EP04.06: Effectiveness and safety of valacyclovir in primary CMV infection during pregnancy

To evaluate the efficacy and safety of valacyclovir in preventing CMV transmission after maternal primary infection, which is the primary cause of non-genetic hearing and neurological defects. This was a retrospective case-control study with primary CMV diagnosed prior the periconceptional period/first trimester between 2017 and 2022. The following data were examined in all patients: CMV IgG/IgM, IgG avidity, CMV DNA in blood and urine, risk factors and gestational age at seroconversion. Amniocentesis was recommended after 6/8 weeks from infection to quantify CMV DNA via PCR. All fetuses were screened with ultrasound exams, fetal echocardiography and fetal MRI performed with T2 HASTE, TRUEFISP static and dynamic, T1 VIBE, T1 flash 2D sequences and diffusion technique. Furthermore, inherent data of infants were also collected, such as presence of virus in blood and urine or anomalies related to CMV. Data were analysed using IBM SPSS. 80 pregnant women with primary CMV infection were included and divided in two groups: group 1 (43 patients) who were administered valacyclovir (8000mg daily) during pregnancy and group 2 (37 patients) who did not receive it. The presence of CMV DNA in the amniotic fluid was in the 7.9% and in the 34.5% of cases in group 1 and group 2 (p = 0.006). Ultrasound anomalies were found in the 37.2% of patients of group 1 and in 54% of group 2 (p = 0.13) while anomalies on fetal echocardiography were found in 6.2% of group 1 and 27.8% of group 2 (p = 0.03). Findings of encephalic abnormalities were present on fetal MRI in 9.4% of cases in group 1 and 19.2% in group 2 (p = 0.28). Congenital infection in infants, diagnosed by detection of CMV DNA in urine, was present in 19.3% and 30% of cases in groups 1 and 2 (p = 0.33). Finally, none of the infants in group 1 had anomalies associated with congenital CMV infection, and no adverse effects were reported with valacyclovir. This study confirms the efficacy and safety of valacyclovir as secondary prevention of congenital CMV infection.