Objective: To isolate epidemiological risk factors for menorrhagia.
Methods: Menstrual blood loss (MBL) of one bleeding episode of 182 healthy women was measured with the alkaline hematin method and the results were related to age, parity, body mass index and smoking habits. Multiple and logistic regression analysis was performed to isolate the variables that most influence MBL. Two consecutive menstrual episodes were measured in 117 women, to determine individual constancy.
Results: MBL increased significantly with age (Kruskal-Wallis, P < 0.03) and the percentage of women with menorrhagia was significantly higher above 40 years of age (Mann-Whitney's ranks sum test, P < 0.05). The odds ratio of parous:nulliparous women for menorrhagia was 2.27:1, but after adjustment for age this influence disappeared. Body mass index and smoking habits were not significantly related to menorrhagia. The mean difference between the MBL of two consecutive menstruations is 2.1 ml (S.E.: 1.7, 95% CI: -1.3 to 5.5 ml).
Conclusions: Only age could be indicated as a risk marker for menorrhagia. Parity, body mass index and smoking habits appear to have no significant effect on MBL, when adjusted for age. The individual constancy in MBL between two consecutive cycles is very high and therefore one single measurement suffices in studies of MBL.