The effect of recurrent miscarriage and infertility on the risk of pre-eclampsia.

OBJECTIVE

Pre-eclampsia, recurrent miscarriage and infertility may all partly be caused by unsuccessful placentation early in pregnancy. If so, one will expect these disorders to be associated in population studies. The aim of the present investigation was to estimate the risk of pre-eclampsia in women with recurrent miscarriage and infertility.

DESIGN

Cohort study.

SETTING

The Norwegian Mother and Child Cohort Study (MoBa), a large population-based pregnancy cohort.

SAMPLE

The sample consisted of 20,846 singleton pregnancies to nulliparous women participating in the MoBa, 1999-2005.

METHODS

Information on miscarriage, infertility and potential confounders was self-reported in postal questionnaires, whereas the diagnosis of pre-eclampsia was retrieved from the Medical Birth Registry of Norway. Risk estimation and confounder control was performed with multiple logistic regression.

MAIN OUTCOME MEASURES

Pre-eclampsia according to history of miscarriage and infertility.

RESULTS

An increased risk of pre-eclampsia, although not statistically significant, was found for women with recurrent miscarriages (adjusted OR 1.51, 95% CI 0.80-2.83). Women who had ever been treated for infertility also had increased risk (adjusted OR 1.29, 95% CI 1.05-1.60). When these two risk factors were combined, the adjusted odds ratio for pre-eclampsia was 2.40 (95% CI 1.11-5.18).

CONCLUSIONS

The study supports the hypothesis that infertility, recurrent miscarriage and pre-eclampsia share elements of the same aetiological factors.