Condom use as a function of number of coital events in new relationships

STUDY OBJECTIVE: To assess condom use as a function of number of coital events in newly formed sexual relationships. METHODS: Participants who reported at least one new partner during the 12-week study interval (n = 115; ages 18-29 years; 48% women; 90% African American) completed weekly sexually transmitted infections testing and 3 times daily electronic diary collection assessing individual and partner-specific affect, daily activities, sexual behavior, and condom use. We analyzed event-level condom use percentage and participant-level behavior response effects. generalized additive mixed models were used to estimate condom use probability accounting for within-partner and within-participant correlations via random effects. RESULTS: The average condom use probability at the first coital event in new relationships was 55% for men and 36% for women. Analyses showed that smooth shapes of estimated condom use probabilities were similar for both sexes and were fitted using generalized additive mixed models. Relatively higher condom use percentage was followed by a sharp decline during the first 9 coital events decreasing to 16% for men and 8% for women. More rapid decline in condom use among women was highly associated with higher levels of relationship and sexual satisfaction. CONCLUSIONS: The likelihood of condom use declines sharply for both men and women after the early accrual experience with a partner. Relationship and sexual satisfaction also influence declines in condom use, especially among women