Women who have had preeclampsia are at increased risk of cardiovascular disease later in life, suggesting that they should be targeted for primary prevention, according to a British review published online in the British Medical Journal.
Meanwhile, an accompanying population-based prospective study in Norway suggests that cardiovascular risk factors are associated with a higher risk of preeclampsia.
“The underlying link between preeclampsia and cardiovascular disease is unclear. Although preeclampsia may initiate endothelial damage, it is thought to be more likely that preeclampsia and cardiovascular disease have a common pathogenesis rooted in shared risk markers,” wrote Dr. Laura Magee and Dr. Peter von Dadelszen of the University of British Columbia, Vancouver, in a commentary accompanying the two studies (BMJ 2007 Nov. 2 [Epub doi.10.113/bmj.39337.427500.80]).
In the first study–a review of cohort studies in all languages between 1960 and 2006 covering more than 3 million women–British researchers found an increased risk for vascular disease among women who'd had preeclampsia, compared with those who never had the disorder. The relative risks for women with a history of preeclampsia were 3.7 for hypertension after a mean weighted follow-up of 14 years, 2.2 for ischemic heart disease after 12 years, 1.8 for stroke after 10 years, 1.8 for venous thromboembolism after almost 5 years.
No increase in the risk of any cancer was found, including breast cancer, after 17 years, wrote Leanne Bellamy, a medical student at Imperial College School of Medicine, London, and her associates (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39335.385301.BE]).
The overall risk of mortality was elevated following preeclampsia, with a relative risk of 1.49 after 14.5 years.
“We must recognise that these women are still young, their absolute risk of cardiovascular disease is low over the short term, and their risk will evolve over subsequent decades,” wrote Dr. Magee and Dr. von Dadelszen in their commentary. “As such, we have an opportunity for primary prevention, especially as cardiovascular disease is largely preventable.”
They added, however, that the findings so far do not help physicians guide their primary prevention strategy. No evidence supports how to screen younger women for risk factors, and while recommending lifestyle change is good for all patients, such a recommendation “is not enough to change their behavior,” the authors wrote. “However, women might be more receptive if they have had a complicated pregnancy. Perhaps we could tailor the advice to women with newborns and young children,” they wrote.
The Norwegian study tracked 3,494 women who gave birth after participating in the Nord-Trøndelag health study to link cardiovascular risk factors and preeclampsia risk. The women were linked to diagnoses for preeclampsia through the Norway birth registry (BMJ 2007 Nov. 2 [Epub doi:10.1136/bmj.39366.416817.BE]).
After adjustment, the odds ratio for preeclampsia in women with a baseline systolic blood pressure greater than 130 mm Hg (highest fifth) was 7.3, compared with those with a systolic blood pressure less than 111 mm Hg (lowest fifth). Similarly, the odds ratio for women with a diastolic blood pressure greater than 78 mm Hg was 6.3, compared with those whose diastolic pressure was less than 64 mm Hg.
Women who were overweight or obese had a higher risk of preeclampsia than did women of normal weight, and the risk for preeclampsia rose with increasing waist circumference.
In addition, there was a weak association between pregnancy lipid levels in the clinically normal range and preeclampsia, and a stronger association with lipid levels above the normal range.
“We found that cardiovascular risk factors that were present years before pregnancy are associated with a risk of preeclampsia,” wrote Elisabeth Balstad Magnussen, a research fellow at the Norwegian University of Science and Technology, Trondheim, and associates. “This finding suggests that unfavourable cardiovascular and metabolic profiles may represent primary causes of preeclampsia and that these factors predispose both to preeclampsia and to subsequent cardiovascular disease. This does not, however, rule out the possibility that the pre-eclamptic process in itself may also contribute to cardiovascular risk.