Size and shape of the pituitary gland during pregnancy and post partum: measurement with MR imaging.
Cranial magnetic resonance (MR) imaging was performed in 38 pregnant and postpartum women and 30 nonpregnant age-matched control subjects to establish standards for pituitary gland size and shape during this period. Gland height and infundibulum width were measured on midline T1-weighted sagittal images. Gland convexity or concavity was graded qualitatively. Throughout pregnancy, gland height increased linearly by approximately 0.08 mm/wk. No gland exceeded 10 mm in height during pregnancy. Increases in gland convexity also correlated with progression of pregnancy. The largest glands were seen in the immediate postpartum period; during this period, five of 12 glands measured 10.0-11.8 mm. Beyond the first week post partum, glands rapidly returned to normal size, apparently regardless of the status of breast-feeding. The mean diameter of the infundibulum was 2.2 mm (range, 0.8-4.0 mm). The pituitary gland enlarges throughout pregnancy but should probably not exceed 10 mm during most of this period. Size of up to 12 mm may be acceptable immediately post partum.
Department of Radiology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1022.
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Chen
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D010902:Pituitary Gland / Q000033:anatomy & histology*; D049590:Postpartum Period; D011247:Pregnancy; D012016:Reference Values