Impact of maternal anti retroviral drugs during pregnancy on risk of preterm birth and low birth weight.
Introduction· HIV infection is a leading medical complication of pregnancy in most sub-Saharan African countries including Nigeria. Strategies involving antiretroviral medication and good obstetric practice have greatly reduced maternal deaths and vertical transmission of HIV. However, antiretroviral therapy could also have adverse effects on the pregnant woman or developing fetus e.g. preterm delivery and low birth weight. Preterm birth and low birth weight contribute significantly to perinatal morbidity and mortality. This review examined the impact of HAART on preterm birth and low birth weight.
Methodology· The authors reviewed literature using the search tenns of HIV, preterm birth, low birth weight, antiretroviral. Cross-sectional, observational and randomized controlled studies obtained from the commonly used medical databases, published between 1994 and 2013 were reviewed.
Results· The results were conflicting with some studies demonstrating increased risk of prematurity with anti-retrovirals. Others demonstrated no effect on risk of prematurity while others demonstrated a protective effect of these drugs. Similarly, studies that explored the association between duration of therapy and prematurity were conflicting. While some failed to detect a significantly increased risk of prematurity with longer duration of therapy following early exposure (compared with following initiation at 13-26 weeks gestation), others noted that starting PI-based HAART before pregnancy or in the first trimester was associated with higher risk of preterm delivery. Differences in population characteristics, indication for therapy. data collcction or analytical approachcs have been suggested as possible reasons for these discrepant findings. A reason proffered for the association of pretenn births and antiretrovirals is the Th2 to Th1 eytokine shift associated with HAART administration. Successful pregnancies are characterized by a Th1 to Th2 cytokine shift. Other associated factors were immunosuppression, multiple pregnancies and other psychosocial factors e.g. illicit drug use. Some studies, after standardizing for gestational age demonstrated that HAART exposed infants were significantly lighter than those exposed to mono or dual therapy. Others did not support an association between receipt of HAART during pregnancy and an increased risk of LBW. Other factors associated with low birth weight include immuno-supprcssion (CD4 < 200 cells/ml) and the HIV status of the HIV exposed infant.
Conclusion· With an increasing number of women on HAART at conception, it is reassuring that the strong benefits of prevention of MTCT are not outweighed by risks attributable to HAART. However, monitoring adverse pregnancy and perinatal outcomes should remain a priority and further research into the mechanisms leading to preterm birth and or LBW in HIV positive women needed.