Female pituitary size in relation to age and hormonal factors

Background: It is well known that pituitary volume decreases with age; little is known about the influences of female cycle, intake of oral contraceptives, number of given births and duration of menopause on pituitary morphology. Furthermore, these contexts have never been examined with 3-tesla MRI, from which a high spatial resolution is expected. Methods: Ninety-four women from 18 to 80 years (mean 64 years) had to answer a questionnaire concerning their cycle situation, menopause, hormone intake and childbirths before receiving a 3-tesla MRI scan (Achieva, Philips, N.V.), including a T ₁-weighted TSE sequence of the sella turcica. Pituitary volumes and diameters were measured with the software iplan® (BrainLAB, Feldkirchen, Germany). Results: A significant reverse correlation was found between age and pituitary volume (p < 0.0001)/cranio-caudal diameter (p = 0.02). In addition, an age-independent influence of oral contraceptives was found, indicating smaller pituitary sizes with hormone intake (p = 0.003). Cycle phase, number of given births and onset or duration of menopause had no effects on pituitary size. Conclusion: Three-tesla MRI suggests that pituitary volume not only decreases with age, it also seems to be related to long-term hormonal changes such as intake of oral contraceptives.