Pre-eclampsia and the risk of cancer

Several studies suggest a decreased risk—except this one

This issue of the BMJ includes a study which examines the relation between pre-eclampsia and cancer.1 Many researchers have suggested that pre-eclampsia or hypertension in pregnancy is associated with a reduced risk or no excess risk of cancer in the mother.2^–8 However this week's study by Paltiel et al shows an increased risk of cancer after pre-eclampsia.1

Despite decades of research, there is still confusion over the cause of pre-eclampsia. It is relatively common, affecting 3-5% of pregnancies, and is a leading cause of morbidity and mortality both in the mother and unborn child.9 Several observational studies in European and North American populations have examined the relation between pre-eclampsia (or hypertension) in pregnancy and cancer.2^–8 Unfortunately some were based on a small number of cancers in the pre-eclampsia group, not all adjusted for known confounders, and the length of follow up varied. Most of these studies found a …