Incidence of pregnancy after initiation of antiretroviral therapy in South Africa: a retrospective clinical cohort analysis.
BACKGROUND
Little is known about rates of incident pregnancy among HIV-positive women initiating highly active antiretroviral therapy (HAART).


METHODS
We conducted a retrospective clinical cohort study among therapy-naïve women ages 18-45 initiating HAART between 1 April 2004 and 30 September 2009 at an adult HAART clinic in Johannesburg, South Africa. We used Poisson regression to characterize rates and rate ratios of pregnancy.


RESULTS
We evaluated 5,996 women who experienced 727 pregnancies during 14,095 person-years at risk. The overall rate of pregnancy was 5.2 per 100 person-years (95% confidence limits [CL] 4.8, 5.5). By six years, cumulative incidence of first pregnancy was 22.9% (95% CL 20.6%, 25.4%); among women ages 18-25 at HAART initiation, cumulative incidence was 52.2% (95% CL 35.0%, 71.8%). The strongest predictor of incidence of pregnancy was age, with women 18-25 having 13.2 times the rate of pregnancy of women ages 40-45 in adjusted analysis. CD4 counts below 100 and worse adherence to HAART were associated with lower rates of incident pregnancy.


CONCLUSIONS
Women experience high rates of incident pregnancy after HAART initiation. Understanding which women are most likely to experience pregnancy will help planning and future efforts to understand the implications of pregnancy for response to HAART.
Department of Obstetrics and Gynecology and Duke Global Health Institute, Duke University, Durham, NC 27710, USA. daniel.westreich@duke.edu
Daniel
D
Westreich
Mhairi
M
Maskew
Dennis
D
Rubel
Pippa
P
MacDonald
Imogen
I
Jaffray
Pappie
P
Majuba
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008875:Middle Aged; D011247:Pregnancy; D018873:Pregnancy Rate; D012044:Regression Analysis; D012189:Retrospective Studies; D013019:South Africa; D055815:Young Adult