Category: Calcium/Bone Disorders
Discuss the clinical presentation of pregnancy and lactation induced osteoporosis.
Methods : Case report
A 30 years old female presented with mid-back pain that started about three months after she gave birth and while breastfeeding. Imaging showed an acute T7 vertebral compression fracture. A month later, she sustained a mild compression fracture of T4. The first fracture occurred as she was lifting a three-year old child and the second while twisting her torso. Dual energy absorptiometry (DXA) showed a Z score of -2.6 at L1-L4 and -2.8 at the left femoral neck. She had a 25 hydroxyvitamin D level of 25 ng/ml (normal 20-80) and a serum calcium of 10.1 mg/dL (normal 8.5-10.5). The patient was taking 1,200mg of calcium daily and 800 Units of Vitamin D daily. The diagnosis of lactation-induced osteoporosis was made and the patient was advised to stop breastfeeding, increase vitamin D intake to 2000 units daily, avoid bending and twisting movements of her spine, and to repeat DXA a year later.
Pregnancy and lactation induced osteoporosis is a rare condition. It is attributed to hormonal changes that favor transfer of calcium from the mother to the fetus during pregnancy and for production of breast milk during lactation. During lactation, there is increased production of parathyroid hormone-related peptide (PTH-rp) from breast tissue, aiming to mobilize calcium from the mother’s skeleton to increase milk production. This is coupled with an elevated prolactin that leads to low estrogen production also favoring bone resorption. There is up to 3-9% mineral loss at the spine during the first 3-6 months of lactation and some patients may experience vertebral compression fractures during that period of time.
Conclusion : The most important intervention to prevent recurrent fractures is to stop breastfeeding, which will lead to normalization of PTH-rp, prolactin and estrogen and will allow the mother to regain most or all of the lost bone mineral within 12-24 months of stopping lactation.
University of Iowa Hospitals and Clinics
Iowa City, Iowa
Dr. Adeyinka Taiwo is an Endocrine Fellow at the University of Iowa.