Objective: To investigate zidovudine prophylaxis with caesarean section to reduce mother-to-infant HIV transmission.
Interventions: Elective caesarean section before labour, usually at 36-38 weeks of gestation, plus a short oral course of zidovudine, normally starting at week 32, intravenous zidovudine before caesarean section and for 10 days for the neonate (the reduced Berlin regimen).
Results: Of 179 mother-infant pairs 104 received no antiretroviral prophylaxis or therapy (control group), 48 received the reduced Berlin prophylaxis regimen, 18 received combination therapy and nine received only part of the prophylaxis regimen. Of the antiretroviral group, 68 were delivered by elective caesarean section. The HIV transmission rate was zero in the antiretroviral group [95% confidence interval (CI) 0-4.7] and 12.6% (6.4-19.0) in the control group. The reduction in vertical transmission was 90% for the Berlin regimen, with an 80 and 70% reduction in risk associated with antiretroviral treatment and caesarean section, respectively. Maternal CD4 cell count but not viral load had some confounding effect on the reduction in risk attributed to caesarean section and the prophylactic regimen. Neonatal haematological abnormalities associated with antiretroviral intervention lasted for up to 7 weeks. Weight and length, although significantly lower at birth, were normal by 6-8 weeks.
Conclusion: A much reduced three-arm regimen of zidovudine prophylaxis in combination with caesarean section before labour is highly effective in reducing the risk of vertical HIV transmission and is safe for the infant.