It’s normal to gain weight during pregnancy. It ensures a mother and her baby stay healthy through to birth but what constitutes healthy weight gain is a bit trickier. For normal weight women, gaining between 11.5 and 16 kilograms is recommended. If the mother is overweight, she shouldn’t feel the need to start a diet but it is recommended to limit weight gain to between five and 11.5 kilograms. The tough truth is that obesity is associated with negative outcomes for mother and baby.

In this study, researchers looked at all births of new mothers at Sydney’s Royal Prince Alfred Hospital between 1990 and 2014. Electronically recorded data contained the height, weight, medical and pregnancy history of all the women who gave birth. From that, the researchers calculated the BMI of each woman. Those figures were then correlated to the outcomes of the birth for each mother and child – including the baby’s birth weight, if they had any congenital abnormalities and if they were stillborn. In all, they analysed more than 42,000 births for the study.

The researchers found that controlling for factors such as maternal age, smoking and socio-economic status, being overweight or obese increased the risks of a number of negative outcomes for mothers and babies. They included gestational diabetes, pre-eclampsia and post partum haemorrhage. The risk of stillbirth and fetal abnormality were higher for women who were obese. The study also showed that rates of overweight and obesity in pregnant women have risen over time. Rates of obesity rose from 4.8 per cent to 7.3 per cent between 1993 and 2014.

Implications

Women who are overweight and pregnant or thinking of having a baby should be encouraged to lose weight. If possible, achieving a healthy weight pre-conception is the ideal outcome.

Last Reviewed: 18/07/2018

© Norman Swan Medical Communications.



References

Cheney, et al. (2018). Population attributable fractions of perinatal outcomes for nulliparous women associated with overweight and obesity, 1990–2014. Medical Journal of Australia doi: 10.5694/mja17.00344.