Hypothetical role of prostaglandins in the onset of preterm labor after fetal surgery.

Preterm labor is one of the most important factors limiting the advancement of fetal surgery programs. While prostaglandins (PGs) have long been indicated as the key factor in the initiation of labor in humans, there is significant evidence showing that the chorionic membrane acts as a powerful barrier between the decidua/myometrium and amniotic PGs during normal pregnancy. After either open or endoscopic fetal surgery the imperfect, non-hermetical closure of the chorion permits leakage of PGs from the amnionic sac, allowing them to reach the decidua and myometrium. The surgical wound in the chorionic barrier could be the major factor involved in preterm labor and delivery after human fetal surgery.