Associate Professor Kirsten Black and Kate Cheney analysed the data for 42 582 first-time mothers with singleton pregnancies who gave birth at the Royal Prince Alfred Hospital in Sydney between January 1990 and December 2014.
They found that the prevalence of overweight among first-time pregnant women increased from 12.7% in 1990–1994 to 16.4% in 2010–2014; the prevalence of obesity rose from 4.8% to 7.3% over the same period, while the proportion of women with a normal range body mass index (BMI) fell from 73.5% to 68.2%.
The researchers estimated population attributable fractions (PAFs), the proportional reduction in population disease that could be achieved were exposure to overweight and obesity reduced to a more desirable level.
They found that the PAFs for adverse maternal and neonatal outcomes increased across the study period; during 2010–2014, 23.8% of pre-eclampsia, 23.4% of fetal macrosomia, and 17.0% of gestational diabetes were attributable to overweight and obesity.
“Were overweight and obese women to have moved down one BMI category during 2010–2014, 19% of preeclampsia, 15.9% of macrosomia, 14.2% of gestational diabetes, 8.5% of caesarean deliveries, 7.1% of low for gestational age birthweight, 6.8% of post partum haemorrhage, 6.5% of admissions to special care nursery, 5.8% of prematurity, and 3.8% of fetal abnormality could have been averted,” the authors wrote.
Prevention essential
They added preventive strategies should shift to helping women prior to becoming pregnant.
“Expert national and international consensus statements support improving pre-conception health and detailed prevention strategies. They recommend reducing obesity as a means for improving reproductive health outcomes, and potentially also reducing societal costs. The National Health Summit on Obesity called for federal support for life course strategies that incorporate pre-conception care.
“We found that a substantial proportion of the burden of adverse perinatal outcomes for Australian women is linked to maternal overweight and obesity, and that this proportion has steadily increased over the past 25 years. Importantly for practice and policy, our results indicate that the frequency of adverse perinatal outcomes could be reduced by shifting the distribution of overweight and obesity among first-time mothers by a single BMI class.
“Investing in obesity prevention strategies that target women prior to their becoming pregnant is likely to provide the greatest benefit,” they concluded.
Source: Medical Journal of Australia.
"Population attributable fractions of perinatal outcomes for nulliparous women associated with overweight and obesity, 1990-2014."
Authors: Kirsten Black and Kate Cheney.