Parturition events and risk of urinary incontinence in later life.

Aims: To examine the association between specific events during vaginal deliveries and urinary incontinence later in life.

Methods: A retrospective cohort study of 1,521 middle-aged and older women with at least one vaginal delivery who were long-term members of an integrated health delivery system. Age, race/ethnicity, current incontinence status, medical, surgical history, pregnancy and parturition history, menopausal status, hormone replacement, health habits, and general health were obtained by questionnaire. Labor and delivery records, archived since 1948, were abstracted by professional medical record abstractors to obtain parturition events including induction, length of labor stages, type of anesthesia, episiotomy, instrumental delivery, and birth weight. The primary dependent variable was current weekly urinary incontinence (once per week or more often) versus urinary incontinence less than monthly (including no incontinence) in past 12 months. Associations of parturition events and later incontinence were assessed in multivariate analysis with logistic regression.

Results: The mean age of participants was 56 years. After adjustment for multiple risk factors, weekly urinary incontinence significantly associated with age at first birth (P = 0.036), greatest birth weight (P = 0.005), and ever having been induced for labor (OR = 1.51; 95%CI = 1.06-2.16, P = 0.02). Risk of incontinence increased from OR = 1.35 (95%CI = 0.92-1.97, P = 0.12) for women with one induction to OR = 2.67 (95%CI = 1.25-5.71, P = 0.01) for women with two or more inductions (P = 0.01 for trend). No other parturition factors were associated with incontinence.

Conclusions: Younger age at first birth, greatest birth weight, and induction of labor were associated with an increased risk of incontinence in later life.