Introduction: Half of pregnancies in the United States are unintended. We examine a novel risk factor for unintended pregnancies, impulsivity. We hypothesize that women with higher nonplanning impulsivity will be more likely to have an unplanned pregnancy.

Methods: The parent study was a prospective cohort study of 125 pregnant women examining the association between impulsivity and weight gain during pregnancy. At an in-person study visit, women completed self-report measures via a secure web form. The 15-item Barratt Impulsiveness Scale (BIS-15) measures impulsivity using subjective statements about the respondent’s behavior with 4 response options: rarely/never, occasionally, often, and almost always/always. Three subscales with 5 questions each measure attention, motor, and nonplanning impulsivity. We categorized women as being less impulsive (subscale score of 5-10) versus more impulsive (11-20). We chose this cutoff as a score of 10 indicates responses of “never/rarely” or “occasionally”, representing lower impulsivity. Pregnancy intention was measured by asking women “When you got pregnant, were you trying to get pregnant?” (yes or no).

Results: 34% reported that the current pregnancy was unplanned. 10% of women had high motor impulsivity, 21% high attention impulsivity, and 32% high nonplanning impulsivity. Women who were aged 18-24, obese, less educated, not married, of a lower socioeconomic status, and multigravid were more likely to have higher nonplanning impulsivity. 51% with high nonplanning impulsivity reported unplanned pregnancy compared to 25% (low nonplanning impulsivity). Women with high nonplanning impulsivity had 3.53 times the odds of unplanned pregnancy compared to women with low nonplanning impulsivity (adjusted for other 2 subscales and confounders; 95% CI: 1.23-10.14). Neither motor nor attention impulsivity was associated with pregnancy intention.

Conclusions: Women with higher levels of nonplanning impulsivity are at higher risk of having unplanned pregnancies. The 5-item nonplanning subscale of the BIS-15 may help to identify women with high nonplanning impulsivity clinically; women could complete this brief measure prior to office visits, and these scores could direct contraception counseling. Contraception that requires little maintenance and no decision-making at the time of sexual encounters, such as long-acting reversible contraceptives (LARCs), may potentially lower unplanned pregnancy rates among more impulsive women. Further research should focus on creating a framework to identify these women, implementing a screening tool in the clinical setting, and to explore whether increasing LARC use in this population can lower unplanned pregnancy rates.