Kenneth J Rothman

STUDY QUESTION: To what extent is male physical activity (PA) associated with fecundability (per-cycle probability of conception)? SUMMARY ANSWER: Preconception levels of vigorous, moderate, or total PA were not consistently associated wit…

STUDY QUESTION: To what extent are self-reported diagnoses of food allergies associated with fecundability, the per-cycle probability of conception? SUMMARY ANSWER: Fecundability was not appreciably associated with self-reported food aller…

STUDY QUESTION: To what extent is preconception maternal or paternal coronavirus disease 2019 (COVID-19) vaccination associated with miscarriage incidence? SUMMARY ANSWER: COVID-19 vaccination in either partner at any time before conceptio…

OBJECTIVES: To evaluate the association between preconception contraceptive use and miscarriage. DESIGN: Prospective cohort study. SETTING: Residents of the United States of America or Canada, recruited from 2013 until the end of 2022. P…

Few studies have evaluated the association between periodontitis and spontaneous abortion (SAB), and all had limitations. We used data from the Pregnancy Study Online (PRESTO), a prospective preconception cohort study of 3,444 pregnancy pla…

PURPOSE: To evaluate the relationships among history of asthma, asthma severity, and spontaneous abortion (SAB). METHODS: Pregnancy Study Online is a preconception cohort study of North American couples. During the preconception period, fe…

OBJECTIVE: To explore to what extent intrauterine device (IUD) expulsion is associated with demographic and clinical risk factors. METHODS: The APEX-IUD (Association of Perforation and Expulsion of IntraUterine Devices) study was a U.S. co…

BACKGROUND: Refusal to participate in studies related to sexual health can compromise the internal and external validity of findings. Research examining non-response to sexual health studies has primarily focused on predictors such as speci…

BACKGROUND: Migraine is common among females of reproductive age (estimated prevalence:17-24%) and may be associated with reproductive health through underlying central nervous system excitability, autoimmune conditions, and autonomic dysfu…

STUDY QUESTION: Do daughters of older mothers have lower fecundability? SUMMARY ANSWER: In this cohort study of North American pregnancy planners, there was virtually no association between maternal age ≥35 years and daughters' fecundabili…

OBJECTIVE: To evaluate the association between pregravid use of a variety of contraceptive methods and subsequent fecundability. DESIGN: Prospective cohort study. SETTING: Denmark and North America, 2007-19. PARTICIPANTS: 17 954 women wh…

The association between dietary fat and fertility is not well studied. We evaluated intakes of total fat, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, trans fatty acids (TFA), ω-3 fatty acids, and ω-6 fat…

BACKGROUND: The synthetic solvent tetrachloroethylene (PCE), commonly used in dry cleaning operations, is a human neurotoxicant and carcinogen. However, its effect on reproduction is poorly understood, as prior studies have been limited to …

BACKGROUND: Animal studies have shown that a high intake of galactose, a breakdown product of lactose, increases ovarian toxicity. Few epidemiologic studies, to our knowledge, have examined the association between dairy intake and fertility…

STUDY QUESTION: To what extent is preconception use of pain-relieving medication associated with female fecundability? SUMMARY ANSWER: Women who used naproxen or opioids had slightly lower fecundability than women who did not use any pain-…

PURPOSE: The aim of this study was to evaluate the association between menstrual cycle characteristics in early life and adulthood and fecundability. METHODS: Pregnancy Study Online (PRESTO) is an Internet-based preconception cohort study …