Endocrine Abstracts

Background: Pregnancy and lactation-associated osteoporosis (PLO) is a rare condition that can often be missed by physicians, leading to delayed diagnosis and fractures in young patients. Treatment options include anti-resorptive therapy (bisphosphonates), anabolic therapy (teriparatide), and monoclonal antibody therapy (denosumab), but there is no clear consensus on the best treatment approach. We present two cases outlining the management of PLO.

Case 1: A 28-year-old woman sought medical attention for back pain 4 months postpartum, which she initially attributed to her pregnancy. She had severe hyperemesis gravidarum, requiring high dose prednisolone in second trimester, and was on a vegetarian diet. Although her bone mineral density (BMD) was normal, chest CT that she had for breathlessness showed multi-level compression fractures (T8-T12). The metabolic workup showed 25-OH vitamin D deficiency, 29 (N-50-120nmol/l) and elevated bone turnover markers, CTX, 0.56 (N-0.10-0.50µg/l) and P1NP, 151 (N-19-69µg/l). Following vitamin D replacement, a three-year course of zoledronate infusion was commenced.

Case 2: A 35-year-old woman, 11 months postpartum, sustained a low-trauma wrist fracture. She had been breastfeeding but had no other osteoporosis risk factors. BMD showed lumbar and hip T scores of -3.3 and -3.2, respectively, with elevated P1NP, 74 (N-19-69µg/l) and low oestradiol level, <92 pmol/l. She was advised to stop breastfeeding and was given a two-year course of teriparatide followed by a single zoledronate infusion. Post-treatment BMD showed significant improvement with no further fractures. The genetic test result for Osteogenesis Imperfecta is pending.

Conclusion: PLO has a complex pathophysiology, causing increased bone loss due to increased PTHrP, calcium secretion during breastfeeding, and suppression of the hypothalamic-pituitary-ovarian axis, leading to low oestrogen. Although BMD may recover in 12-18 months, early diagnosis and ruling out secondary causes are crucial for reducing fracture risk.

Discussion: Further evaluation of PLO treatment effectiveness, duration, and long-term outcomes is needed.