Renee, I have no experience with this condition but was intrigued as I know that the absence of PTHrP (parathyroid hormone related protein) is related to problems with ductal branching during pregnancy. Here is what I've found in Medline regarding hypoparathyroidism; surprisingly, it sounds a bit like diabetes management during lactation only calcium supplementation is the issue at hand: ~Lisa Marasco ---------------------- J Bone Miner Res. 1990 Jan;5(1):69-75. Related Articles, Links Parathyroid hormone is not required for normal milk composition or secretion or lactation-associated bone loss in normocalcemic rats. Garner SC, Boass A, Toverud SU. Department of Pharmacology, University of North Carolina, Chapel Hill 27599-7455. To determine if parathyroid hormone (PTH) is essential for lactation in rats, the parathyroid glands were removed surgically during the first week of lactation and the rats were given a diet containing a high calcium-phosphorus ratio to maintain a normal serum calcium concentration. Lactating rats were placed on diet containing 1.2% calcium (Ca) and 0.8, 0.6, or 0.4% phosphorus (P) on day 2 postpartum (PP) and were parathyroidectomized (PTX) at 4-6 days PP. At 10 days PP serum Ca was 10.5 +/- 0.2 mg/dl (mean +/- SEM) for PTX rats and 10.4 +/- 0.3 mg/dl in sham-operated lactating rats when the diet contained 0.6% P. When the diet P was 0.8%, the litters gained little or no weight and serum Ca fell to 6.9 +/- 0.6 mg/dl by day 10 PP in PTX rats compared with 10.2 +/- 0.2 mg/dl in sham rats. PTX rats fed the diet containing 1.2% Ca and 0.6% P maintained a normal serum Ca level until at least day 18 PP, but their serum P levels fell gradually from approximately 5 mg/dl at 10 days to 3 mg/dl at 18 days PP. In spite of this hypophosphatemia, the litters of PTX and sham rats had gained the same amount of weight by age 16 days, indicating equal milk production in the two groups. Milk Ca, P, and total solids were not significantly different between PTX and sham rats on day 11 PP.(ABSTRACT TRUNCATED AT 250 WORDS) --------------------------------------------------- Clin Endocrinol (Oxf). 1987 Jun;26(6):667-74. Related Articles, Links Remission of hypoparathyroidism during lactation: evidence for a physiological role for prolactin in the regulation of vitamin D metabolism. Cundy T, Haining SA, Guilland-Cumming DF, Butler J, Kanis JA. Department of Medicine, King's College School of Medicine and Dentistry, London, UK. We studied a young woman with surgical hypoparathyroidism who, on her usual maintenance dose of calcitriol, developed hypercalcaemia 9 d postpartum when lactation was established. Serum values of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) values were very high (127 pg/ml). The patient remained without exogenous calcitriol treatment for 40 d, during which time serum 1,25(OH)2D3 levels remained within the normal range and serum calcium fell with a half-time of 27 d. The requirements for calcitriol increased to antepartum levels when lactation had ceased. There was a close negative correlation between requirements for calcitriol and serum PRL values. After weaning, an episode of hypercalcaemia was induced by increasing the dose of calcitriol. On stopping calcitriol the serum 1,25(OH)2D3 fell to low values (4 pg/ml) within 2 d and serum calcium fell with a half-time of 3 d, necessitating the early reintroduction of calcitriol. We conclude that in hypoparathyroidism exogenous vitamin D requirements fall during lactation because of enhanced endogenous production of 1,25(OH)2D3. The lactation-associated increase in circulating 1,25(OH)2D3 concentrations thus results from a parathyroid hormone-independent mechanism, possibly by an effect of PRL on the 1 alpha-hydroxylase. ----------------------------------------------- J Reprod Med. 1993 Nov;38(11):914-8. Related Articles, Links Reduced calcitriol requirements for treating hypoparathyroidism during lactation. A case report. Caplan RH, Wickus GG. Department of Internal Medicine, Gundersen/Lutheran Medical Center, La Crosse, Wisconsin. We reduced the dose of calcitriol from 0.75 to 0.25 microgram/d to maintain low normal serum calcium levels in a hypoparathyroid woman during lactation. Calcitriol requirements quickly returned to 0.75 microgram/d when she discontinued breast-feeding. In her previous pregnancy, failure to reduce the dose of calcitriol resulted in serious hypercalcemia 11 days after she began breast-feeding. The changing requirement for calcitriol in our patient related directly to the falling level of estradiol. Although the cause or causes of diminished calcitriol requirements in hypoparathyroid women during lactation remains unclear, increased bone resorption promoted by low plasma estrogen levels may be an important mechanism. We conclude that the dose of calcitriol should be reduced during lactation and that both the hypoparathyroid mother and her infant should be carefully monitored to detect abnormal serum calcium levels. -------------------------------------------- Endocrinol Jpn. 1984 Jun;31(3):227-33. Related Articles, Links Postpartum resolution of hypocalcemia in a lactating hypoparathyroid patient. Rude RK, Haussler MR, Singer FR. A 24 year old woman with post-surgical hypoparathyroidism was studied during pregnancy and lactation. During pregnancy the patient required less vitamin D therapy for control of her hypoparathyroidism and, while lactating, maintained a normal serum calcium without any supplemental vitamin D. The serum parathyroid hormone concentration and plasma 1,25 (OH)2 vitamin D concentration were undetectable and low normal respectively at a time when the serum calcium concentration was normal and the patient was not on vitamin D therapy. Urinary calcium excretion was low during this period and may explain the normalization of the serum calcium. The mechanism by which the improvement in calcium metabolism occurred is unknown, but may be secondary to a direct effect of prolactin on calcium homeostasis. *********************************************** To temporarily stop your subscription: set lactnet nomail To start it again: set lactnet mail (or digest) To unsubscribe: unsubscribe lactnet All commands go to [log in to unmask] The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(R) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html