Congenital infection with human cytomegalovirus is a major cause of morbidity and mortality. A randomized controlled trial showed that high-dosage valacyclovir prevents cytomegalovirus disease in transplant recipients. Fetuses showing ultrasound features of infection are at high risk of being symptomatic at or before birth. In a pilot study, oral administration of high-dosage valacyclovir to mothers significantly decreased viral load and produced therapeutic concentrations in the blood of infected fetuses. A randomized controlled trial comparing prenatal treatment with valacyclovir against placebo in infected fetuses failed to recruit because women declined randomization. Randomized controlled trials in fetal medicine have often proven unacceptable by women who decline termination of pregnancy and are not prepared to resign themselves to the odds of the natural history of the disease. We evaluated the efficacy of oral valacyclovir, 8 g daily, for pregnant women carrying a symptomatic cytomegalovirus-infected fetus, targeting a high-risk group for developing both neurosensory and neurological impairment. We designed a multicenter, open-label, phase II study with 1 arm, using one of Simon's optimal 2-stage designs. Symptomatic fetuses were defined by the presence of measurable extracerebral or mild cerebral ultrasound symptoms. They were treated in utero from prenatal diagnosis at a median of 25.9 weeks' gestation until delivery or termination of pregnancy. Fetuses with severe brain anomalies on ultrasound were not included as were cases completely asymptomatic at presentation, because treatment was unlikely to modify either outcome. The primary endpoint was the proportion of asymptomatic neonates born to treated mothers. At the interim analysis, 8 of 11 women delivered an asymptomatic neonate (required: ≥7). In step 2, 32 additional cases were included for a total of 43; the final number of asymptomatic neonates was 34, more than the 31 required to indicate efficacy according to the Simon 2-stage design. They remained asymptomatic at 12 months. High-dosage valacyclovir given for a median of 89 days to pregnant women carrying a moderately infected fetus was efficient at giving birth to asymptomatic neonates. Fetal blood viral loads decreased and platelet counts increased, both significantly (P = .01 and P < .001, respectively), between treatment initiation and birth after treatment completion, regardless of duration of fetal infection. Compared with a historical cohort obtained by a metaanalysis of the literature, the use of valacyclovir (8 g daily) significantly increased the proportion of asymptomatic neonates from 43% without treatment to 82% with treatment. Although the pill burden was high (16 pills a day) adherence to treatment was >90%. Finally, valacyclovir at this high dosage was extremely well tolerated. Our results indicate that high-dosage valacyclovir given in pregnancy is effective for improving the outcome of moderately symptomatic infected fetuses. Although this study is not a randomized controlled trial, this is the first study reporting the efficacy of an antiviral drug to treat cytomegalovirus-infected fetuses. Moreover, this first study will allow new trials to be conducted, using valacyclovir as a baseline safe and effective treatment in pregnancy, to be compared to the new emerging and more potent anticytomegalovirus drugs that have not currently been tested in pregnancy.

Objective: To evaluate the relative contributions to the diagnosis of fetal brain abnormalities of targeted ultrasound examination and magnetic resonance imaging (MRI) in fetuses infected with cytomegalovirus (CMV).Methods: This was a retrospective analysis of targeted brain ultrasound examination and fetal brain MRI performed in fetuses diagnosed with CMV infection following proven maternal primary infection. The prenatal findings were compared with findings from postnatal transfontanellar ultrasound examination during the first week following delivery or from postmortem when the pregnancy was terminated.Results: Both targeted prenatal ultrasound and MRI were performed on 49 fetuses. Brain abnormalities were present in 15/49 (30.6%) cases at postnatal/post‐mortem follow‐up. Fetal cerebral abnormalities were observed in 19/49 (38.8%) cases by ultrasound and/or MRI. The most frequent cerebral lesions induced by CMV and seen on ultrasound and MRI, respectively, included ventricular dilatation in nine and five cases, subependymal cysts in two cases each, microcephaly in five and three cases and periventricular calcifications in five cases on ultrasound only. Termination of pregnancy was performed in 10/49 cases. Sensitivity, specificity and positive and negative predictive values for the presence of cerebral lesions were 88.9%, 93.3%, 88.9% and 93.3%, respectively, when both prenatal ultrasound and MRI findings were abnormal, 85.7%, 85.3%, 70.6% and 93.5%, respectively, for ultrasound alone, and 42.9%, 91.2%, 66.7% and 79.5%, respectively, for MRI alone. Prenatal ultrasound, MRI and postnatal or postmortem examinations were concordant with the presence of brain abnormalities in six cases; however, their conclusions were exactly concordant in only two (33.3%) of these cases. In cases without cerebral abnormality, the results of prenatal and postnatal/postmortem examinations were concordant in 28/34 cases.Conclusions: The addition of MRI to ultrasound increases the positive predictive value for the diagnosis of fetal brain abnormalities in fetuses with CMV. The two techniques appear to be complementary and should not be mutually exclusive in high‐risk fetuses. Their high predictive value for the presence or absence of cerebral lesions provides a useful tool for appropriate counseling since current evaluation of the prognosis is based mainly on the presence of fetal brain lesions. The lack of concordance between ultrasound and MRI should stimulate standardization of the interpretation of both ultrasound and MRI prospectively. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.

Objectives To estimate the rates of maternal-fetal transmission of Zika virus, adverse fetal/neonatal outcomes, and subsequent rates of asymptomatic/symptomatic congenital Zika virus infections up to the first week of life. Design Cohort study with prospective data collection and subsequent review of fetal/neonatal outcomes. Settings Referral centre for prenatal diagnosis of the French Guiana Western Hospital. Participants Pregnant women at any stage of pregnancy with a laboratory confirmed symptomatic or asymptomatic Zika virus infection during the epidemic period in western French Guiana. The cohort enrolled 300 participants and prospectively followed their 305 fetuses/newborns. Main outcome measures Rate of maternal-fetal transmission of Zika virus (amniotic fluid, fetal and neonatal blood, urine, cerebrospinal fluid, and placentas); clinical, biological, and radiological outcomes (blindly reviewed); and adverse outcomes defined as moderate signs potentially related to congenital Zika syndrome (CZS), severe complications compatible with CZS, or fetal loss. Associations between a laboratory confirmed congenital Zika virus infection and adverse fetal/neonatal outcomes were evaluated. Results Maternal-fetal transmission was documented in 26% (76/291) of fetuses/newborns with complete data. Among the Zika virus positive fetuses/newborns, 45% (34/76) presented with no signs/complications at birth, 20% (15/76) with moderate signs potentially related to CZS, 21% (16/76) with severe complications compatible with CZS, and 14% (11/76) with fetal loss. Compared with the Zika virus positive fetuses/neonates, those that were identified as negative for Zika virus (215/291) were less likely to present with severe complications (5%; 10/215) or fetal loss (0.5%; 1/215; relative risk 6.9, 95% confidence interval 3.6 to 13.3). Association between a positive Zika virus test and any adverse fetal/neonatal outcome was also significant (relative risk 4.4, 2.9 to 6.6). The population attributable fraction estimates that a confirmed congenital Zika virus infection contributes to 47% of adverse outcomes and 61% of severe adverse outcomes observed. Conclusion In cases of a known maternal Zika virus infection, approximately a quarter of fetuses will become congenitally infected, of which a third will have severe complications at birth or fetal loss. The burden of CZS might be lower than initially described in South America and may not differ from other congenital infections.