Changes in behavior with increasing pregnancy attempt time: a prospective cohort study.

BACKGROUND The extent to which couples change their behaviors with increasing pregnancy attempt time is not well documented. METHODS We examined change in selected behaviors over pregnancy attempt time in a North American preconception cohort study. Eligible females were aged 21-45 years and not using fertility treatment. Participants completed baseline and bimonthly follow-up questionnaires for up to 12 months or until pregnancy. RESULTS Among 3,339 females attempting pregnancy for 0-1 cycles at enrollment, 250 contributed 12 months of follow-up without conceiving. Comparing behaviors at 12 months versus baseline, weighted for loss-to-follow-up, we observed small-to-moderate reductions in mean caffeine intake (-19.5 mg/day, CI: -32.7, -6.37), alcohol intake (-0.85 drinks/week, CI: -1.28, -0.43), marijuana use (-3.89 percentage points, CI: -7.33, 0.46), and vigorous exercise (-0.68 hours/week, CI: -1.05, -0.31), and a large increase in activities to improve conception chances (e.g., ovulation testing) (21.7 percentage points, CI: 14.8, 28.6). There was little change in mean cigarette smoking (-0.27 percentage points, CI: -1.58, 1.04), perceived stress scale score (-0.04 units, CI: -0.77, 0.69), or other factors (e.g., sugar-sweetened soda intake, moderate exercise, intercourse frequency, and multivitamin use), but some heterogeneity within subgroups (e.g., 31% increased and 32% decreased their perceived stress scores by ≥2 units; 14% reduced their smoking but none increased their smoking by ≥5 cigarettes/day). CONCLUSIONS While many behaviors changed with increasing pregnancy attempt time, mean changes tended to be modest for most variables. The largest differences were observed for use of caffeine, alcohol, and marijuana, and methods to improve conception chances.