Smoking, Sex Hormones, and Pregnancy

The sample population will consist of oral contraceptive users, both "low" and "high" dose levels of exogenous progesterone with a consistent dose of exogenous estrogen. Participants will complete data collection procedures including providing saliva (cortisol to measure stress), urine (cotinine and 3-Hydroxycotinine to measure nicotine exposure), and blood (progesterone, allopregnanolone, and estradiol) samples, as well as ecological momentary assessments (EMA) daily for seven-days. Participants will also complete a 3-hour smoking topography lab session after overnight abstinence and a 4.5-hour nicotine nasal spray lab session after a 14-hour abstinence. These sessions will contain a nicotine challenge via smoking a cigarette or nasal spray with timed-series physiological, subjective, and behavioral responses.