Pregnancy and Lactation-Associated Osteoporosis: Bone Histomorphometric Analysis and Response to Treatment with Zoledronic Acid

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.

Low serum lipase levels in mothers of children with stunted growth indicate the possibility of low calcium absorption during pregnancy: A cross-sectional study in North Sumatra, Indonesia

Stunting is caused by various factors, including low nutritional intake in the first two years of life. This study aimed to investigate the differences in sociodemographic factors and mineral, vitamin, and enzyme parameters in mothers associated with the occurrence of stunting in children. We conducted a cross-sectional study from September to November 2020 on North Sumatra Island, Indonesia. The data collected included sociodemographic characteristics, pregnancy history, birth history, food intake, and laboratory examinations, including measurements of calcium, iron, zinc, vitamin D, pancreatic amylase, and serum lipase levels. This study included 50 healthy mothers aged 18-50 years old with children aged 2 to 60 months. There was a significant difference in serum calcium levels between the groups of mothers of children with normal and stunted growth (p = 0.03, mean difference±standard error (SE) = 0.23±0.12, 95% CI: 0.19-0.45). All of the study subjects were categorized as vitamin D deficient. The mean lipase level in the group of mothers of children with stunted growth was significantly lower than that in the group of mothers of children with normal growth (p = 0.02, mean difference±SE = 4.34±1.83, 95% CI: 0.62-8.06). The conclusion was that serum lipase levels were significantly lower in mothers of children with stunted growth compared to mothers of children with normal growth. Serum lipase levels this low are likely to indicate that a mother is unable to meet her child's calcium needs during pregnancy, increasing the child's risk of stunted growth.

Comparative Effectiveness of Therapeutic Interventions in Pregnancy and Lactation-Associated Osteoporosis: A Systematic Review and Meta-analysis

CONTEXT

The optimal management of pregnancy and lactation-associated osteoporosis (PLO) has not been designated.

OBJECTIVE

To systematically review the best available evidence regarding the effect of different therapeutic interventions on bone mineral density (BMD) and risk of fractures in these patients.

METHODS

A comprehensive search was conducted in PubMed/Scopus databases until December 20, 2022. Data were expressed as weighted mean difference (WMD) with 95% CI. The I2 index was employed for heterogeneity. Studies conducted in women with PLO who received any antiosteoporosis therapy were included. Studies including women with secondary causes of osteoporosis or with transient osteoporosis of the hip were excluded. Data extraction was independently completed by 2 researchers.

RESULTS

Sixty-six studies were included in the qualitative analysis (n = 451 [follow-up time range 6-264 months; age range 19-42 years]). The increase in lumbar spine (LS) BMD with calcium/vitamin D (CaD), bisphosphonates, and teriparatide was 2.0% to 7.5%, 5.0% to 41.5%, and 8.0% to 24.4% at 12 months, and 11.0% to 12.2%, 10.2% to 171.9%, and 24.1% to 32.9% at 24 months, respectively. Femoral neck (FN) BMD increased by 6.1% with CaD, and by 0.7% to 18% and 8.4% to 18.6% with bisphosphonates and teriparatide (18-24 months), respectively. Meta-analysis was performed for 2 interventional studies only. Teriparatide induced a greater increase in LS and FN BMD than CaD (WMD 11.5%, 95% CI 4.9-18.0%, I2 50.9%, and 5.4%, 95% CI 1.2-9.6%, I2 8.1%, respectively).

CONCLUSION

Due to high heterogeneity and lack of robust comparative data, no safe conclusions can be made regarding the optimal therapeutic intervention in women with PLO.

Clinical Features, Incidence and Treatment Outcome in Pregnancy-Associated Osteoporosis: A Single-Centre Experience over Two Decades

Pregnancy-associated osteoporosis (PAO) is a rare syndrome which typically presents with vertebral fractures during pregnancy or lactation. The medical records of sixteen patients with PAO who presented to a specialist clinic at the Western General Hospital in Edinburgh over a 20-year period were reviewed to evaluate the mode of presentation, potential risk factors and response to treatment. The most common presentation was back pain occurring in 13/16 (81.2%) individuals due to multiple vertebral fractures. The diagnosis was usually made postpartum and in 12/16 individuals (75.0%), PAO presented during the woman's first pregnancy. Medicines which could have contributed to the development of PAO included thromboprophylaxis therapies in 8 subjects (50.0%), inhaled or injected corticosteroids in 5 (31.3%), anticonvulsants in 2 (12.5%) and a LHRH agonist in 1 (6.3%). Five individuals reported a family history of osteoporosis, and two pregnancies were complicated by hyperemesis gravidarum. Treatments administered included calcium and vitamin D supplements, bisphosphonates and teriparatide. Bone mineral density increased following the diagnosis in all cases, regardless of treatment given. One patient had further fracture during follow-up, but four patients had subsequent pregnancies without fractures. We estimated that in this locality, the incidence of PAO was 6.8/100,000 pregnancies with a point prevalence of 4.1 per 100,000 women. This case series indicates the importance of family history of osteoporosis and thromboprophylaxis drugs as risk factors for PAO while also demonstrating that the reductions in bone density tend to reverse with time, irrespective of the treatment given.

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.

Fractures within 2 years of an obstetric hospitalization: analysis of nationwide administrative data in Japan

INTRODUCTION

Pregnancy- and lactation-associated osteoporosis (PLO) is a condition in which young women develop fractures during pregnancy or breastfeeding. Though PLO is a severely debilitating disease, its pathophysiology and epidemiology have not been clarified and its treatment has not been established. We aimed to identify the incidence and factors associated with fractures occurring within 2 years following an obstetric hospitalization.

MATERIALS AND METHODS

We extracted data on fractures occurring within 2 years of an obstetric hospitalization from the Japanese Diagnosis Procedure Combination database. We analyzed the implementation of bone mineral density and bone metabolism marker tests, prescription status, and factors associated with fractures occurring within 2 years of an obstetric hospitalization.

RESULTS

Among 837,347 patients with a history of obstetric hospitalization from 2010 to 2014, 379 patients had a history of hospitalization due to a fracture occurring within 2 years (4.5/10,000 pregnancies). Among the patients with fractures occurring within 2 years of an obstetric hospitalization, 6.7% underwent bone mineral quantification or a bone metabolism marker test, and 7.5% were prescribed a lactation inhibitor or osteoporosis treatment. Factors associated with fractures occurring within 2 years following an obstetric hospitalization identified included Cushing syndrome, Charlson Comorbidity Index score ≥ 1, age ≥ 40 years old at pregnancy, smoking history, and steroid administration.

CONCLUSION

We investigated fracture cases occurring within 2 years of an obstetrics hospitalization. This finding may be useful in selecting preventative measures for patients at risk of fractures within 2 years after obstetric hospitalization, including PLO.

"Pregnancy and Lactation Associated Osteoporosis"

Pregnancy-associated osteoporosis (PAO) is a rare condition of skeletal fragility affecting women in pregnancy or the postpartum period. During normal pregnancy and lactation, substantial changes in calcium metabolism and skeletal physiology occur in order to meet the demands of the developing foetus. Whilst these adaptations are reversible and generally of no clinical consequence for the mother, a small number of women will develop osteoporosis and suffer fragility fractures. Vertebral fractures occur most commonly in PAO and are often multiple. Due to the rarity of PAO, systematic study to date has been limited. Aetiology is poorly understood, but traditional osteoporosis risk factors and genetic factors are likely to play a role. A small number of cases may be due to an underlying metabolic bone disorder or monogenic condition. Management of PAO is challenging, due both to a poor evidence base and the fact that spontaneous improvement in BMD is known to occur once pregnancy and lactation are complete. Bisphosphonates, denosumab and teriparatide have all been used in individual patients, but the data supporting their use are currently limited.

Unusual presentation of atraumatic insufficiency pelvic fractures unmasking pregnancy-related osteoporosis: A case report

We describe the case of a young 27-year-old Caucasian female who presented in the third trimester of her first pregnancy with sudden and severe suprapubic and left-sided hip pain without history of trauma. She was eventually diagnosed with two insufficiency fractures of the pelvis. The underlying diagnosis was pregnancy-related osteoporosis. Her baby was delivered successfully at term, with an elective caesarean section. The diagnosis was eventually made using a magnetic resonance imaging scan. Pregnancy-related osteoporosis is relatively rare, and cases of patients presenting with insufficiency fractures of this condition are rarer still. Our case raises the importance of considering this diagnosis in females in the later stages of pregnancy, with severe sudden hip or pelvis pain. The patient gave informed written consent for the publication of this case.

Pregnancy- and lactation-associated osteoporosis with vertebral fractures: a systematic review

BACKGROUND

To review, analyze and characterize the pregnancy and lactation-related osteoporosis (PLO) with vertebral fractures based on the extraction data in the previous studies.

METHODS

A comprehensive literature search of electronic databases including the PubMed, Embase and Web of Science was conducted from January 1st,1990 to December 1st, 2020. The enrolled data were pooled to analyze the baseline characteristics, clinical features, risk factors and treatment options.

RESULTS

A total of 65 articles with 338 cases were enrolled for data extraction. The enrolled cases aged from 19 to 47 years, with a mean value of 35.7 years old. The average body mass index (BMI) was 22.2 kg/m2 ranged from 16.0 to 39.0 kg/m2. Of the 173 cases, 149 cases with vertebral fractures occurred in the first pregnancy, 19 cases in the second pregnancy, four cases in the third pregnancy and one case in the fourth pregnancy. Up to 91.5% of the back pain occurred within the last 3 months of pregnancy and the first 3 months after delivery. The most involved vertebral levels were L2, L1 and T12 accounting for 32.6% of all the fractures. The average fracture numbers were 4.4 levels per patient. The lumbar Z-scores were mostly recorded with a mean value of - 3.2 ranged from - 7.8 to 0.

CONCLUSIONS

PLO with vertebral fractures is a rare clinical entity, which is more likely to occur in older and thinner pregnant women. Back pain is the clinical complaint and mostly occurs in the late pregnancy and early lactation periods. Most vertebral fractures appear in the first pregnancy but it can occur in any time of pregnancy. Thoracolumbar region is the mostly involved region. As compared with postmenopausal osteoporotic fractures, PLO usually has multiple levels fractures. Bisphosphonates are the most widely used treatment so far, however, many factors need to be taken into account to decide which drug to choose in PLO and further studies are necessary for clear recommendation in the future.

Femoral µCT Analysis, Mechanical Testing and Immunolocalization of Bone Proteins in β-Hydroxy β-Methylbutyrate (HMB) Supplemented Spiny Mouse in a Model of Pregnancy and Lactation-Associated Osteoporosis

A metabolite of leucine, ß-hydroxy-ß-methylbutyrate (HMB), used as a dietary supplement effects muscle tissue gain and bone tissue quality. Since there are no studies on the effects of HMB during pregnancy yet, the aim of the current study was to determine the effects of HMB supplementation during pregnancy on osteoporotic bone quality postpartum and post-lactation using spiny mice (Acomys cahirinus) as the animal models. The six-month-old dams were divided into four groups: pregnant and lactating controls, and pregnant and lactating HMB-treated (during the second trimester of pregnancy) females. The intensity of the immunoreaction of osteocalcin (OC), osteoprotegerin (OPG), bone morphogenetic protein 2 (BMP-2), tissue inhibitor of metalloproteinases 2 (TIMP-2), matrix metalloproteinase 8 and 13 (MMP-8 and MMP-13) and proteins involved in bone turnover, was measured in femoral trabecular and compact bone, as well as in the hyaline and epiphyseal cartilage of the femora. The analysis of the trabecular bone microarchitecture showed that the administration of HMB to pregnant females, by influencing the proteins responsible for bone cell activity and collagen remodeling, can provide protection from bone loss. Based on the results of the current study it can be assumed that HMB administration to pregnant females has a more positive impact on trabecular than compact bone.

β-Hydroxy-β-Methylbutyrate (HMB) Supplementation Prevents Bone Loss during Pregnancy-Novel Evidence from a Spiny Mouse (Acomys cahirinus) Model

The aim of this study was to determine the effects of ß-hydroxy-ß-methylbutyrate (HMB) supplementation during pregnancy on postpartum bone tissue quality by assessing changes in trabecular and compact bone as well as in hyaline and epiphyseal cartilage. The experiment was carried out on adult 6-month-old female spiny mice (Acomys cahirinus) divided into three groups: pregnant control (PregCont), pregnant HMB-treated (supplemented with 0.02 g/kg b.w of HMB during the second trimester of pregnancy, PregHMB), and non-pregnant females (NonPreg). Cross-sectional area and cortical index of the femoral mid-shaft, stiffness, and Young modulus were significantly greater in the PregHMB group. Whole-bone mineral density was similar in all groups, and HMB supplementation increased trabecular number. Growth plate cartilage was the thinnest, while the articular cartilage was the thickest in the PregHMB group. HMB supplementation increased the content of proteoglycans in the articular cartilage and the percentage of immature collagen content in metaphyseal trabeculae and compact bone. In summary, dietary HMB supplementation during the second trimester of pregnancy intensifies bone metabolic processes and prevents bone loss during pregnancy.

A case of pregnancy and lactation-associated osteoporosis and a review of the literature

INTRODUCTION

The pregnancy and lactation-associated osteoporosis (PLO) is a rare disease whose precise pathophysiological mechanisms remain mostly unknown.

CASE REPORT

We reported here a case of PLO that occurred in the early postpartum period and led to multiple compression fractures. Combination therapy with alendronate, calcium carbonate, and vitamin D was used to treat the patient and a marked but gradual increase in the density of bone mineral was observed. Moreover, no further fractures have occurred.

CONCLUSION

PLO is a very rare type of osteoporosis associated with severe chronic back pain. Increased bone resorption significantly increases the risk of bone fractures in women with PLO. Early diagnosis, stopping breastfeeding, treatment of calcium and vitamin D, bisphosphonates, or other antiosteoporosis medicine and regular follow-ups of these cases are particularly important in the prevention of fractures and to increase the quality of life of patients.

How does women's bone health recover after lactation? A systematic review and meta-analysis

This is a systematic review aiming to evaluate the recovery of bone mass after lactation-related loss. Bone loss is transitory with recovery depending on the return of menstruation and weaning, and several compensatory homeostatic mechanisms are involved to minimize any significant damage to the maternal skeleton. Lactation has been associated with significant temporary bone loss, especially during the exclusive breastfeeding period. In the bone recovery phase, there is wide methodological heterogeneity among clinical trials, including follow-up timing, methods and sites of bone measurements, and body composition changes. The purpose of this study is to perform a systematic review and meta-analysis aiming to evaluate the recovery rate of bone mass after lactation-related loss, including the PubMed, Web of Science, and Scopus databases, with no publication date restrictions. The following MeSH terms were used: "bone diseases," "bone resorption," "bone density," "osteoporosis," "calcium," "postpartum period," "weaning," "breast feeding," and "lactation." The inclusion criteria were as follows: prospective human studies in women of reproductive age and bone measurements with two assessments in the postpartum period at least: the first one within the first weeks of lactation and another one 12 months after delivery, 3 months following the return of menses or 3 months postweaning. This research was recorded on the Prospero database (CRD42018096586Bone). A total of 9455 studies were found and 32 papers met the inclusion criteria. The follow-up period ranged from one to 3.6 years postpartum. Lactation was associated with transient bone loss, with a strong tendency to recover in all the sites studied, depending on the return of menstruation and weaning. Small deficits in the microarchitecture of the peripheral skeleton may be present, especially in women with prolonged breastfeeding, but with no deficit regarding the hip geometry was found. Women with a successive gestation after prolonged lactation and women who had breastfed when adolescents had no significant bone loss. Bone loss related to lactation is transitory, and several compensatory homeostatic mechanisms are involved to minimize any significant damage to the maternal skeleton.

Women With Pregnancy and Lactation-Associated Osteoporosis (PLO) Have Low Bone Remodeling Rates at the Tissue Level

Pregnancy and lactation-associated osteoporosis (PLO) is a rare, severe, early form of osteoporosis in which young women present with fractures, usually multiple vertebral fractures, during late pregnancy or lactation. In studies of idiopathic osteoporosis (IOP) in premenopausal women, we enrolled 78 women with low-trauma fractures and 40 healthy controls, all with normal menses and no secondary cause of bone loss. In 15 of the affected women, the PLO subgroup, fractures had occurred during late pregnancy or lactation. We hypothesized that clinical, bone structural, and metabolic characteristics would differ between women with PLO and those with (non-PLO) IOP and controls. All were evaluated > 12 months postpartum, when structural and remodeling characteristics would be expected to reflect baseline premenopausal status rather than transient postpartum changes. As previously reported, affected subjects (PLO and IOP) had BMD and microarchitectural deficiencies compared to controls. Women with PLO did not differ from those with IOP in terms of age, BMI, body fat, menarcheal age, parity, or age at first pregnancy. However, women with PLO had a more severe clinical presentation than those with IOP: more fractures (5.5 ± 3.3 versus 2.6 ± 2.1; p = 0.005); more vertebral fractures (80% versus 17%; p < 0.001); and higher prevalence of multiple fractures. BMD deficits were more profound and cortical width tended to be lower in PLO. PLO subjects also had significantly lower tissue-level mineral apposition rate and bone formation rates (0.005 ± 0.005 versus 0.011 ± 0.010 mm² /mm/year; p = 0.006), as well as lower serum P1NP (33 ± 12 versus 44 ± 18 µg/L; p = 0.02) and CTX (257 ± 102 versus 355 ± 193 pg/mL; p = 0.01) than IOP. The finding that women with PLO have a low bone remodeling state assessed more than a year postpartum increases our understanding of the pathogenic mechanism of PLO. We conclude that women with PLO may have underlying osteoblast functional deficits which could affect their therapeutic response to osteoanabolic medications. © 2019 American Society for Bone and Mineral Research.

Clinical characteristics and bisphosphonates treatment of rare pregnancy- and lactation-associated osteoporosis

Pregnancy- and lactation-associated osteoporosis (PLO) is a rare disorder with poorly known etiology, pathophysiology, and therapy. We aimed to investigate the clinical characteristics of PLO and evaluate the effectiveness and safety of bisphosphonates on it. A total of 12 patients were diagnosed with PLO on the basis of medical history, bone mineral density (BMD), and/or fragility fractures during pregnancy and lactation. We investigated the clinical, biochemical, and radiological characteristics of patients. We assessed the effects of alendronate or zoledronic acid through observing the changes of bone turnover biomarkers and BMD during the treatment. Secondary osteoporosis was excluded by comprehensive differential diagnosis. The mean age of these patients was 31 ± 5 years old. All of these patients presented severe back pain. Multiple vertebral compression fractures (VCFs) were found in 10 patients, and the median (P25th, P75th) number of compressed vertebra was 3 (3, 5). Ten patients had vitamin D insufficiency or deficiency. Serum level of bone resorption marker (β-CTX with mean of 0.68 ± 0.41 ng/ml) was moderately higher than the normal range. BMD at lumbar spine, femoral neck, and total hip were low as 0.894 ± 0.153 g/cm², 0.728 ± 0.090 g/cm², and 0.728 ± 0.080 g/cm², respectively. Either alendronate or zoledronic acid could effectively relieve bone pain, reduce β-CTX level, and increase BMD. PLO is a rare type of osteoporosis, which was characterized by increased bone resorption and decreased BMD, even VCFs. Bisphosphonate therapy was well tolerated and effective in management of PLO, but needed to be further verified in randomized controlled trial.

Could use of Selective Serotonin Reuptake Inhibitors During Lactation Cause Persistent Effects on Maternal Bone?

The lactating mammary gland elegantly coordinates maternal homeostasis to provide calcium for milk. During lactation, the monoamine serotonin regulates the synthesis and release of various mammary gland-derived factors, such as parathyroid hormone-related protein (PTHrP), to stimulate bone resorption. Recent evidence suggests that bone mineral lost during prolonged lactation is not fully recovered following weaning, possibly putting women at increased risk of fracture or osteoporosis. Selective Serotonin Reuptake Inhibitor (SSRI) antidepressants have also been associated with reduced bone mineral density and increased fracture risk. Therefore, SSRI exposure while breastfeeding may exacerbate lactational bone loss, compromising long-term bone health. Through an examination of serotonin and calcium homeostasis during lactation, lactational bone turnover and post-weaning recovery of bone mineral, and the effect of peripartum depression and SSRI on the mammary gland and bone, this review will discuss the hypothesis that peripartum SSRI exposure causes persistent reductions in bone mineral density through mammary-derived PTHrP signaling with bone.

Lactation induces increases in the RANK/RANKL/OPG system in maxillary bone

The underlying causes of maxillary bone loss during lactation remain poorly understood. We evaluated the impact of lactation on physiological and mechanically-induced alveolar bone remodeling. Nulliparous non-lactating (N-LAC) and 21-day lactating (LAC) mice underwent mechanically-induced bone remodeling by orthodontic tooth movement (OTM). Micro-computed tomography (microCT) was performed in the maxilla, femur and vertebra. Tartrate-resistant-acid phosphatase (TRAP) and Masson's trichrome labelling was performed in the maxillary bone and gene expression was determined in the periodontal ligament. The effect of prolactin on osteoclast (OCL) and osteoblast (OBL) differentiation was also investigated in N-LAC and LAC mice. Lactation increased alveolar bone loss in the maxilla, femur and vertebra, while OTM was enhanced. The number of OCL and OBL was higher in the maxilla of LAC mice. OTM increased OCL in both groups; while OBL was increased only in N-LAC but not in LAC mice, in which cell numbers were already elevated. The alveolar bone loss during lactation was associated with increased expression of receptor activator of nuclear factor-KappaB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in the maxilla. OTM induced the same responses in N-LAC mice, whereas it had no further effect in LAC mice. Lactation enhanced differentiation of OCL and OBL from bone marrow cells, and prolactin recapitulated OCL differentiation in N-LAC mice. Thus, lactation increases physiological maxillary bone remodeling and OTM, and both require activation of RANK/RANKL/OPG system. These findings expand our knowledge of lactation-induced osteopenia and have possible impact on clinical practice regarding orthodontic treatments and dental implants in lactating women.

Zoledronic Acid Regulates Autophagy and Induces Apoptosis in Colon Cancer Cell Line CT26

Zoledronic acid (ZOL) is the third generation of bisphosphonates, which can inhibit many tumors growth, especially to inhibit the growth of colon cancer. However, the molecular mechanism is still very mysterious. In this study, we observed that ZOL could regulate CT26 colon cancer cells autophagy, promote CT26 cells apoptosis, and inhibit CT26 cells proliferation. Western blotting analysis showed that proapoptosis protein caspase-3 was basically unchanged, whereas the expression of the activated caspase-3 was significantly increased, after CT26 cells were treated with different doses of zoledronic acid. Western blot also showed that ZOL could significantly affect the expression of p-p53 and autophagy-related proteins beclin-1 and p62. In conclusion, the antitumor effect of ZOL on CT26 colon cancer cells in vitro is achieved by apoptosis induction and autophagy regulation, resulting in inhibition of cell proliferation.