Women who put on more weight during their pregnancy than what is generally recommended are more likely to undergo a caesarean delivery. Researchers from the University of California, San Francisco, USA, found that among nearly 9,800 first-time mothers, women who gained more weight were more likely to undergo a of caesarean section, even if the baby was not large. The study suggests that it is something about excess maternal weight gain itself, which makes a caesarean more likely. Heavy birth weights i.e. 8 pounds (approximately 3.6 kg) or more increase the odds of needing a caesarean section. For optimal health of the mother and newborn, women should gain only 25 to 35 pounds during pregnancy, while overweight women should put on no more than 25 pounds. However, it's known that many women fall outside of these ranges. In the study, 48 per cent of the women gained more than the recommended weight, while 17 per cent gained less. Overall, women who gained excessive weight were 40 per cent more likely to have a caesarean section than those who stayed within the recommended range. Investigators estimate that of the 288,000 caesarean sections performed each year on first-time mothers in the U.S., 64,000 would be prevented if no woman exceeded the recommended weight gain limits. Exactly why excess weight gain may lead to C-section in some cases is unclear. Hormone levels, influenced by fat tissue may come into play, as might excess soft tissue, which could hinder vaginal delivery. It was only among initially normal-weight women that excess weight gain raised the odds of caesarean section. Overweight women who gained more than 25 pounds had a caesarean rate similar to that of women who fell within the normal range.
Obstetrics & Gynecology,
October 2004