The babies of women who are obese during pregnancy are at a significantly increased risk of dying before, during or up to one year after their birth, the results of a new study indicate.
UK researchers looked at 40,932 single baby pregnancies. The babies were delivered at five maternity units in England between 2003 and 2005.
The study found that women who were obese in early pregnancy had nearly double the risk of the baby dying in the womb (foetal death) or up to one year after birth (infant death) than women who were of a recommended weight.
The researchers from Newcastle University estimated that there were almost eight more foetal and infant deaths per 1,000 births among obese women than among women with a recommended body mass index (BMI).
The total risk among obese women was 16 in every 1,000 births (1.6%) compared to nearly nine per 1,000 births (0.9%) in normal weight women.
A study carried out at Dublin's Coombe Hospital last year found that over one-quarter of pregnant women in Ireland are overweight, while 15% are obese or morbidly obese.
"What's key is that women should be helped to achieve a healthy weight before they become pregnant or after the baby is born. Our research shows that this will give the baby the best possible start in life. Women should not try to lose weight during pregnancy, but should ensure they eat a balanced healthy diet," commented one of the study's authors, Dr Ruth Bell.
One reason for the increased risk of foetal and infant death in obese women was due to a higher proportion of deaths from pre-eclampsia, a serious pregnancy complication characterised by high blood pressure and protein in the urine. However, deaths due to other causes were also more common in obese women.
The researchers adjusted their results to take account of the mothers' age, ethnicity, smoking status, socioeconomic status and excluded pregnancies where the baby had a congenital anomaly (e.g. spina bifida) or where the mother had a history of diabetes - both of which are associated with maternal obesity and increase the risks of foetal and infant death.
"Given the rising prevalence of obesity in the population of pregnant women, the rates of miscarriage, stillbirth and infant mortality can be anticipated to increase," the researchers concluded.
Details of these findings are published in the journal, Human Reproduction.
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