Vaginal birth is now routinely recommended for women on ART with undetectable viral load at the time of delivery.
In high-income countries, C-section is still recommended when viral load is not undetectable or if there are complications that require C-section.
Caesarean involves surgery that cuts the abdominal wall to remove the infant from the uterus.
Before modern ART was available, planned caesarean section significantly reduced vertical transmission compared with vaginal birth. But there is no extra benefit if a mother is taking ART and has an undetectable viral load.
With an undetectable viral load on ART the risk of vertical transmission is close to zero with either a vaginal or casarean delivery.
A mother might sometimes need one for another reason.
Last updated: 1 January 2016.