Objectives: Fertility intentions and contraceptive use are often not assessed in the context of clinical HIV care, representing a possible programming gap if women's family planning needs change over time. We aimed to identify longitudinal patterns of unmet need for contraception over a 12-month period among women living with HIV taking antiretroviral therapy (ART). Study design: 850 non-pregnant, HIV-positive women aged 18-35 on or initiating ART in Johannesburg, South Africa, were enrolled into a prospective cohort study in 2009-2010. Fertility intentions and contraceptive use were assessed during routine HIV care visits via an interviewer-administered questionnaire, and women were referred for on-site contraceptive counseling. We used group-based trajectory modeling to identify patterns of unmet need for contraception over 12 months, first in the entire population and then in a subset of recent ART initiators. Results: In the full population we identified four patterns of unmet need for contraception over one year. Half of the enrolled women were predicted to have a consistently high probability of unmet need, 22.9% a consistently low probability, 16.7% a decreasing probability, and 10.4% an increasing probability over time. Contraceptive method discontinuation and rapidly changing fertility intentions were the primary drivers of changing (increasing or decreasing) unmet need over follow-up. Results were similar in recent ART initiators. Conclusions: Half of women were estimated to have a high probability of unmet need that persisted over time, and more than a quarter were estimated to experience patterns of changing unmet need over 12 months. Family planning needs should be assessed more regularly in HIV-positive women to prevent unintended pregnancies and support safer conception among women trying to conceive
