Between February 2005 and August 2006, Oxford University researchers used the UK Obstetric Surveillance System to study pregnancy data on over one million women, 141 of whom were diagnosed with an antenatal pulmonary embolism.
They found 28% of those with an antenatal pulmonary embolism had a BMI greater than 30 compared with just 16% of women in a control group who suffered no embolism.
Lead study author Marian Knight, senior clinical research fellow at the university’s national perinatal epidemiology unit, said: ‘Pulmonary embolism remains an important cause of death in pregnant women in the UK, and overweight and obese pregnant women are particularly at risk.
‘This is an especially important observation given the increasing prevalence of obesity in our population,’ she added.
Mervi Jokinen, RCM practice and standard development adviser, said women should be informed about obesity dangers prior to becoming pregnant.
‘Rates of obesity are increasing in pregnant women and the average starting weight [on becoming pregnant] is higher than 10 years ago,’ she said. ‘Education about diet management, increasing activity levels and exercise should start at pre-conceptual care.’
The study findings are due to be published in the British Journal of Obstetrics and Gynaecology.
A second piece of research, to be published in the same journal, may have identified a cause of
pre-eclampsia in pregnancy, an important risk factor for venous thromboembolism that occurs in up to 10% of first pregnancies.
Although the main cause of the condition is unknown, Australian researchers claim to have found a connection between pre-eclampsia and exposure to viral infection, particularly viruses of the herpes group.
‘This is an exciting finding and further studies are now required to look at the link between viral exposure in pregnancy and genetic susceptibility to adverse pregnancy outcomes,’ the researchers said.