When Lady Sybil, a wealthy British aristocrat in the popular television shown Downton Abbey, died of eclampsia during an episode set in 1920, it was a reminder of the progress that mankind has been made on maternal mortality. Despite being able to afford the best medical care of the day, Lady Sybil suffered from the most common of prenatal complications.

Affecting 6 per cent of all pregnancies, preeclampsia raises a pregnant woman’s blood pressure to dangerously high levels, and if left untreated, often results in violent seizures (eclampsia). It can lead to the death of the mother, the child, or both. Historically, no amount of wealth or privilege could save a woman from the horrific condition.

The World Health Organization defines maternal mortality as “the death of a woman while pregnant or within 42 days of termination of pregnancy.” Such deaths can occur for a variety of reasons, including bleeding and infection after childbirth, high blood pressure during pregnancy, complications during delivery and unsafe abortion.

Early statistics are difficult to come by, but British parish records indicate a maternal mortality rate of 1,000 per 100,000 live births in the first half of the 18th century. Since women were pregnant more often than is the case today, the actual risk of dying due to complications from pregnancy would have been much higher.

Preeclampsia’s exact cause is unknown, although it seems to begin with improperly functioning blood vessels in the placenta. There is no surefire way to prevent the condition. Some of the risk factors — such as advanced maternal age, obesity, or having children less than two years apart — can be avoided, but preeclampsia can still strike women without any known risk factors. Researchers have found some evidence that low-dose aspirin or calcium supplementation can reduce the risk of developing the condition.