HIV in Pregnancy

The management of HIV infection during pregnancy is a significant public health and clinical success story, given the dramatic reduction in mother-to-child transmission risk.

This has been achieved through full antenatal HIV screening, effective antiretroviral therapy, and appropriately individualised delivery and infant feeding planning.

Transmission risk has fallen from historically substantial rates (in the absence of any intervention) to a very low, near-negligible rate with fully optimised, contemporary management.

This underscores the substantial value of universal antenatal HIV screening and full, structured multidisciplinary care for HIV-positive pregnant women.

Pathophysiology of mother-to-child transmission

• Mother-to-child transmission of HIV can occur during pregnancy (in utero transmission), during labour and delivery, or postnatally through breastfeeding.
• Labour and delivery is the predominant route in the absence of effective intervention, reflecting exposure to maternal blood and genital secretions.
• The relative contribution of each route, and the relevance of the preventive interventions targeting each, informs the multi-component approach to transmission risk reduction.
• The single most important determinant of transmission risk is maternal plasma HIV viral load at the time of delivery.
• Women who achieve and maintain an undetectable viral load through effective antiretroviral therapy have a very low, near-negligible transmission risk. Effective antiretroviral treatment throughout pregnancy is therefore the primary transmission risk reduction strategy.
• Additional factors influencing transmission risk include mode of delivery (with elective caesarean delivery specifically indicated for women with a detectable viral load close to delivery), duration of ruptured membranes, and infant feeding method.
• Breastfeeding carries an additional, incremental transmission risk even in women on effective antiretroviral therapy. This is relevant to infant feeding counselling and decision-making.

• The great majority of HIV-positive pregnant women are identified through universal, routine antenatal HIV screening, rather than through symptomatic presentation. This reflects the frequently asymptomatic nature of chronic HIV infection, particularly in women already established on effective treatment before conception.
• Pregnancy itself does not appear to substantially accelerate HIV disease progression in women with well controlled infection.
• HIV infection, when well managed with effective antiretroviral therapy, does not appear to substantially increase the risk of most pregnancy-specific complications.
• Careful, full obstetric care remains essential, given the potential for various antiretroviral medications to carry their own specific considerations during pregnancy.
• Newly diagnosed HIV infection during pregnancy, identified through routine antenatal screening in a woman not previously aware of her HIV status, is an important, common scenario. It requires prompt, sensitive communication of this significant diagnosis together with immediate linkage to specialist HIV and obstetric care.
• Infants born to HIV-positive mothers require structured postnatal management and testing, given the inherent uncertainty regarding their own HIV status at birth despite optimal maternal management.
• Definitive exclusion of infection requires a structured testing protocol extending over the first months of life.

• Universal antenatal HIV screening, offered to all pregnant women as a routine component of booking blood tests, is the essential foundation for identifying HIV infection in pregnancy. A substantial proportion of maternal HIV infection is identified through this route rather than through pre-existing, known diagnosis.
• Baseline assessment following diagnosis or confirmation of known HIV status guides treatment planning. It includes CD4 count, viral load, and antiretroviral resistance testing where relevant, together with assessment for any coexisting opportunistic infection or other relevant HIV-associated condition.
• Regular monitoring of maternal viral load throughout pregnancy is an essential, ongoing component of antenatal HIV care. Pay particular attention to achieving and confirming an undetectable or very low viral load approaching the time of delivery, which directly informs delivery mode planning.

• Combination antiretroviral therapy is the cornerstone of management. Commence it as early as possible in pregnancy, or continue it where the woman is already established on effective treatment before conception, with careful review of the regimen to confirm ongoing appropriateness and safety during pregnancy.
• Regimen selection is guided by current treatment guidelines and individual patient factors. The aim is a fully suppressed, undetectable viral load well before the anticipated delivery.
• Mode of delivery planning is guided by maternal viral load status approaching term.
• Vaginal delivery is generally appropriate and recommended for women with a confirmed, sustained undetectable viral load.
• Elective caesarean delivery is recommended for women with a detectable viral load (generally above a defined threshold according to current guidelines) close to the time of delivery. This avoids the additional transmission risk associated with vaginal delivery and prolonged labour exposure in this higher-risk context.
• Intrapartum considerations include avoidance of unnecessary invasive procedures carrying potential for increased maternal-fetal blood exposure. Fetal scalp electrode placement and instrumental delivery are avoided where possible, particularly in women with any degree of detectable viral load.
• In some clinical circumstances, according to viral load status, intravenous intrapartum antiretroviral administration is given.
• Infant feeding counselling requires careful, individualised, and culturally sensitive discussion.
• Formula feeding carries zero risk of postnatal transmission and is generally recommended in well-resourced settings with reliable access to safe formula feeding.
• Breastfeeding carries some residual, additional transmission risk even with maternal viral suppression. It may be an appropriate, supported option in specific circumstances, including limited access to safe formula feeding alternatives, or according to the mother's informed preference following counselling regarding the residual risk.
• The approach and available guidance vary according to local resource context and current clinical guidelines.
• Neonatal postnatal management comprises postnatal antiretroviral prophylaxis to the infant. The regimen and duration are individualised according to the assessed level of maternal transmission risk.
• Regimens range from a shorter, single-agent regimen for infants at standard risk to a more intensive, combination regimen for infants at higher assessed transmission risk.
• A structured schedule of infant HIV testing extends over the first months of life, to confirm or exclude infant infection.
• Standard antibody-based testing has specific limitations in this age group, because of passively transferred maternal antibody. Definitive diagnosis therefore relies on virological testing methods during early infancy.
• Ongoing multidisciplinary care throughout pregnancy, delivery, and the postnatal period incorporates specialist HIV, obstetric, and paediatric expertise.
• Provide psychosocial support addressing the sensitive implications of this diagnosis. Communicate clearly and in a structured way the excellent, near-negligible transmission risk achievable with fully optimised contemporary management.