Pregnancy- and lactation-associated vertebral compression fractures: MRI prevalence and characteristics

Complex clinical encounter series: osteoporosis presenting during pregnancy and lactation: wait and reassess

Two months after her first pregnancy, a 35-yr-old exclusively breastfeeding woman bent to move her baby in the car seat and experienced sudden, severe pain from 5 spontaneous vertebral compression fractures. Genomic screen was negative but she had mild ankylosing spondylitis previously well controlled on etanercept. She was vegetarian with a high phytate intake. A lactation consultant had advised her to pump and discard milk between feeds, leading her to believe she produced twice as much milk as her baby ingested. She presented with a LS Z score of -3.6 and a TH Z score of -1.6. After 6 mo postweaning, she was treated with teriparatide (14 mo intermittently over 18 mo) and ultimately achieved a 50% increase in LS bone density and an 8% increase in TH bone density. Her fragility is explained by normal lactational bone loss amplified by excessive milk production and phytate-induced impairment of intestinal calcium absorption, ankylosing spondylitis, and the bend-and-lift maneuver. The marked increase in bone density resulted from the combined effects of spontaneous recovery and pharmacotherapy. Spontaneous recovery of bone mass and strength should occur during 12 mo after weaning in all women, including those who have fractured.

Proceedings of the 2023 Santa Fe Bone Symposium: Progress and Controversies in the Management of Patients with Skeletal Diseases

The Santa Fe Bone Symposium (SFBS) held its 23rd annual event on August 5-6, 2023, in Santa Fe, New Mexico, USA. Attendees participated in-person and remotely, representing many states and countries. The program included plenary presentations, panel discussions, satellite symposia, a Project ECHO workshop, and a session on healthcare policy and reimbursement for fracture liaison programs. A broad range of topics were addressed, including transitions of osteoporosis treatments over a lifetime; controversies in vitamin D; update on Official Positions of the International Society for Clinical Densitometry; spine surgery and bone health; clinical applications of bone turnover markers; basic bone biology for clinicians; premenopausal-, pregnancy-, and lactation-associated osteoporosis; cancer treatment induced bone loss in patients with breast cancer and prostate cancer; genetic testing for skeletal diseases; and an update on nutrition and bone health. There were also sessions on rare bone diseases, including managing patients with hypophosphatasia; treatment of X-linked hypophosphatemia; and assessment and treatment of patients with hypoparathyroidism. There were oral presentations of abstracts by endocrinology fellows selected from those who participated in the Santa Fe Fellows Workshop on Metabolic Bone Diseases, held the 2 days prior to the SFBS. These proceedings of the 2023 SFBS present the clinical highlights and insights generated from many formal and informal discussions in Santa Fe.

Recent Insights into Pregnancy and Lactation-Associated Osteoporosis (PLO)

During pregnancy and lactation, female physiology adapts to fulfill the fetal and neonatal calcium and phosphorus requirements. The physiological changes that take place during these periods do not affect maternal skeleton resistance to fracture in most of the cases. However, there is a small percentage of women that do experience fragility fractures during these times of life. Pregnancy and lactation-associated osteoporosis (PLO) is an infrequent condition defined by the occurrence of non-traumatic fractures - most frequently vertebral - during the third trimester of gestation and/or the first months of postpartum. Its physiopathology has not yet been completely elucidated. Several authors have reported that risk factors for secondary osteoporosis might be present in up to 80% of the cases of PLO patients. According to recent studies, genetic factors might also play a relevant role in PLO. Given its rarity, the available literature on this condition is limited. Most of the published data consist on case reports and case series articles. There are not any randomized controlled trials regarding this disorder. Although there is consensus about discontinuation of lactation and calcium and vitamin D supplementation as the first steps in the treatment of these patients, there is still controversy regarding the long-term and/or pharmacological management of this condition. Recent data on the use of teriparatide in this population looks promising. In this review, we aimed to revise and summarize current knowledge about the physiopathology and management of PLO.

Bridging the Gap: Pregnancy-And Lactation-Associated Osteoporosis

Early diagnosis of pregnancy- and lactation-associated osteoporosis (PLO) is mandatory for a good outcome. Standard care is not a matter of conventional guidelines, rather it requires an individualized strategy while true overall incidence and pathogeny remain open issues. This is a narrative review based on full-length English articles, published between January 2021 and March 2023 and accessed via PubMed (no traumatic fractures or secondary osteoporosis are included). Our case-sample-based analysis included 836 females with PLO (the largest cohort based on published cases so far) through 12 studies and 24 single case reports. Except for one survey, these involved retrospective cohorts of small size (6-10 females/study) to medium size (23-47 women/study), and large cohorts with >50 subjects per study (a maximum of 379). Age of diagnosis: from 24 to 40 years for case reports (most subjects being over 30 and primigravida), while original studies indicated an average age between 31 and 34.18 years. Type of fractures underlined a most frequent vertebral phenotype (a mean of 2 to 5.8 vertebral fractures per patient) versus a most severe non-vertebral phenotype (hip and femoral neck fractures mostly requiring surgery). Potential contributors varied: smoking (1/3-1/2 of subjects), family history of osteoporosis (1/3), heparin and glucocorticoid use in pregnancy, low body mass index (majority of cases), hypovitaminosis D; and (with a low level of statistical significance) anti-psychotic medication, gestational diabetes, lupus, thrombophilia, anemia, in vitro fertilization (1/3 in one study), twin pregnancy, tocolysis with MgSO4, and postpartum thyroiditis. Most remarkably, up to 50% of PLO patients harbor mutations of LRP5, WNT1, and COL1A1/A2 (more damaged form with potential benefits from osteoanabolic drugs); gene testing might become the new norm in PLO. The low index of clinical suspicion should be supported by performing magnetic resonance imaging (gold standard in pregnancy) with DXA (in lactation). Low bone mineral density is expected (Z-score varying from -2.2 SD to -4 SD, unless normal which does not exclude PLO). Bone turnover markers might be useful in individuals with normal DXA, in pregnancy when DXA cannot be performed, and in following the response to anti-osteoporosis drugs. Alternatively, microarchitecture damage might be reflected by DXA-trabecular bone score and high-resolution peripheral quantitative computed tomography. Specific medical interventions are currently focused on teriparatide (TPT) use (3 studies; n = 99 females treated with TPT and an additional subgroup of 18 patients from the gene-analysis-based study, thus a total of 117 females) which seems to be the therapy of choice as reflected by these new data: 6-24 months, 20 µg/day, no sequential therapy needed; case selection based on high fracture risk is necessary). The first case using romosozumab was reported in 2022. PAO/LAO remains a challenging condition which is a battle for the wellbeing of two individuals, on one hand, considering maternal-fetal outcomes and taking care of the offspring, but it is a battle for a multidisciplinary team, on the other hand, since a standardized approach is lacking.

Bone metabolism and osteoporosis during pregnancy and lactation

PURPOSE

Osteoporosis in pregnancy is an uncommon disease and there is little information regarding its pathogenesis and its effects on the skeleton. This review aims to describe changes in mineral metabolism during pregnancy and lactation as well as their clinical impact.

METHODS

We performed a narrative review of the literature using the PubMed and Google Scholar databases for articles published from 1955 to 2021.

RESULTS

Mineral metabolism in the mother must adapt to the demand created by the fetus and the placenta, which together absorb calcium and other minerals from the mother to mineralize the developing fetal skeleton; analyses of iliac bone biopsies at the beginning and end of pregnancy have shown that pregnancy significantly modifies maternal bone status. The greatest demand for calcium for the maternal skeleton occurs during lactation; women who breastfeed have an even greater loss of calcium to produce milk. However, it is controversial whether breastfeeding can increase the risk of osteoporotic fractures, and the possible mechanism is considerably complicated. Osteoporosis in pregnancy is an uncommon disease characterized by the occurrence of fragility fractures, most commonly in the vertebral column, in the third trimester of pregnancy, or early postpartum. The pathogenesis of PLO remains unclear owing to its rarity; DXA provides a sensitive and specific method for diagnosing osteoporosis by measuring BMD, one of the parameters that allow a better understanding of fracture risk. One limitation is the controversy in using radiation in pregnant women and the risk to the embryo/fetus; a safe alternative can be MRI.

CONCLUSION

Pregnancy and lactation alter the maternal bone status; without a balance in metabolism, this may cause an increased risk of fracture due to changes in BMD. There is little information on BMD during pregnancy; more clinical studies are required to elucidate if this represents a risk factor for osteoporosis.