Quantitative ultrasonometry during pregnancy and lactation: a longitudinal study

Dietary Diversity, Micronutrient Adequacy and Bone Status during Pregnancy: A Study in Urban China from 2019 to 2020

Diet quality during reproduction is crucial to maternal and infant health. However, the association between dietary diversity and bone health of pregnant women remains unclear. We aimed to evaluate the dietary quality of Chinese urban gravidas using the dietary diversity score (DDS), and to explore the relationship of the DDS with micronutrient adequacy and bone health. In this cross-sectional study, we analyzed data from 775 pregnant women aged 18 years or older in urban China. Dietary diversity was assessed using the Minimum Dietary Diversity for Women (MDD-W) indicator. A 24-h dietary recall was used to collect diet data and to calculate the MDD-W and the nutrient intake. Bone health was measured using quantitative ultrasound and assessed by the speed of sound (SOS). Pearson's correlation coefficients between the DDS and the nutrient adequacy ratio (NAR) were calculated. A multivariable linear regression model was used to estimate the effect size of the DDS on the SOS. The mean DDS was 6.61 ± 1.53 points and 91.0% of participants reported the consumption of five or more food groups. Women in the diverse diet subgroup (DDS ≥ 7 points) were more likely to consume all kinds of food except starchy staples and had higher NARs. Pearson's correlation coefficients between the DDS and the NAR ranged from 0.161 to 0.484. For participants in the second trimester, those with a diverse diet had a higher SOS. A multivariable linear regression analysis showed that the DDS was positively and significantly associated with the SOS (β = 17.18, 95% CI = 5.97-28.39, p = 0.003), but this was not the case for women in the first and third trimesters. Urban Chinese women had good dietary diversity during pregnancy. A higher dietary diversity was associated with a higher NAR. From the point of view of bone, a diverse diet was positively correlated with better bone status, suggesting the importance of improving diet diversity for pregnant women, especially from mid-pregnancy.

The influence of lactation and its duration on bone mineral density in pregnancy and postpartum: A systematic review with meta-analysis

BACKGROUND

There is a plethora of research on the association of parity and duration of lactation with bone mineral density (BMD) during and after pregnancy. However, there are no consensus conclusions on the impact of the duration of lactation on BMD.

AIMS

The aim of this study was to examine the effect of pregnancy, and the duration of lactation on BMD during pregnancy, postpartum phase and 12 months post-delivery.

METHODS

The search terms 'parity' 'lactation' 'BMD' were searched for using PubMed, CINAHL, SCOPUS and EMBASE databases in English language. Two independent reviewers assessed the quality of the included studies using Critical Appraisal Skills Program (CASP) appraisal tool and extracted data on BMD (g/cm²) in Excel. A meta-analysis was conducted with a random effect model using Cochrane Review Manager (Rev 5.4) to analyse the outcome. Heterogeneity was assessed with Chi Squared and I² test. The duration of lactation was grouped into short lactation duration (SLD), ≤4 months and longer lactation duration (LLD) > 6 months.

RESULTS

Twenty-one studies were included in this review with four studies included in the meta-analysis. BMD reduced during pregnancy and lactation. Recovery and net gains in BMD followed weaning. However, at 12 months postpartum, women in the LLD group had significant losses at the lumbar spine while those in the SLD recovered BMD. Between the SLD and LLD groups, the change in BMD was not significant 0.48 g/cm² (95% CI -0.14, 1.10, p = 0.13). BMD losses were greater in primiparous women than multiparous women.

CONCLUSION

Women who breastfed for >6 months had significantly reduced BMD. However, compared to women that breastfed for a ≤4 months there was no significant change in BMD. Further investigation is needed to clarify the association between lactation and BMD in a postpartum population in those women extending breastfeeding beyond one year.

Bone Health Assessed by Calcaneal Quantitative Ultrasound among Cohort of Pregnant Egyptian Women

Aim

The aim was to assess the risk of osteopenia and osteoporosis and to identify possible risk factors affecting bone density (BD) during pregnancy as parity, body mass index (BMI), Vitamin D, and calcium supplementation using quantitative ultrasound (QUS) of the calcaneus among first- and third-trimester pregnant women.

Methods

It is a case-control study conducted at Ain Shams Maternity Hospital, Egypt, from May 7 to December 14, 2015. One hundred and thirty-two women in the third trimester and 33 matched controls in the first trimester were screened for BD at the calcaneus by QUS. Stiffness index (SI), QUS-T, and Z scores were measured.

Results

Comparing both the groups regarding QUS-T score, Z score, and SI showed a statistically significant difference between both groups. Third-trimester participants had lower scores (-0.72 ± 1.0, -0.63 ± 0.99, and 88.53 ± 14.81, respectively) compared to their matched controls (1.05 ± 0.89, 1.16 ± 0.91, and 113.79 ± 12.49, respectively). According to QUS-T scores, 82 women (62.1%) in the third-trimester group were assessed as having normal BD, whereas 47 women (35.6%) were at risk of being osteopenic and 3 women (2.3%) were at risk of being osteoporotic. All women of the first trimester were assessed as having normal BD. Logistic regression was performed to identify possible risk factors affecting BD among third-trimester patients. BMI was the only statistically significant predictor for changes in bone health in those women (P = 0.001, odds ratio: 0.857, 95% confidence interval: 0.786-0.936).

Conclusion

With one-unit rise in BMI, a 14% reduction in risk of decreased bone health is obtained.

Parathyroid hormone in Sri Lankan pregnant women: Vitamin D and other determinants

Introduction

Determinants of parathyroid hormone level during pregnancy have been less frequently studied. We aimed to describe the serum parathyroid hormone (PTH) and its determinants in Sri Lankan pregnant women in a community setting.

Materials and methods

In this cross-sectional analysis, 390 pregnant mothers in their third trimester were enrolled from primary care centers of 15 health divisions in the Colombo District in Sri Lanka. Venous blood was analyzed for a total 25-hydroxyvitamin-D [25(OH)D], serum parathyroid hormone (PTH), serum calcium, and alkaline phosphatase. The bone quality was assessed in terms of speed of sound (SOS) using the quantitative ultrasound scan (QUS). Univariate and multivariate regression analysis was used to examine the determinants of PTH concentration in blood.

Results

Median serum 25(OH)D was 17.5ng/mL. Most (61.6%) were vitamin D deficient (<20ng/mL). Median PTH was 23.7pg/mL. Only 0.8% had hyperparathyroidism (PTH >65pg/mL). The correlation between 25(OH)D and PTH was weak but significant (r = -0.197; p<0.001). SOS Z-score was below the cut-off (≤−2) in fifty-six women (14.7%), and SOS did not relate significantly to PTH. In regression analysis, serum 25(OH)D, serum calcium, body mass index, educational level, and weeks of pregnancy were significant independent variables when adjusted. The model explained 16% of the variation in the PTH level.

Conclusions

A high prevalence of vitamin D deficiency was observed among Sri Lankan pregnant women in the present study. Serum 25(OH)D, calcium, weeks of pregnancy, and educational level were determinants of serum PTH.

Lactation alters fluid flow and solute transport in maternal skeleton: A multiscale modeling study on the effects of microstructural changes and loading frequency

The female skeleton undergoes significant material and ultrastructural changes to meet high calcium demands during reproduction and lactation. Through the peri-lacunar/canalicular remodeling (PLR), osteocytes actively resorb surrounding matrix and enlarge their lacunae and canaliculi during lactation, which are quickly reversed after weaning. How these changes alter the physicochemical environment of osteocytes, the most abundant and primary mechanosensing cells in bone, are not well understood. In this study, we developed a multiscale poroelastic modeling technique to investigate lactation-induced changes in stress, fluid pressurization, fluid flow, and solute transport across multiple length scales (whole bone, porous midshaft cortex, lacunar-canalicular pore system (LCS), and pericellular matrix (PCM) around osteocytes) in murine tibiae subjected to axial compression at 3 N peak load (~320 με) at 0.5, 2, or 4 Hz. Based on previously reported skeletal anatomical measurements from lactating and nulliparous mice, our models demonstrated that loading frequency, LCS porosity, and PCM density were major determinants of fluid and solute flows responsible for osteocyte mechanosensing, cell-cell signaling, and metabolism. When loaded at 0.5 Hz, lactation-induced LCS expansion and potential PCM reduction promoted solute transport and osteocyte mechanosensing via primary cilia, but suppressed mechanosensing via fluid shear and/or drag force on the cell membrane. Interestingly, loading at 2 or 4 Hz was found to overcome the mechanosensing deficits observed at 0.5 Hz and these counter effects became more pronounced at 4 Hz and with sparser PCM in the lactating bone. Synergistically, higher loading frequency (2, 4 Hz) and sparser PCM enhanced flow-mediated mechanosensing and diffusion/convection of nutrients and signaling molecules for osteocytes. In summary, lactation-induced structural changes alter the local environment of osteocytes in ways that favor metabolism, mechanosensing, and post-weaning recovery of maternal bone. Thus, osteocytes play a role in balancing the metabolic and mechanical functions of female skeleton during reproduction and lactation.

The influence of lactation on BMD measurements and TBS: a 12-month follow-up study

Although lactation is associated with transient bone loss and body weight changes, the unchanged TBS could highlight a limited effectiveness in detecting dynamic bone properties in the first year postpartum.

PURPOSE

To evaluate trabecular bone score (TBS) and bone mineral density (BMD) in postpartum women.

METHODS

This was a 12-month prospective cohort study with 40 lactating postpartum women and 44 non-pregnant women. The inclusion criteria were as follows: aged between 18 and 35 years old, an uncomplicated term (≥37 weeks) pregnancy with a single fetus, and no intention of becoming pregnant within 12 months. BMD measurements, including spine, hip, forearm and whole body, were performed by DXA at four different time points after delivery: (1) 1st month, (2) 3rd-4th month, (3) 6th-9th month, and (4) ≥ 12th month postpartum.

RESULTS

BMD measurements showed a statistically significant decrease at spine (1.134 vs. 1.088 g/cm², p < 0.01), femoral neck (0.988 vs. 0.946 g/cm², p < 0.01), total femur (0.971 vs. 0.933 g/cm², p < 0.01), and whole body (1.132 vs. 1.119 g/cm², p = 0.03) at the 2nd assessment (peak of lactation). There was early spinal recovery after the 3rd assessment with complete recovery in all skeletal sites. Although it has had significant weight loss (67.3 vs. 63.2 kg, p < 0.01) and body mass index reduction (25.2 vs. 23.4, p < 0.01), there was significant increment of spine BMD (1.134 vs. 1.165 g/cm², p < 0.01) after 12-month follow-up. The TBS did not change over time.

CONCLUSIONS

Although lactation is associated with transient bone loss and body weight changes, the unchanged TBS could highlight a limited effectiveness in detecting dynamic bone properties in the first year postpartum.

Osteoporosis in Premenopausal Women: A Clinical Narrative Review by the ECTS and the IOF

CONTEXT

Consensus regarding diagnosis and management of osteoporosis in premenopausal women (PW) is still lacking due to few studies carried out in this population.

DESIGN

The European Calcified Tissue Society and the International Osteoporosis Foundation convened a working group to produce an updated review of literature published after 2017 on this topic.

RESULTS

Fragility fractures in PW are rare and mostly due to secondary osteoporosis (ie, in presence of an underlying disease such as hormonal, inflammatory, or digestive disorders). In absence of another disorder, low bone mineral density (BMD) together with fragility fractures qualifies as idiopathic osteoporosis. In contrast, low BMD alone does not necessarily represent osteoporosis in absence of bone microarchitectural abnormalities. BMD increases in PW with osteoporosis when the underlying disease is treated. For example, in celiac disease, an increase of 9% in radius trabecular volumetric density was achieved after 1 year of gluten-free diet, while anti-tumor necrosis factor alpha improved BMD in PW with inflammatory bowel diseases. In amenorrhea, including anorexia nervosa, appropriately delivered estrogen replacement therapy can also improve BMD. Alternatively, antiresorptive or anabolic therapy has been shown to improve BMD in a variety of conditions, the range of improvement (3%-16%) depending on skeletal site and the nature of the secondary cause. No studies were powered to demonstrate fracture reduction. The effects of bisphosphonates in childbearing women have been scantly studied and caution is needed.

CONCLUSION

The majority of PW with osteoporosis have an underlying disease. Specific therapy of these diseases, as well as antiresorptive and anabolic drugs, improve BMD, but without evidence of fracture reduction.

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.

25-Hydroxyvitamin D profiles and maternal bone mass during pregnancy and lactation in Japanese women

Vitamin D deficiency is observed worldwide and represents a health hazard for mothers, infants and elderly persons. We know that many young Japanese women experience vitamin D insufficiency; however, there is a lack of knowledge regarding the serum 25-hydroxyvitamin D [25(OH)D] profile of pregnant Japanese women and of the association between maternal 25(OH)D level and maternal bone mass during pregnancy and lactation. In this longitudinal study, 160 pregnant Japanese women were enrolled; of them, 68 have been followed-up from the first trimester through at least 1 year of breast-feeding. We estimated serum 25(OH)D levels, intact PTH levels, calcaneus quantitative ultrasound (QUS: T score) scores, bone mineral density at the distal one-third of the radius, dietary intakes according to the Food Frequency Questionnaire, and sunlight exposure times. We found that Vitamin D deficiency is prevalent in Japanese women, irrespective of pregnancy or lactation, and our analysis suggested that 25(OH)D levels and BMI in the first trimester were related to the lactating women's bone mass from after delivery to 1 year after delivery.

Mechanical Regulation of the Maternal Skeleton during Reproduction and Lactation

PURPOSE OF REVIEW

This review summarizes recently published data on the effects of pregnancy and lactation on bone structure, mechanical properties, and mechano-responsiveness in an effort to elucidate how the balance between the structural and metabolic functions of the skeleton is achieved during these physiological processes.

RECENT FINDINGS

While pregnancy and lactation induce significant changes in bone density and structure to provide calcium for fetal/infant growth, the maternal physiology also comprises several innate compensatory mechanisms that allow for the maintenance of skeletal mechanical integrity. Both clinical and animal studies suggest that pregnancy and lactation lead to adaptations in cortical bone structure to allow for rapid calcium release from the trabecular compartment while maintaining whole bone stiffness and strength. Moreover, extents of lactation-induced bone loss and weaning-induced recovery are highly dependent on a given bone's load-bearing function, resulting in better protection of the mechanical integrity at critical load-bearing sites. The recent discovery of lactation-induced osteocytic perilacunar/canalicular remodeling (PLR) indicates a new means for osteocytes to modulate mineral homeostasis and tissue-level mechanical properties of the maternal skeleton. Furthermore, lactation-induced PLR may also play an important role in maintaining the maternal skeleton's load-bearing capacity by altering osteocyte's microenvironment and modulating the transmission of anabolic mechanical signals to osteocytes. Both clinical and animal studies show that parity and lactation have no adverse, or a positive effect on bone strength later in life. The skeletal effects during pregnancy and lactation reflect an optimized balance between the mechanical and metabolic functions of the skeleton.

Association between dietary inflammatory index and bone density in lactating women at 6 months postpartum: a longitudinal study

Background

Chronic inflammation contributes to the risk of osteoporosis and fracture. Dietary Inflammatory Index (DII), a novel method appraising the inflammatory potential of diet, has been utilized to examine the association between diet and bone health among postmenopausal women or the elderly. However, its relationship with bone density (BD) in lactating women has not been studied.

Methods

The prospective study was conducted to assess the possible association between DII and maternal BD during lactation. We enrolled 150 lactating women in the cohort. Participants were measured ultrasonic BD as baseline values at 1 month postpartum. After five-month follow up, the participants’ BD were measured again. DII scores were calculated from semi-quantitative food frequency questionnaires (FFQ) and divided into tertiles. We compared the differences in the changes of BD at 6 months postpartum without or with adjustment for potential covariates across the tertiles.

Results

The women in Q1 of DII scores had less bone mass loss than those in Q2 and Q3 without adjustment for any covariates (p < 0.01); after adjusting demographic characteristics such as BMI (kg/m²) at 6 months postpartum, educational level, metabolic equivalent (MET), daily energy intake (kcal/d), we found that participants in the highest tertile of DII scores had much more bone loss than those in the lowest tertile (p = 0.038). However, in the test for trend, no significant association between DII and the changes of maternal BD at 6 months postpartum was observed.

Conclusions

Chinese lactating women with higher DII scores have more bone mass loss; however significant differences and trends are attenuated and/or disappear depending on covariates and confounders that are taken into account in statistical analysis. The further study should be conducted in larger population to explore whether the significant association between DII and BD exists in Chinese lactating women.

Mutational analysis uncovers monogenic bone disorders in women with pregnancy-associated osteoporosis: three novel mutations in LRP5, COL1A1, and COL1A2

Pregnancy was found to be a skeletal risk factor promoting the initial onset of previously unrecognized monogenic bone disorders, thus explaining a proportion of cases with pregnancy-associated osteoporosis. Therapeutic measures should focus in particular on the normalization of the disturbed calcium homeostasis in order to enable the partial skeletal recovery.

INTRODUCTION

Pregnancy-associated osteoporosis (PAO) is a rare skeletal condition, which is characterized by a reduction in bone mineral density (BMD) in the course of pregnancy and lactation. Typical symptoms include vertebral compression fractures and transient osteoporosis of the hip. Since the etiology is not well understood, this prospective study was conducted in order to elucidate the relevance of pathogenic gene variants for the development of PAO.

METHODS

Seven consecutive cases with the diagnosis of PAO underwent a skeletal assessment (blood tests, DXA, HR-pQCT) and a comprehensive genetic analysis using a custom-designed gene panel.

RESULTS

All cases showed a reduced BMD (DXA T-score, lumbar spine - 3.2 ± 1.0; left femur - 2.2 ± 0.5; right femur - 1.9 ± 0.5), while the spine was affected more severely (p < 0.05). The trabecular and cortical thickness was overall reduced in HR-pQCT, while the trabecular number showed no alterations in most cases. The genetic analysis revealed three novel mutations in LRP5, COL1A1, and COL1A2.

CONCLUSION

Our data show that previously unrecognized monogenic bone disorders play an important role in PAO. Pregnancy should be considered a skeletal risk factor, which can promote the initial clinical onset of such skeletal disorders. The underlying increased calcium demand is essential in terms of prophylactic and therapeutic measures, which are especially required in individuals with a genetically determined low bone mass. The implementation of this knowledge in clinical practice can enable the partial recovery of the skeleton. Consistent genetic studies are needed to analyze the frequency of pathogenic variants in women with PAO.

Subsequent fracture risk of women with pregnancy and lactation-associated osteoporosis after a median of 6 years of follow-up

Almost a quarter of patients with PAO will sustain a subsequent fracture; patients need to be informed about potential risks before deciding for further pregnancies.

INTRODUCTION

Pregnancy and lactation-associated osteoporosis (PAO) is a severe type of premenopausal osteoporosis which predominantly occurs in the last trimester of pregnancy or immediately postpartum. Long-term follow-up data including subsequent fracture risk have yet to be reported.

METHODS

This single-center prospective cohort study investigated the subsequent fracture risk of all 107 patients with PAO who were referred to our institution.

RESULTS

Overall, 107 presented with at least one fracture. Each patient sustained on average four fractures most commonly at the thoracolumbar spine. During a median of 6 years of follow-up, 26 (24.3%) of patients who had a fracture at baseline reported a subsequent fracture. Overall, 30 PAO patients (28%) reported a further pregnancy. In subsequent pregnancies, 6 (20%) of patients reported a subsequent fracture. Patients with up to 1 vs. > 1 fracture at time of diagnosis showed a 3 (10%) and 25 (27%) subsequent fracture rate, respectively (p = 0.047). There was a significant correlation between the number of fractures at time of diagnosis and subsequent fracture risk (N = 26,p= 0.56, p = 0.003).

CONCLUSIONS

Almost a quarter of patients with PAO will sustain a subsequent fracture, and this fracture risk correlates with the number of fractures at time of diagnosis. Patients with PAO need to be informed about their potential subsequent fracture risk before deciding for further pregnancies.

Pregnancy-associated osteoporosis: a case-control study

The etiology and underlying mechanisms of pregnancy-associated osteoporosis (PAO) are still unknown, since no systematic analyses exist. Our results indicate that PAO is a heterogeneous, rare but severe disease including a substantial number of fractures with a significant delay from first symptom to diagnose.

INTRODUCTION

Pregnancy-associated osteoporosis (PAO) is a rare but severe type of premenopausal osteoporosis. Most common symptom includes acute lower back pain due to vertebral fracture predominantly occurring in the last trimester of pregnancy or immediately postpartum. The exact underlining mechanisms and risk factors of PAO are still unknown, and up to date, there are no published systematic analyses.

METHODS

We identified 102 PAO patients and matched them with 102 healthy controls according to age, region, and gravidity to evaluate risk factors in a large and homogenous population of women.

RESULTS

The baseline characteristics and anthropometric data of the two study groups were similar. Eighty-eight percent of the patients with PAO suffered from one or more fractures with a mean of 3.3 fractures per patient. The most common fracture site was the thoracolumbar spine, whereas 29, 37, 48, and 35% of the patients reported fractures at TH11, TH12, L1, and L2, respectively. PAO patients suffered more frequently from excessive dental problems in childhood (p < 0.001). The control group performed significantly more frequently sports both before (p < 0.002) and after puberty (p < 0.01). Compared to the controls, the patients with PAO reported twice as often severe diseases during pregnancy (p < 0.029). Hereby, the frequency of immobilization was twice as often in the PAO group compared to that in the control group (p < 0.005).

CONCLUSIONS

Our results indicate that PAO is a heterogeneous, rare but severe disease including a substantial number of fractures with a significant delay from first symptom to diagnose. Increased awareness is warranted to immediately start effective treatment.

Prevalence of Low Bone Mineral Density and Associated Risk Factors in Korean Puerperal Women

Although pregnancy is a medical condition that contributes to bone loss, little information is available regarding bone mineral density (BMD) in puerperal women. This cross sectional study aimed to evaluate the prevalence of low BMD in puerperal women and to identify associated risk factors. We surveyed all puerperal women who had BMD measurements taken 4-6 weeks after delivery in a tertiary university hospital, and did not have any bone loss-related comorbidities. Among the 1,561 Korean puerperal women, 566 (36.3%) had low BMD at the lumbar spine, total hip, femoral neck, and/or trochanter. Multivariate analysis revealed that underweight women had a significantly higher risk of low BMD compared with obese women at pre-pregnancy (adjusted odds ratio [aOR], 3.21; 95% confidence interval [CI], 1.83-5.63). Also, women with inadequate gestational weight gain (GWG) were 1.4 times more likely to have low BMD than women with excessive GWG (aOR, 1.42; 95% CI, 1.04-1.94). One-way ANOVA showed that BMDs at the lumbar spine and total hip were significantly different between the 4 BMI groups (both P < 0.001) and also between the 3 GWG groups (both P < 0.001). In conclusion, this study identifies a high prevalence of low BMD in puerperal women and thus suggests the need for further evaluation about the change of BMD in pregnancy and postpartum period.