[Osteoporosis during pregnancy and lactation].
During pregnancy and lactation women have to form and maintain fetus and newborn skeleton. These processes require maternal hormonal and metabolic adjustments. During the first weeks of pregnancy, calcium intestinal absorption rise and reach a maximum in the last trimester. Hypercalciuria can be detected until lactation is stopped. During lactation, calcium that is present in maternal milk, results from lowering maternal calcium excretion and increasing bone resorption. Plasma 1,25 (OH)(2) D(3) levels increase two-fold early in pregnancy due to high placental 1-alpha-hydroxilase activity, remain high until delivery and decline to normal values during lactation. Estrogen, prolactin and placental lactogen, which are involved in calcium absorption, increase at the same time. Normal or even low levels of parathyroid hormone (PTH) can be detected during pregnancy. This suggests that their physiological actions could be mimicked by the parathyroid- related-peptide (PTHrP), which increases in late stages of pregnancy and remain high during delivery and lactation. Calcitonin levels increase during pregnancy, decline during lactation and return to normal values after lactation is stopped. The physiological roll of tumor necrosis factor, interleukin 6 and osteoprotegerin has not been elucidated yet. The above mentioned changes can exceptionally lead to generalized or regional osteoporosis. The aim of this article is to review the published bibliography concerning the physiopathology of these diseases.
Sarli
Marcelo
M
Instituto de Investigaciones Metabólicas, Universidad del Salvador, Buenos Aires. msarli@yahoo.com
Hakim
Carina
C
Rey
Paula
P
Zanchetta
José
J
D015502:Absorptiometry, Photon; D000328:Adult; D015519:Bone Density / Q000502:physiology; D001862:Bone Resorption / Q000209:etiology / Q000378:metabolism; D002118:Calcium / Q000378:metabolism / Q000627:therapeutic use; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology; D007774:Lactation / Q000378:metabolism* / Q000502:physiology; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D014807:Vitamin D / Q000378:metabolism / Q000627:therapeutic use
D010281:Parathyroid Hormone; D014807:Vitamin D; D010758:Phosphorus; D002118:Calcium