Characteristics associated with sex after periods of abstinence among sexually experienced young women.

CONTEXT Adolescent pregnancy prevention is difficult because adolescent sex is intermittent. Understanding why sexually experienced adolescents have sex after a period of abstinence will help clinicians to tailor counseling. METHODS For up to 4.5 years between 1999 and 2006, a sample of 354 adolescent women recruited at urban primary care clinics were interviewed and tested for STDs every three months, and were asked to complete three months of daily diaries twice a year. Survival analyses were used to estimate associations between intrapersonal, relationship and STD-related characteristics and the risk of ending an abstinence period with sex. RESULTS Participants reported 9,236 abstinence periods, which averaged 31 days. The risk that an abstinence period ended with sex increased steeply for periods of fewer than 17 days (short), rose less steeply for 17-39-day (intermediate) periods and was fairly steady for longer periods. For short periods, the risk increased with age, sexual interest, positive mood, partner support, relationship quality and history of STD diagnosis more than three months ago (hazard ratios, 1.02-1.2); it decreased as negative mood increased (0.98) and was reduced among adolescents with a recent STD diagnosis (0.9). For intermediate periods, the association with a recent STD diagnosis became positive (1.4). For long periods, sex was associated only with age, sexual interest and relationship quality. CONCLUSIONS To provide targeted and timely sexual health counseling, clinicians may want to ask adolescents not only whether they are sexually active but also when they last had sex.