The risk of fetal varicella syndrome is maximum when the mother is infected between ________

The highest risk of fetal varicella syndrome is when the mother develops varicella between 13 to 20 weeks. It occurs in 2% of fetuses of mothers infected at this time. Congenital infections, paicularly after 20 weeks, are uncommon. However, if the fetus or neonate is exposed to active infection judt before or during delivery i.e., before maternal antibody has been formed, then there is a serious threat to newborns. No discrepancy between statements &;Varicella is most commonly contracted in first trimester&; and &;the risk of fetal varicella syndrome is highest between 13-20 weeks&; Ref: Williams Obsteics 25th edition Pgno: 1213