Having a Caesarean section may not lower a woman's chance of incontinence later in life unless she delivers all of her children that way.
The findings question the suggestion that by choosing a C-section over vaginal delivery, women might be protecting themselves against urinary or faecal incontinence down the road.
Breathing problems in babies
And they "comprise an important new message to inform the choice of delivery by Caesarean section", the authors wrote in BJOG: An International Journal of Obstetrics and Gynaecology.
Recent evidence shows that the rate of C-sections performed in the U.S. has been rising, from one in five births in 1996 to almost one in three births in 2007, according to the Centres for Disease Control and Prevention.
Read: Risk Factors for incontinence
Many doctors see this trend as risky because C-sections have been linked to a higher chance of breathing problems in babies and future pregnancy complications in moms.
In the current study, Dr Cathryn Glazener of the University of Aberdeen in the UK and her colleagues tracked almost 4,000 women who gave birth in the UK and New Zealand for 12 years after their delivery.
After recording how those first babies were delivered, the researchers kept in touch with women through questionnaires to find out if they had more children, and whether those children were born through C-sections or vaginal deliveries.
Read: Pregnancy weight , incontinence linked
They also followed up with the participants to ask if they had symptoms of urinary or faecal incontinence, and if so, how often.
At the end of the 12 years, just over half of women reported urinary incontinence, and a quarter had symptoms at least once a week.
In women who had given birth only through vaginal delivery, 55 percent reported experiencing urinary incontinence.
That compared to 59 percent of women who had at least one baby through vaginal delivery and one via C-section. In women who only had C-sections, the rate of urinary incontinence fell to 40 percent.
Read: The 4 types of urinary incontinence
Rates of faecal incontinence 12 years down the line were about the same – between 11 and 14 percent – in women who had only given birth through vaginal deliveries or C-sections alone, or had given birth through both modes of delivery.
Regardless of how they delivered their children, women who were heavier, had given birth more times, and were older at their first delivery reported higher rates of incontinence.
Glazener told Reuters Health that vaginal delivery has been thought to cause urinary incontinence through physical trauma and damage to nerves.
She and her colleagues concluded, "Unless women are resolved to have all their deliveries by the abdominal (C-section) route (and their medical advisors agree), Caesarean section does not protect from subsequent urinary incontinence."
Urinary incontinence in menopause