Antiretroviral Therapy Use During Pregnancy and the Risk of Small for Gestational Age Birth in a Medicaid Population

Abstract

Background: Several studies have assessed the association between antiretroviral (ARV) therapy use during pregnancy and small for gestational age (SGA), but the evidence remains incompletely elucidated.

Methods: We linked data from Tennessee Medicaid files and vital records to evaluate pregnancies among human immunodeficiency virus (HIV)-infected women who delivered between 1994 and 2009. Maternal HIV status was defined based on diagnosis codes, ARV prescriptions and laboratory codes for CD4 count or HIV RNA assays. ARV use was identified from pharmacy claims. Risk of SGA (defined as birth weight below the 10th percentile for gestational age) and preterm birth was evaluated using logistic regression models.

Results: Four hundred and seventy-seven HIV-infected pregnant women contributing 604 singleton pregnancies were identified; 156 (26%) delivered SGA infants. ARV use during pregnancy was not associated with SGA [adjusted odds ratio: 0.93; 95% confidence interval (CI): 0.56-1.56] or preterm birth (adjusted odds ratio: 0.74; 95% CI: 0.42-1.32). Exposure to a protease inhibitor during the first trimester was associated with a lower risk of SGA (odds ratio: 0.54; 95% CI: 0.29-1.01) compared with non-exposure to a protease inhibitor throughout pregnancy.

Conclusions: We observed no evidence of an association between ARV exposure during pregnancy and SGA delivery in this Medicaid cohort of HIV-infected women.

Figure 1. Cohort structure

HIV = human immunodeficiency virus; LMP = last menstrual period; ARV = antiretroviral ^aThese are pregnancies that were either (1) not enrolled with drug coverage from LMP-30 through delivery (N=364) or (2) had an HIV claim only prior to LMP-365 (N = 639) or (3) had an HIV claim only prior to LMP-365 and after delivery (N=26) ^bIncludes women with the following indication(s) for HIV: (a) one (or more) inpatient diagnoses (prior to the birth hospitalization), or (b) two (or more) outpatient diagnoses separated by at least 30 days, or (c) two (or more) prescriptions for ARVs on different dates, or (d) any combination of two indications (one or more of each of the following indications – birth hospitalization diagnosis plus outpatient diagnosis, or birth hospitalization diagnosis plus prescription, or birth hospitalization diagnosis plus procedure, or outpatient diagnosis plus prescription, or outpatient diagnosis plus procedure, or prescription plus procedure)

Figure 2. Trends over time - Late access to prenatal care and SGA among HIV-infected pregnant women in Tennessee Medicaid: 1994 – 2009

SGA: small-for-gestational age (defined as birthweight weight below the 10th percentile for the gestational age). The number of pregnancies for each birth cohort is as follows: <2002 = 154; 2002 – 2004 = 198; 2005 – 2007 = 150; 2008 – 2009 = 102 Note: Late access to prenatal care was defined as starting prenatal care in the 3rd trimester or not having any prenatal care throughout pregnancy. A slight increase in SGA births among those with late access to prenatal care over time was observed (<2002, 5.8%; 2002 – 2004, 7.8%; 2005 – 2007, 9.7%; 2008 – 2009, 12%)