Incontinence and pelvic organ prolapse in parous/nulliparous pairs of identical twins.

Aim: To evaluate the role of vaginal delivery in the development of urinary incontinence and pelvic organ prolapse in four sets of identical twins.

Methods: Four sets of identical twins were identified from 101 pairs of parous/nulliparous postmenopausal sister pairs, who completed a comprehensive questionnaire, and underwent clinical evaluation of urinary incontinence and pelvic organ prolapse as part of a study. Findings of identical twin sisters were compared to each other.

Results: Ages ranged from 52 to 56 years; the parous sister in each pair had two vaginal deliveries. Two twin pairs reported no incontinence. One pair reported incontinence with activities and stress incontinence was confirmed with VLPP of 120 and 130 cm H(2)O in the nulliparous and parous sister respectively. In one pair only the nulliparous sister reported incontinence, however both sisters were diagnosed with stress incontinence with VLLP of 130 and 120 cm in the nulliparous and parous sister respectively. Using POP-Q staging for relaxation of the pelvic support system, only one twin pair had a greater than 1 stage difference in any compartment.

Conclusions: All four pairs of identical twins were diagnosed with identical continence status. Three pairs were identical with regard to support in all three compartments. Vaginal delivery was not associated with urinary incontinence or clinically relevant differences in relaxation of the pelvic support system within four sets of postmenopausal identical twins with different parity status.