Background: Epidemiological studies show a substantially reduced risk of breast cancer in adult daughters of preeclamptic pregnancies, and modest risk reductions have been demonstrated for mothers also. Alterations in pregnancy hormone concentrations, particularly lower in utero exposure to oestrogen, are hypothesized to mediate this association.
Methods: Pregnancy hormone concentrations were measured in maternal sera collected at hospital admission for labour and delivery from 86 preeclamptic and 86 uncomplicated, singleton pregnancies matched on length of gestation, maternal age, parity, and type of delivery.
Results: Case and control pregnancies were similar in several maternal and pregnancy factors. Serum unconjugated oestradiol, oestrone, and oestriol concentrations were not lower in preeclamptic pregnancies in a matched analysis with adjustment for race and whether blood was collected before or after labour commenced. Serum unconjugated androstenedione (506.3 versus 316.0 ng/dl; P = 0.0007) and testosterone concentrations (214.5 versus 141.9 ng/dl; P = 0.004), however, were significantly higher in preeclamptic compared with control pregnancies, whereas dehydroepiandrosterone (DHEA) and DHEA sulphate did not differ.
Conclusions: These data do not support the hypothesis that cancer risk in mothers and offspring of preeclamptic pregnancies is explained by exposure to lower maternal blood oestrogen concentrations, but raise the possibility that androgens play a role.