthermia has been demonstrated to be a teratogen in every animal species studied, and a minimum core temperature rise of 2.5 degrees C can produce a number of developmental defects. However, numerous embryos fail to survive to term. In the guinea-pig, heating the embryos prior to neural tube closure induces significant neural tube defects, but all embryos die within 20 days of heating. A number have aberrant cardiac development and many show spectacular pericardial effusions and congestion in the peripheral circulation. We suggest that maternal hyperthermia has interfered with neural crest migration which is a major component in the induction of these changes.