Pregnant women don't plan for pre-eclampsia. The condition only affects two percent of pregnancies; so most women manage to avoid having to deal with the high blood pressure and resulting complications in their pregnancy. For those who find themselves faced with it, it is a monster of sizeable proportions.

The higher blood pressure in mum causes danger to her because of the high level of elevation, but there is also significant risk to her unborn child as well. It also prevents the placenta from receiving sufficient blood flow, causing great peril to the infant. The only "cure" is early delivery of the baby, which brings attendant risks of its own. Medication is sometimes used to try and bring the threats to both mum and infant down to a more acceptable level, with mixed results.

John Higgins from the University College Cork monitored almost a thousand healthy women in their early to late twenties who were pregnant with their first child. He and his colleagues split the women into three groups for the purposes of their research: those who were working, those who had chosen not to work during their pregnancy and those who were not employed.

The team discovered that women in the working group had a significantly higher risk of going on to develop pre-eclampsia, almost five times greater than their non-working counterparts. This remained true even after accounting for other standard risk factors, such as age, smoking and weight. Their theory is that those women had the highest stress level, which led to the highest blood pressure, which in turn lead to the increased risk for pre-eclampsia.