CV death rate high for one-child mothers with preterm preeclampsia

Risk for CV mortality later in life is nearly 10 times higher for one-child mothers with preterm preeclampsia than for women without preeclampsia who go on to have more than one child, researchers reported in the British Medical Journal.

Researchers in Norway assessed the association of preeclampsia with later CV mortality in mothers according to their lifetime number of pregnancies, and particularly after only one child. Using the Medical Birth Register of Norway, they tracked 836,147 Norwegian women with a first singleton birth between 1967 and 2009 for CV mortality.

More than 23,000 women died by 2009, 3,891 were related to CV causes. Overall, the rate of CV mortality was higher for women with preeclampsia during the first pregnancy compared with women without the condition at first birth (adjusted HR=1.6; 95% CI, 1.4-2 after term preeclampsia; HR=3.7; 95% CI, 2.7-4.8 after preterm preeclampsia).

Large differences in risk emerged when evaluating risks to one-child mothers with those of other mothers. Among one-child mothers, the increase in risk for CV mortality was high (adjusted HR=3.4; 95% CI, 2.6-4.6 after term preeclampsia; HR=9.4; 95% CI, 6.5-13.7 after preterm preeclampsia). Women with preeclampsia during the first pregnancy, who went on to have additional children, were at only moderately high risk for CV mortality (adjusted HR=1.5; 95% CI, 1.2-2.0 after term preeclampsia; HR=2.4; 95% CI, 1.5-3.9 after preterm preeclampsia).

Evaluated as cumulative risk after 42 years, CV mortality for women with preterm preeclampsia was 9.2% after having only one child, while only 1.1% after two or more children. Among women with term preeclampsia, the risks were 2.8% and 1.1%, respectively.  

Probably the most important result of the study was found when studying all-cause mortality, according to lead author Rolv Skjaerven, MD, from the department of public health and primary health care, University of Bergen, Bergen, Norway. Women with preeclampsia in first pregnancy and two or more children have an excess in CV death, but they have a reduced risk for deaths due to other causes. The net effect for these two plus mothers is no overall excess death following preeclampsia. This is a very positive message since as much as 85% of mothers (in Norway) have two or more children, Skjaerven told Cardiology Today via email.

“[We] expected that the strong correlation we usually see in successive outcome for women would show higher mortality for recurrent preeclamptic events. We did not find that. The surprise was the strong effects for one-child mothers. There is an effect on women with preeclampsia in later pregnancies, but not close to the effect of the one-child affected mothers,” Skjaerven said.

Moving forward, Skjaerven suggested increased focus on the “smaller group of women that stop reproduction after one child.” – by Deb Dellapena

Disclosure: The study was supported by grants from the Norwegian Research Council and the Intramural Research Program of the National Institute of Environmental Health Sciences, National Institute of Health. Skjaerven reports no relevant financial disclosures.