From a University of Pittsburgh School of Medicine Press Release about findings being presented at the International Congress of Neuroendocrinology June 19-22, 2006:

Stressful or traumatic events experienced during pregnancy can have long-lasting effects on the fetus, yet these effects may not become apparent until many years later, according to a study suggesting that girls born of such pregnancies may be at greater risk for developing a painful muscle condition called fibromyalgia as adults.

The details sound very much like recent findings regarding abnormalities in reactions to stressors in chronic fatique sufferers. That could lend credence to those who believe fibromyalgia and chronic fatigue syndrome are related conditions.