Increased fetal nuchal translucency thickness at 10–14 weeks: is screening for maternal–fetal infection necessary?

Objective To investigate the relation between increased fetal nuchal translucency thickness at 10–14 weeks of gestation and maternal–fetal infection. Design Prospective study. Setting Harris Birthright Research Centre for Fetal Medicine. Population Four hundred and twenty-six chromosomally normal pregnancies with increased fetal nuchal translucency thickness at 10–14 weeks of gestation and 63 with ‘unexplained’ second or third trimester fetal nuchal oedema or hydrops. Methods Maternal serum infection screening and investigations for fetal infection in those with evidence of recent maternal infection. Main outcome measures Maternal and fetal infection. Results Evidence of recent maternal infection was present in six of the 426 pregnancies (1.4%) with increased fetal nuchal translucency thickness at 10–14 weeks, but in all cases a healthy infant was born with no evidence of infection. In contrast,‘unexplained’ second or third-trimester fetal hydrops was associated with maternal infection in six of the pregnancies (9.5%) and in all cases there was evidence of fetal infection. Conclusions Maternal–fetal infection is one of the causes of second or third trimester nuchal oedema or fetal hydrops. In contrast, the presence of increased nuchal translucency in the first trimester is not a marker of either maternal or fetal infection.