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Cardiovascular mortality after pre-eclampsia in one child mothers: prospective, population based cohort study

BMJ 2012; 345 doi: (Published 27 November 2012) Cite this as: BMJ 2012;345:e7677

Re: Cardiovascular mortality after pre-eclampsia in one child mothers: prospective, population based cohort study

Dear Editor,

I read with interest the recent study by Skjaerven and colleagues concluding that, cardiovascular death in women with pre-eclampsia in their first pregnancy is concentrated mainly amongst women with no additional births.

It appears that the unmeasured variables in this study might be the key to explaining the findings. Underlying maternal cardiovascular risk factors, obesity, smoking, and information on why women might have had only one child was not recorded. Similarly, other risk factors, including history of psychiatric conditions (e.g. bipolar disorder) were also absent. Although it might be that the pre-eclampsia was a precursor to developing cardiovascular disease, another plausible explanation is that amongst these women pre-eclampsia was an indication of the woman’s poor mental/physical health or wellbeing in the perinatal period (which might explain why they had no additional pregnancies/births).

This idea is further reinforced when we look at the mortality outcomes of fathers. The authors found that fathers with only one child also have an increased risk of early death. This might suggest the role of social variables, or unmeasured factors such as obesity, depression in the father, or social/family set-ups, in mitigating the likelihood of having further children. For instance, compared to women with a low level of education, women with a high level of education and only one child had a larger increase in risk of cardiovascular death if they had a pre-eclamptic first pregnancy. It is known that couples with a high level of education often have to move away from their hometowns in order to pursue their careers thus rendering the opportunities for support in child-rearing by family members limited; both predisposing partners to stress in juggling the responsibilities of a family with a career, and possibly discouraging them from having more children. Until we have more of an understanding of the potential causes of pre-eclampsia, including the interplay of lifestyle and social factors, we cannot conclude that pre-eclampsia itself is linked to cardiovascular mortality amongst these women.

Competing interests: No competing interests

06 December 2012
Oya Eddama
Health Economist
National Perinatal Epidemiology Unit
University of Oxford, Oxford, OX3 7LF