Women who work during pregnancy are almost five times more likely to develop pre-eclampsia, a potentially fatal condition that causes abnormally high blood pressure, researchers warn today.
The results of their study of 933 women using the Rotunda maternity hospital in Dublin will reinforce speculation that work stress might increase stress hormones and trigger a nervous response that raises blood pressure.
The report, published in the Journal of Epidemiology and Community Health, will heighten the debate over how dangerous working is for pregnant women although its authors did not assess what type of work might be most associated with developing pre-eclampsia.
But more women than ever are choosing to work outside their homes during pregnancy and the effect of this trend on them and their babies remains controversial.
The women, all in their early to late 20s and between 18 and 24 weeks into their first pregnancy, had their blood pressure monitored over 24 hours as they went through their daily routines.
Of these, 245 were working, 289 were not working, and 399 were employed but chose not to work while their blood pressure was being monitored. Those who were working had the highest blood pressure readings. Older women tended to have higher blood pressure, but there were more smokers among the younger women.
There were no differences between the three groups in length of pregnancy, birthweight of their babies or method of delivery, induction or caesarian section. Yet working women were far more likely to go on to develop pre-eclampsia, irrespective of other factors known to influence blood pressure, such as smoking, drinking, height, weight and age.
The authors said that the fact they found little difference in blood pressure levels between those who were not working at all and those who chose not to work while being monitored suggested the relation of work to high blood pressure "may be both causal and reversible". It would be important to compare blood pressures for an individual on a work day with those on a non-work day.
They point out that many women developed high blood pressure in pregnancy, a condition known as pregnancy hypertension, but this posed little risk to mothers or children and usually disappeared after birth. It did not automatically predispose women to pre-eclampsia, which can cause potentially fatal blood poisoning and swelling in hands, feet and ankles.
