Frequency of congenital varicella syndrome in a prospective cohort of 347 pregnant women.

OBJECTIVE: To estimate the rate of congenital varicella zoster virus syndrome in neonates born to women developing varicella zoster virus infections during pregnancy.

METHODS: Pregnant women with clinical varicella zoster virus infection were enrolled at ten perinatal centers. Maternal and fetal immunoglobulin (Ig) G and IgM by fluorescent antibody confirmed 74.3% of cases. Specialists examined neonates at 0-6 months, 7-18 months, and 19-30 months after delivery to detect abnormalities of their eyes, hearing, and physical and developmental features. A hierarchical set of criteria was used to define congenital varicella syndrome. A jury of four investigators assigned the classification of all findings.

RESULTS: In 362 women enrolled from 1993 to 1996, 15 had herpes zoster, and 347 had primary varicella zoster virus infection. Varicella zoster virus affected 140 women (38.7%) in the first trimester, 122 (33.7%) in the second trimester, and 100 (27.6%) in the third trimester. Five twin pairs were included. Only one case (0.4%) of definite congenital varicella syndrome was found, a 3360-g female infant having a left retinal macular lesion with typical skin scars after maternal varicella at 24 weeks. The maternal blood sample at birth was negative for IgG antibodies to toxoplasmosis and cytomegalovirus. Two cases involved fetal death at 20 weeks and fetal hydrops at 17 weeks after maternal varicella at 11 and 5 weeks, respectively. We found no cases of limb hypoplasia, microcephalus, or cataract.

CONCLUSION: The frequency of congenital varicella syndrome is very low (0.4%) in a prospectively studied cohort. Eye examinations of exposed infants had a low yield.