[Changes in bone mineral density of postmenopausal women in relation to the menstrual cycle length]

There is a strong relationship between the age of menarche, the length of the menstrual cycle and menstrual bleeding and fracture risk in the postmenopausal period.

Evaluation of the menstrual cycle length and lumbar bone mineral density in postmenopausal women.

We investigated three groups of postmenopausal women (each - n = 50). The first group included women with menstrual duration of 27 days during reproductive age, the second group included postmenopausal women with menstrual duration of 28 days during the reproductive age, and the third group consisted of postmenopausal women with menstrual duration of 30 days during reproductive age. The average age of women was 58.80 +/- 0.94 y. in the first group, 60.36 +/- 5.12 y. in the second group and -61.84 +/- 0.80 y. in the third group. Age, age of menarche, number of childbirths, length of the menstrual cycle and menstrual bleeding, and lumbar bone density were assessed and registered for each woman. We used DXA in a anterior-posterior projection to assess the bone density of the lumbar spine; the obtained results are shown in gram/cm2.

The women from the third group, with average menstrual cycle length of 30 days, reach menopause at a significantly later age, have longer menstrual cycle and shorter menstrual bleeding, and higher lumbar spine bone density, compared to the other two groups.

The data from our research show that women with anamnesis for average normal menstrual cycle length of 30 days reach menopausal period at a significantly later age, have shorter menstrual bleeding, and higher lumbar spine bone density compared to those with shorter menstrual cycle duration (27 and 28 days).