Pregnancy-and lactation-associated osteoporosis with multiple vertebral compression fractures in an adolescent primipara: A case report

Abstract

Background: Pregnancy and lactation-associated osteoporosis (PLO) is a rare but potentially disabling cause of osteoporosis that typically presents during late pregnancy or the early postpartum period with severe back pain secondary to vertebral compression fractures. Owing to its rarity and nonspecific presentation, diagnosis is frequently delayed, and secondary causes of osteoporosis must be carefully excluded.

Case summary: A 19-year-old primiparous woman presented to us, 4.5 months after delivery with progressively worsening thoracolumbar back pain that had started two weeks postpartum. She had undergone lower uterine cesarean section at 38+ weeks' gestation and delivered a healthy 2.7-kg infant. During pregnancy, she gained approximately 22 kg and received calcium supplementation (500 mg/day) without vitamin D supplementation. The patient was strongly advised for discontinuing breast feeding because it removes the primary driver of elevated mammary-derived PTHrP and hypoestrogenic hyper-resorption, arresting maternal bone density loss. X-ray Dorso-lumber spine showed mild body height reduction in 11th and 12th thoracic vertebrae. Dual-energy X-ray absorptiometry revealed severe osteoporosis with a lumbar spine bone mineral density of 0.554 g/cm² (Z-score −5.0). Magnetic resonance imaging demonstrated multiple thoracic and lumbar vertebral compression fractures. Laboratory investigations showed normal serum calcium, phosphate, alkaline phosphatase, thyroid function, morning cortisol, parathyroid hormone (45.7 pg/mL), and 25-hydroxyvitamin D (32.6 ng/mL). Autoimmune screening, celiac serology, and serum protein electrophoresis were unremarkable. The patient was managed with daily subcutaneous teriparatide injections along with cessation of breastfeeding, calcium supplementation, and vitamin D₃ (40,000 IU weekly for five weeks followed by 1,000 IU daily).

Conclusion: This case highlights that pregnancy and lactation-associated osteoporosis may occur in adolescents and present shortly after delivery despite normal calcium-phosphate metabolism and the absence of prolonged lactation or other identifiable secondary causes of osteoporosis. Early recognition, comprehensive exclusion of secondary etiologies, prompt discontinuation of breastfeeding, and appropriate calcium and vitamin D supplementation are essential to optimize recovery and prevent further fractures.

[J Assoc Clin Endocrinol Diabetol Bangladesh, 2026;5(Suppl 1): S58]