Credit: Original article published here.
Researchers of a study noted data on breast cancer risk conflict in describing an inverse association with preeclampsia but a positive association with preterm birth—which is linked to preeclampsia. The authors evaluated concurrent preeclampsia or gestational hypertension plus preterm birth and risk of breast cancer.
According to the lead author, Hazel Nichols, analysis of 6 cohorts of women with breast cancer suggested premenopausal breast cancer had an inverse association with preeclampsia, and no significant association with preterm birth. Their findings were presented in Breast Cancer Research and Treatment.
Negative Correlation Between Preeclampsia and Breast Cancer Risk
The study included a total of 3096 premenopausal breast cancers from 184,866 patients. Researchers used a Cox proportional hazard regression model to estimate hazard ratios (HRs) for breast cancer risk.
Notably, the authors found preterm birth was not associated with premenopausal breast cancer risk (HR, 1.02; 95% CI, 0.92-1.14), while preeclampsia was inversely associated with risk (HR, 0.86; 95% CI, 0.76-0.99). Additionally, in subgroup analyses using 3 cohorts, the association between preterm birth and breast cancer risk differed in patients with hypertensive first pregnancies (P=.09).
Researchers reported preterm birth was positively associated with premenopausal breast cancer in patients with preeclampsia or gestational hypertension (HR, 1.52; 95% CI, 1.06-2.18), and not in patients with normal blood pressure during pregnancy (HR, 1.09; 95% CI, 0.93-1.28).
The inverse relationship between preeclampsia and breast cancer risk was slightly stronger in patients who delivered preterm (HR, 1.07; 95% CI, 0.73-1.56) compared with those who did not (HR, 0.82; 95% CI, 0.68-1.00), but the difference was not significantly different.
Ultimately, “findings support an overall inverse association of preeclampsia history with premenopausal breast cancer risk,” the authors summarized. “Estimates for preterm birth and breast cancer may vary according to other conditions of pregnancy.”
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