Women who are obese are 2.4 times more likely to develop a surgical wound infection after a caesarean section, according to a study published online today by BJOG: An International Journal of Obstetrics and Gynaecology.
Overall, one in ten women develop a post-surgical infection following the procedure, with between 1.2 and 5% of women developing the infection during their inpatient stay, found a team of researchers from the Health Protection Agency (HPA).
The proportion of births delivered by caesarean section in England has risen over the past 30 years from 9% in 1980 to 25% in 2009-10.
For the study, the researchers looked at data from 4,107 operations from 14 acute hospitals across England, which were carried out in 2009.
The volunteers – women of an average age of 31(range 14-56) – came from 14 hospitals already participating in the HPA’s Surgical Site Infection Surveillance Scheme.
In total, 394 surgical site infections were identified from 4,107 operations, which was equivalent to a risk of 9.6%.
Of the 394 infections, 348 were superficial incisional affecting the skin and surface layers, 19 deep incisional (affecting deeper tissues) and 27 organ/space infections (affecting internal organs) including endometritis (infection of the womb lining) and reproductive tract infections.
On average, it took 10 days for all site infections to develop and eight days for deep and organ/space infections. Of all the women, 23 were readmitted to hospital for treatment of their infection.
The researchers also found that obesity and young age (under 20 years old) were associated with the development of an infection after a caesarean.
Compared to women with a normal body mass index (BMI) of 18.5 to 25, overweight women (BMI 25-30) were found to have a 1.6 times greater risk of infection than normal weight women, and obese women (BMI more than 30) 2.4 times greater risk.
In addition, there was some evidence of an increased likelihood of infection in women aged less than 20 who had a 1.9 times greater risk compared to women 25-30 years.
Dr Catherine Wloch, of the Department of Healthcare Associated Infection and Antimicrobial Resistance at the HPA and lead author of the paper said: “Although most caesarean section wound infections are not serious, they do represent a substantial burden to the health system, given the high number of women undergoing this type of surgery.
“Minor infections can still result in pain and discomfort for the woman and may spread to affect deeper tissues. The more serious infections will require extended hospital stays or readmission to hospital. Prevention of these infections should be a clinical and public health priority.”
John Thorp, BJOG deputy-editor-in-chief said: “With the rise in numbers of women having a caesarean section and the rise in obesity rates, this issue is an important one.
“Post-surgical infection can seriously affect a woman’s quality of life at a critical time when she is recovering from an operation and has a new born baby to look after.”
A Department of Health spokesperson said: "We keep all emerging findings under review. Whether to have a caesarean or not remains a decision that a woman must reach with the health professionals providing her care. Decisions should take NICE guidance into account.
"Annually the numbers of MRSA and C.difficile infections are now at their lowest ever level since mandatory reporting for each was introduced. Hospitals should extend measures that have reduced the number of these infections across all areas."