Sarli Marcelo, Hakim Carina, Rey Paula, Zanchetta José
Instituto de Investigaciones Metabólicas, Universidad del Salvador, Buenos Aires.
Medicina (B Aires). 2005;65(6):533-40.
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.
在怀孕和哺乳期间，女性必须形成并维持胎儿和新生儿的骨骼。这些过程需要母体进行激素和代谢调整。在怀孕的前几周，肠道对钙的吸收增加，并在妊娠晚期达到最大值。高钙尿症在哺乳期结束前都可检测到。在哺乳期间，母乳中的钙来自母体钙排泄的减少和骨吸收的增加。由于胎盘1-α-羟化酶活性高，血浆1,25(OH)₂D₃水平在怀孕早期增加两倍，直到分娩前一直保持高水平，在哺乳期降至正常值。参与钙吸收的雌激素、催乳素和胎盘催乳素同时增加。在怀孕期间可检测到甲状旁腺激素(PTH)水平正常甚至偏低。这表明其生理作用可能被甲状旁腺相关肽(PTHrP)模拟，后者在怀孕后期增加，并在分娩和哺乳期间保持高水平。降钙素水平在怀孕期间升高，在哺乳期下降，哺乳期结束后恢复到正常值。肿瘤坏死因子、白细胞介素6和骨保护素的生理作用尚未阐明。上述变化偶尔会导致全身性或局部骨质疏松。本文的目的是回顾已发表的有关这些疾病病理生理学的文献。
