Bone Density After Teriparatide Discontinuation With or Without Antiresorptive Therapy in Pregnancy- and Lactation-Associated Osteoporosis

Current and future perspectives on pregnancy and lactation-associated osteoporosis

Normal pregnancy and lactation have a marked physiological impact on maternal bone metabolism. This impact is usually temporary and reversible, but some women sustain fragility fractures whilst pregnant or lactating, termed pregnancy and lactation-associated osteoporosis (PLO). These fractures have severe negative consequences on their quality of life, at what is a crucial stage in a mother's life. Identifiable risk factors include a low body mass index (BMI), reduced physical activity during adolescence, a strong family history of osteoporosis, and genetic variations in the LRP5 and WNT1 genes. However, due to the rarity of PLO and the limited awareness surrounding it, there has been slow progress in understanding its pathophysiology and identifying the most effective treatments. Indeed, the data available primarily originates from observational and case studies, resulting in little clear guidance on a comprehensive and multidisciplinary approach. This mini-review synthesises the latest data on incidence, pathophysiology, and management in PLO, providing current and future perspectives and highlights the need for evidence-based guidelines to improve both short-term and long-term outcomes for women with PLO.

Effective strategies for pregnancy and lactation-associated osteoporosis: teriparatide use in focus

INTRODUCTION

Pregnancy and lactation-associated osteoporosis (PLO) is a rare condition characterized by fragility fractures occurring during late pregnancy or lactation, primarily affecting the spine and causing significant morbidity and back pain. PLO can lead to mobility impairment and work incapacity, with recovery taking up to several years. Due to the lack of clinical trials, treatment strategies remain poorly defined, historically focusing on calcium supplements, vitamin D, and weaning from breastfeeding. However, recent attention has turned to teriparatide (TPD) as an option due to its anabolic properties and potential suitability for women of childbearing age.

METHODS

This review evaluates TPD's use in PLO treatment, using published systematic reviews and case studies. Over 300 cases with PLO were identified through PubMed, Google Scholar, and Cochrane searches until August 2023.

RESULTS

We identified 175 cases with PLO treated with TPD alone or followed by antiresorptive therapy. Most women (85.7%) were primiparas. The mean ± SD duration of TPD use was 15 ± 6 months. Among the study patients, 91.4% used TPD alone, while 8.6% (15/175) utilized sequential therapy. Approximately 93% of our cohort exhibited potential risk factors for PLO. Despite the increased risk of recurrent fractures in PLO, only 14.7% (20/175) of those treated with TPD sustained new fractures during a 9-month to 9 years' follow-up period. The mean ± SD percent increase in BMD at the LS was 21.14% ± 7.4%, and at the FN it was 12.1% ± 9.3%. The baseline Z-scores at the LS ranged from -3.3 (-3.7 to -2.7), while the baseline Z-scores at the FN ranged from -2.0 (-2.7 to -1.5).

CONCLUSION

This review emphasizes PLO severity, advocating for increased awareness and timely interventions. TPD emerges as a promising therapeutic option in certain cases.

Bone Metabolism, Bone Mass, and Bone Structure During Pregnancy and Lactation: Normal Physiology and Pregnancy and Lactation-Associated Osteoporosis

This article reviews bone metabolism, bone mass, and bone structure changes expected during and after pregnancy and lactation, as well as the condition of pregnancy and lactation-associated osteoporosis (PLO)-a presentation with fragility fracture(s) in the context of these physiologic changes. Clinical implications of physiologic bone changes will be addressed, as will specific management considerations that apply to premenopausal women with PLO.

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.

Crosstalk within a brain-breast-bone axis regulates mineral and skeletal metabolism during lactation

To support the increased calcium demands for milk production during lactation, a dramatic and reversible physiological response occurs to alter bone and mineral metabolism. This coordinated process involves a brain-breast-bone axis that integrates hormonal signals that allow for adequate calcium delivery to milk yet also protects the maternal skeletal from excessive bone loss or decreases in bone quality or function. Here, we review the current knowledge on the crosstalk between the hypothalamus, mammary gland, and skeleton during lactation. We discuss the rare entity of pregnancy and lactation associated osteoporosis and consider how the physiology of bone turnover in lactation may impact the pathophysiology of postmenopausal osteoporosis. Further understanding of the regulators of bone loss during lactation, particularly in humans, may provide insights into new therapies for osteoporosis and other diseases of excess bone loss.

Bone Microarchitecture and Strength Changes During Teriparatide and Zoledronic Acid Treatment in a Patient with Pregnancy and Lactation-Associated Osteoporosis with Multiple Vertebral Fractures

Pregnancy- and lactation-associated osteoporosis (PLO) is a rare form of osteoporosis, of which the pathogenesis and best treatment options are unclear. In this report, we describe the case of a 34-year old woman diagnosed with severe osteoporosis and multiple vertebral fractures after her first pregnancy, who was subsequently treated with teriparatide (TPTD) and zoledronic acid (ZA). We describe the clinical features, imaging examination, and genetic analysis. Substantial improvements were observed in areal and volumetric bone mineral density (BMD), microarchitecture, and strength between 7 and 40 months postpartum as assessed by dual-energy X-ray absorptiometry at the total hip and spine and by high-resolution peripheral quantitative CT at the distal radius and tibiae. At the hip, spine, and distal radius, these improvements were mainly enabled by treatment with TPTD and ZA, while at the distal tibiae, physiological recovery and postpartum physiotherapy due to leg pain after stumbling may have played a major role. Additionally, the findings show that, despite the improvements, BMD, microarchitecture, and strength remained severely impaired in comparison with healthy age- and gender-matched controls at 40 months postpartum. Genetic analysis showed no monogenic cause for osteoporosis, and it is suggested that PLO in this woman could have a polygenic origin with possible susceptibility based on familiar occurrence of osteoporosis.

Effect of Teriparatide on Subsequent Fracture and Bone Mineral Density in 47 Women with Pregnancy- and Lactation-associated Osteoporosis and Vertebral Fractures

Introduction Pregnancy- and lactation-associated osteoporosis (PLO) with predominantly vertebral fractures is a rare but severe disease which can occur in the last trimester of pregnancy or postpartum. The aim of the present study was to assess the impact of teriparatide on subsequent fractures and bone mineral density (BMD) in patients with PLO.

Materials and Methods A total of 47 patients with PLO and postpartum spinal fractures (mean: 4 fractures) undergoing treatment with teriparatide were investigated. The data collection period was set between 2006 and 2018. All patients received a subcutaneous injection of 20 µg teriparatide once a day for 24 months as well as individually adapted vitamin D supplementation. After 24 months of treatment, all women received no further treatment and either had regular menstrual cycles or took oral contraceptives. Fractures were confirmed by X-ray or MRI. Changes in BMD from baseline were examined using serial DXA measurements.

Results After 24 months of teriparatide treatment, we could demonstrate an increase in BMD at the lumbar spine, femoral neck and total hip of + 30.1%, + 11.7% and + 12.2% respectively (p < 0.001 for all). At 12 months after cessation of treatment, BMD remained stable compared to the 24-month measurements at the lumbar spine, femoral neck and total hip which showed non-significant changes of + 1.4%, + 2.6% and + 4.1% respectively. Out of the 47 patients with PLO with a mean of 4 existing fractures, 4 patients (7.8%) sustained a subsequent fracture, two after 3 – 5 months of treatment and two at > 6 months of treatment.

Conclusion 24 months of treatment with teriparatide in women with PLO and multiple vertebral fractures significantly increased BMD, predominantly BMD of the spine. As patients were premenopausal, there was no significant decrease in BMD in the following 12 months after cessation of treatment.

Dilemmas in the Management of Osteoporosis in Younger Adults

Osteoporosis in premenopausal women and men younger than 50 years is challenging to diagnose and treat. There are many barriers to optimal management of osteoporosis in younger adults, further enhanced by a limited research focus on this cohort. Herein we describe dilemmas commonly encountered in diagnosis, investigation, and management of osteoporosis in younger adults. We also provide a suggested framework, based on the limited available evidence and supported by clinical experience, for the diagnosis, assessment, and management of osteoporosis in this cohort. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.