First episode of genital herpes simplex virus infection in the third trimester of Pregnancy; diagnostic limitations and effects on mode of delivery: a case study

Abstract

BACKGROUND: Risk of herpes simplex viral (HSV) transmission to the baby during vaginal delivery following maternal primary genital herpes in the third trimester is 41%. Caesarean section is recommended in such instances to minimize the risk of neonatal herpes.DNA-PCR is the gold standard of diagnosis of HSV infection. Crossreactivity of HSV1 and HSV2 IgM, variable IgM response in relation to time make these tests less useful. Furthermore, raised IgM may not always indicate primary infection. DNA-PCR does not differentiate primary infection from a recurrence which has lower risk of neonatal herpes (0- 3%). IgG has a lower positive predictive value in low prevalence settings. CASE: A 19-year-old primigravida at 36 weeks presented with four days’ history of dysuria, multiple painful superficial genital ulcerson both labia with painful bilateral inguinal nodes. Neither she nor her partner had genital or oral lesions before. Syphilis serology, dark ground examination and HIV antibody test were negative whereas Tzanck smear was positive. Clinical diagnosis of primary HSV infection was made and she was treated with acyclovir which was continued until five days after delivery. Two weeks later, she was positive for HSV1+HSV2 IgM antibody ELISA, and negative for type common IgG. Elective LSCS resulted in a healthy baby weighing 3.02kg. Serology four days later had a slightly higher IgG index than previous assay. CONCLUSION: High risk of neonatal herpes following primary genital herpes during third trimester, inability to differentiate primary infection from recurrence by available investigations, and practical difficulties of performing these investigations, necessitate management decisions to be based on clinical diagnosis in resource limited settings.