Offspring of women infected with varicella during pregnancy: a prospective study.

Despite the well-recognized association between maternal varicella infection and a specific pattern of malformation in the offspring referred to as fetal varicella syndrome, the full spectrum of this disorder as well as its frequency in the offspring of women infected with varicella during pregnancy is unknown. In order to resolve these issues, we have evaluated pregnancy outcome in 194 women who contacted us during pregnancy, soon after the onset of their infection: 132 (68%) during the 1st trimester and 171 (88%) prior to the onset of the 20th week, the most critical period relative to fetal susceptibility. Of those 171 women, there were 146 liveborn babies, 6 spontaneous abortions, 7 therapeutic abortions (one because of an anencephalic fetus), 2 stillborn infants, and nine pregnancies lost to follow-up. Of the 146 liveborn births, there were 2 with features consistent with the fetal varicella syndrome: one a child with mild cutaneous scars on her face, arms, and legs, Horner syndrome involving her left eye and a scar on her retina, leading to blindness in that eye; and the other, a child with horizontal nystagmus who is otherwise normal at 1 year of age. An additional four liveborn infants had a single major malformation which included unilateral microtia, bowel obstruction secondary to an ileal band, bilateral double ureters, and a thyroglossal duct cyst. This study suggests that prenatal varicella infection is associated with a wider spectrum of severity than has been previously appreciated and indicates that maternal varicella infection prior to the 20th week of pregnancy is associated with only a small risk for the developing fetus.