Changes in calcitropic hormones, bone markers and insulin-like growth factor I (IGF-I) during pregnancy and postpartum: a controlled cohort study

TY - JOUR

T1 - Changes in calcitropic hormones, bone markers and insulin-like growth factor I (IGF-I) during pregnancy and postpartum

T2 - a controlled cohort study

AU - Møller, U K

AU - Streym, S

AU - Mosekilde, L

AU - Heickendorff, L

AU - Flyvbjerg, A

AU - Frystyk, J

AU - Jensen, L T

AU - Rejnmark, L

PY - 2013/4

Y1 - 2013/4

N2 - Summary: Pregnancy and lactation cause major changes in calcium homeostasis and bone metabolism. This population-based cohort study presents the physiological changes in biochemical indices of calcium homeostasis and bone metabolism during pregnancy and lactation Introduction: We describe physiological changes in calcium homeostasis, calcitropic hormones and bone metabolism during pregnancy and lactation. Methods: We studied 153 women planning pregnancy (n = 92 conceived) and 52 non-pregnant, age-matched female controls. Samples were collected prior to pregnancy, once each trimester and 2, 16 and 36 weeks postpartum. The controls were followed in parallel. Results: P-estradiol (E2), prolactin and 1,25-dihydroxyvitamin D (1,25(OH)2D) increased (p < 0.001) during pregnancy, whereas plasma levels of parathyroid hormone (P-PTH) and calcitonin decreased (p < 0.01). Insulin-like growth factor I (IGF-I) was suppressed (p < 0.05) in early pregnancy but peaked in the third trimester. Postpartum, E2 was low (p < 0.05); prolactin decreased according to lactation status (p < 0.05). 1,25(OH)2D was normal and IGF-I was again reduced (p < 0.05). P-PTH and calcitonin increased postpartum. From early pregnancy, markers of bone resorption and formation rose and fall, respectively (p < 0.001). From the third trimester, bone formation markers increased in association with IGF-I changes (p < 0.01). Postpartum increases in bone turnover markers were associated with lactation status (p < 0.001). During lactation, plasma phosphate was increased, whereas calcium levels tended to be decreased which may stimulate PTH levels during and after prolonged lactation. Conclusion: The increased calcium requirements in early pregnancy are not completely offset by increased intestinal calcium absorption caused by high 1,25(OH)2D since changes in bone markers indicated a negative bone balance. The rise in bone formation in late pregnancy may be initiated by a spike in IGF-I levels. The high bone turnover in lactating women may be related to high prolactin and PTH levels, low E2 levels and perhaps increased parathyroid hormone-related protein levels.

AB - Summary: Pregnancy and lactation cause major changes in calcium homeostasis and bone metabolism. This population-based cohort study presents the physiological changes in biochemical indices of calcium homeostasis and bone metabolism during pregnancy and lactation Introduction: We describe physiological changes in calcium homeostasis, calcitropic hormones and bone metabolism during pregnancy and lactation. Methods: We studied 153 women planning pregnancy (n = 92 conceived) and 52 non-pregnant, age-matched female controls. Samples were collected prior to pregnancy, once each trimester and 2, 16 and 36 weeks postpartum. The controls were followed in parallel. Results: P-estradiol (E2), prolactin and 1,25-dihydroxyvitamin D (1,25(OH)2D) increased (p < 0.001) during pregnancy, whereas plasma levels of parathyroid hormone (P-PTH) and calcitonin decreased (p < 0.01). Insulin-like growth factor I (IGF-I) was suppressed (p < 0.05) in early pregnancy but peaked in the third trimester. Postpartum, E2 was low (p < 0.05); prolactin decreased according to lactation status (p < 0.05). 1,25(OH)2D was normal and IGF-I was again reduced (p < 0.05). P-PTH and calcitonin increased postpartum. From early pregnancy, markers of bone resorption and formation rose and fall, respectively (p < 0.001). From the third trimester, bone formation markers increased in association with IGF-I changes (p < 0.01). Postpartum increases in bone turnover markers were associated with lactation status (p < 0.001). During lactation, plasma phosphate was increased, whereas calcium levels tended to be decreased which may stimulate PTH levels during and after prolonged lactation. Conclusion: The increased calcium requirements in early pregnancy are not completely offset by increased intestinal calcium absorption caused by high 1,25(OH)2D since changes in bone markers indicated a negative bone balance. The rise in bone formation in late pregnancy may be initiated by a spike in IGF-I levels. The high bone turnover in lactating women may be related to high prolactin and PTH levels, low E2 levels and perhaps increased parathyroid hormone-related protein levels.

KW - Adult

KW - Biomarkers

KW - Bone Remodeling

KW - Bone and Bones

KW - Calcitonin

KW - Calcium

KW - Case-Control Studies

KW - Estradiol

KW - Female

KW - Homeostasis

KW - Hormones

KW - Humans

KW - Insulin-Like Growth Factor I

KW - Lactation

KW - Osteogenesis

KW - Parathyroid Hormone

KW - Postpartum Period

KW - Pregnancy

KW - Prolactin

KW - Vitamin D

KW - Journal Article

KW - Research Support, Non-U.S. Gov't

U2 - 10.1007/s00198-012-2062-2

DO - 10.1007/s00198-012-2062-2

M3 - Journal article

C2 - 22855199

SN - 0937-941X

VL - 24

SP - 1307

EP - 1320

JO - Osteoporosis International

JF - Osteoporosis International

IS - 4

ER -