Tel Aviv, Israel--Twin pregnancy per se, with no trial of labor, increases the risk of postpartum stress urinary incontinence, according to a prospective study by obstetrician-gynecologists from Tel Aviv University, Israel.
Their investigation compared the incidence of new-onset stress incontinence between two groups of primiparae women-one including 118 women with a singleton pregnancy and the second consisting of 50 women who delivered twins. All of the women had elective Cesarean section and none had stress incontinence prior to pregnancy.
Follow-up at 1 year postpartum showed the women who bore twins were three-fold more likely to have symptoms of stress incontinence compared with those with a singleton pregnancy (10% vs. 3.4%, respectively). The difference in incontinence rates between the study groups was statistically significant.
All patients were recruited for study participation immediately after delivery, and they were consecutively enrolled. Presence of postpartum stress incontinence was identified through patient self-reports during interviews. Women were asked if they experienced any involuntary leakage of urine upon coughing, sneezing, laughing, or with any other physical effort. Only women reporting such loss at least two times per month were categorized as having symptoms of SUI.
Other data collected included maternal age, weight, height, gestational age at delivery, indication for Cesarean section, birth weights, and Apgar scores. No differences were seen between the singleton and twin pregnancy groups with respect to the maternal demographic features, and the most common indication for elective Cesarean section in both groups was non-vertex presentation.
Total fetal weight is a predictor However, the analysis did find a trend for higher total fetal weight at birth to be a predictor of SUI. Within the twin pregnancy group, incontinent women had a higher total fetal weight relative to their continent counterparts-4,988 grams vs. 4,542 grams, respectively.
At the 2003 AUA meeting, the Israeli investigators presented a study indicating that among women with singleton pregnancies, elective cesarean section seemed to protect against stress incontinence (Neurourol Urodyn 2004; 23:2-6). That study included 363 consecutive primiparae women, of whom 145 had spontaneous vaginal delivery, 118 delivered by elective cesarean section with no trial of labor, and 100 underwent C-section after obstructed labor.
The incidence of de novo stress incontinence was significantly less among the women who had elective cesarean section (3.4%) compared with both those who had spontaneous vaginal delivery (10.3%) and cesarean section performed for obstructed labor (12%).
"It is quite possible that pelvic floor insult occurring during pregnancy and prior to labor and delivery is increased in twin pregnancies secondary to increased mechanical strain. Further studies are needed to establish if vaginal delivery of twins is associated with further insult," said Asnat Groutz, MD, lead author of the current study, which was presented at the 2004 AUA annual meeting.
Additional studies examining factors affecting SUI risk in mothers of multiples are underway, Dr. Groutz said.