The findings, just published on-line in the prestigious BJOG, international journal of Obstetrics and Gynaecology, cast doubt on the frequently-made claim that C-section deliveries protect women from incontinence, and also on the belief that having a C-section means women retain better sexual capability or function than those who have vaginal births.
At 12 years in length, this is the longest and most comprehensive international study into this controversial issue of whether or not caesarean births confer women with protective qualities against some of the long-term negative effects of childbirth.
It involved researchers from the University of Otago, the University of Birmingham and the University of Aberdeen, who surveyed 3763 women at three months after giving birth, at six years and at 12 years.
It was jointly funded by the University of Otago and the organisation “Wellbeing of Women” at the Royal College of Obstetricians and Gynaecologists in the UK.
One of the lead researchers, Otago’s Professor of Obstetrics and Gynaecology Don Wilson, says the study clearly documents that having a C-section does not protect women from experiencing urinary incontinence (UI) unless women have all their babies by C-section – in which case women can be less prone to UI. But a woman who has both a baby vaginally, and a child via C-section, not necessarily in that order, has the same propensity to develop urinary incontinence as a woman who has only ever had vaginal births.
The results also highlight that there is no difference in levels of faecal incontinence (FI) between women who has only ever had spontaneous natural deliveries and only ever had C-sections.
Furthermore, when surveyed at six years after giving birth, there was almost no difference in women’s rating of their sexual function between those who had caesarean births and those who had vaginal births.
In the paper, the key findings were that 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 – although this was still considered high.
“The findings of this large cohort study comprise an important new message to inform choice of delivery by caesarean section: Unless women are resolved to have all their deliveries by the abdominal route (and their medical advisers agree), there is no protection from subsequent urinary incontinence with caesarean section,” the researchers concluded in the BJOG.
Professor Wilson says regardless of how they delivered their children, women who were older when they first had a baby (in the 35-year-plus age group), were heavier or had given birth more times, reported higher rates of incontinence.
He says the study’s strength lies in its longitudinal design and the large cohort, drawn from three different maternity units; Dunedin, New Zealand; Birmingham in England and Aberdeen in Scotland.
Women were sent questionnaires asking about loss of control of their bladder or bowel motions three months after giving birth, at six years and at twelve years after giving birth. The main question the researchers were trying to assess was whether the way they gave birth was predictive of incontinence 12 years after giving birth.
Professor Wilson says he and his colleagues Preventive and Social Medicine Professor Peter Herbison, plan to follow-up the women in 2014, at 20 years after the women have given birth.
The study started in 1993 as a randomised trial to ascertain whether exercises to strengthen pelvic floor muscles after birth actually worked.
“We realised we had this massive data base that we could use for other studies,” he says.
Other lead authors on the study were Professor Christine MacArthur ofthe University of Birmingham and Dr Cathryn Glazener, of the University of Aberdeen.
For further information, contacts
Professor Don Wilson
Tel 64 3 474 7951, ext 8570
Professor Peter Herbison
Tel 64 3 4797217