The reproducibility of ultrasound bone measures in a triethnic population of pregnant adolescents and adult women

Reductions in heel bone quality across gestation are attenuated in pregnant adolescents with higher prepregnancy weight and greater increases in PTH across gestation

Few studies have examined the effect of maternal calcium intake and vitamin D status on bone health across gestation in pregnant adolescents. This study aimed to characterize maternal bone quality and determinants of bone-quality change across gestation in pregnant adolescents. Healthy pregnant adolescents (n = 156; aged 13 to 18 years) with singleton pregnancies and at 12 to 30 weeks gestation at enrollment were recruited from two urban maternity clinics in Baltimore, MD, and Rochester, NY, for this prospective longitudinal study. Maternal serum was collected at midgestation and at delivery for assessment of bone biomarkers and calcitropic hormones. Maternal bone quality (assessed by heel ultrasound) and sonographic fetal biometry were measured up to three times across pregnancy. Racially diverse teens (64.7% African American, 35.3% white) were followed from 21.0 (interquartile range [IQR] 17.3, 27.0) weeks of gestation until delivery at 40.0 (IQR 39.0, 40.7) weeks. Significant decreases in calcaneal speed of sound (SOS), broadband ultrasound attenuation (BUA), and quantitative ultrasound index (QUI) (-9.2 ± 16.1 m/s, -3.2 (-8.0, 2.1) dB/MHz and -5.3 ± 8.8, respectively) were evident across pregnancy. Multivariate analysis controlling for baseline measures and measurement intervals was used to identify independent predictors of normalized (per week) calcaneal bone loss. Weekly decreases in bone quality were not significantly associated with maternal calcium intake or 25(OH)D concentration. Greater weekly reductions in calcaneal bone quality were evident in teens with lower prepregnancy weight (BUA, p = 0.006 and QUI, p = 0.012) and among those with lower weekly increase in PTH (SOS, p = 0.046). Overall, significant decreases in calcaneal bone quality occurred across pregnancy in adolescents, but the magnitude of this loss was attenuated in those with greater prepregnancy weight and weekly increases in PTH. Further studies are needed to understand the role of elevated PTH and greater prepregnancy weight in preserving adolescent bone during pregnancy.

Quantitative bone US measurements in neonates and their mothers

BACKGROUND

Factors that affect quantitative ultrasound (QUS) bone measurements have not been clearly defined for all clinical populations.

OBJECTIVE

To determine some technical and clinical aspects that may affect QUS bone measurement in the neonate-maternal dyad.

MATERIALS AND METHODS

Speed of sound (SOS) was measured at the radius and tibia using a commercial multisite axial transmission QUS instrument and three manufacturer-provided probes (CS, CR and CM).

RESULTS

The study included 183 singleton neonates and 159 mothers. The type of probe, weight and edema significantly affected SOS measurements. In infants, the CS and CR probes measured SOS consistently at the tibia but not the radius. Gestational age was predictive of SOS from the CS probe and remained significant when race, gender, and birth weight were included. None of these parameters predicted SOS when using the CR probe. Maternal SOS at the radius and tibia was correlated with the CM probe. Maternal SOS was predicted by age but not by gravid status, number of living children, or race. There was no consistent correlation between maternal-infant dyad SOS measurements.

CONCLUSIONS

Axial transmission SOS of bone varies with probe and site and is affected by technical and clinical factors. Valid data depend on documentation of the probes used and the clinical population studied.

Bone status after cessation of use of injectable progestin contraceptives

BACKGROUND

Women using injectable progestin contraceptives (IPCs) have lower bone mineral density than nonusers. We assessed whether bone loss is completely reversible after cessation of IPC use, whether different IPCs have different effects and whether effects vary by age at first use.

STUDY DESIGN

In a cross-sectional study in Cape Town, South Africa, 3487 premenopausal black and mixed race women aged 18-44 years were interviewed for information on contraceptive history and risk factors for decreased bone mineral density, and ultrasound measurements of the left calcaneus were taken. Adjusted means of the ultrasound measures for categories of IPC use were obtained using multivariable linear regression.

RESULTS

Current users of IPCs had the lowest ultrasound measures, while the measures of women who had ceased IPC use at least 2-3 years previously were similar to or greater than those of never users of IPCs. The effects of depot medroxyprogesterone acetate and norethisterone enanthate were similar. The calcaneus measures were unrelated to age at which use began after control for confounding factors.

CONCLUSION

The data suggest that bone loss during IPC use is reversible and that this loss of bone is completely recovered several years after cessation of use.

Quantitative ultrasound at the hand phalanges in pregnancy: a longitudinal study

In the prospective study, 48 females in normal pregnancy were evaluated to determine if the presence of disturbances of maternal bone and mineral status is related to fetal and newborn growth. The aim of the study was to estimate mean and individual changes in maternal skeletal and laboratory variables during pregnancy and their correlations with fetal and newborn sizes. Maternal bone and mineral status was assessed in first, second and third trimester by quantitative ultrasound (US), or QUS, at the hand phalanges (Ad-SoS [m/s]) performed by DBM Sonic 1200 (IGEA, Carpi, Italy) and laboratory investigations were collected (serum total calcium, total alkaline phosphatase and phosphate). The hypothesis that fetus growth and sizes of the newborn may have an influence on bone and mineral status in pregnancy was tested by the correlation of ultrasonographic fetal measurements and newborn sizes with changes in maternal QUS and biochemical data. Ad-SoS decreased significantly (p < 0.00001) and alkaline phosphatase increased significantly in second and third trimester of pregnancy (p < 0.01). A decrease in Ad-SoS greater than least significant change (LSC) was observed in 22 females (46%) during pregnancy. Changes in alkaline phosphatase correlated significantly with changes in Ad-SoS (r = -0.31, p < 0.05). Fetal ultrasonographic measurements (femur length and biparietal diameter) correlated significantly with changes in alkaline phosphatase (r ranged 0.31 to 0.56, p < 0.05). No significant correlations were observed between fetal ultrasonographic measurements (femur length and biparietal diameter) and newborn size with changes in Ad-SoS. In conclusion, the study revealed considerable changes in maternal bone and mineral status in normal pregnancy.

Relationship between bone mineral density changes in pregnancy and maternal and pregnancy characteristics: a longitudinal study

OBJECTIVE

The study aims to verify whether a progressive fall in bone mineral density (BMD) values can be demonstrated using quantitative ultrasound measurements of the os calcis. The BMD change during the pregnancy was then correlated with other maternal and pregnancy characteristics to identify any high-risk factors for bone loss in pregnancy.

METHODS

Consecutive patients were recruited from a low-risk obstetric clinic over a period of 9 months. BMD measurements were performed at the os calcis before 18 weeks, between 28 and 32 weeks, and at 36-38 weeks using a Hologic Sahara Clinical Bone Sonometer system. A computer-derived BMD value was obtained with each measurement. Body fat composition was also measured using a Tanita 501 bioimpedance assay system.

RESULTS

In a cohort of 780 patients, a mean fall in BMD of 0.040 g/cm2 was demonstrable across the trimesters. The difference in BMD across the three serial measurements was highly significant (p < 0.001). Univariate analysis showed that those with a low initial BMD, glucose intolerance and high body fat accumulation weight gain during the pregnancy had lower BMD loss, while gestational hypertension and obesity had no impact on the degree of BMD loss. Entering these parameters in a logistic regression analysis showed that the impact of glucose intolerance was lost, but that the other factors remained significant. A linear regression model of quantitative variables showed that only fat accumulation (p = 0.03) and early pregnancy BMD values (p < 0.001) remained significant factors associated with BMD loss.

CONCLUSION

A gradual fall in BMD was demonstrable using ultrasound measurement of the os calcis from early to late pregnancy. Of the various parameters identified as significant factors affecting BMD loss in pregnancy, a low initial BMD in early pregnancy and high body fat accumulation during pregnancy appeared to be related to lower BMD loss.

Ethnic differences in bone mass of young women vary with method of assessment

To examine ethnic differences in bone mass measured by calcaneus ultrasound (CUS) and dual energy X-ray absorptiometry (DXA), and to compare the two methodologies, CUS was performed in 904 healthy Asian, African American, Latina, and Caucasian women 20-26 yr old using the Lunar Achilles Plus ultrasonometer. CUS measurements (broadband ultrasound attenuation [BUA] and speed of sound [SOS]) were made following standard methodology (standard CUS) and repeated adjusting for foot size using shims (with-shim CUS). Areal bone mineral density (BMD) and estimated volumetric bone density (BMAD) at the spine, femoral neck, and whole body were determined using the Lunar DPX-IQ. African Americans had greater height- and weight-adjusted BUA than Caucasians, while Asians and African Americans had greater SOS than Caucasians and Latinas. Additionally, African Americans had greater height- and weight-adjusted BMD and BMAD than all other groups. CUS and DXA measurements correlated moderately (r = 0.2-0.5). With-shim CUS values were 0.9-7.8% lower than standard CUS values. In conclusion, African American women had greater DXA measurements than all others and greater CUS measurements than Caucasians. In contrast to DXA, CUS measurements in Asians and Latinas were not significantly lower than those in African Americans. Most notably, Asians had greater values for SOS than Caucasians and Latinas. Discrepancies in ethnic comparisons and modest correlations suggest that CUS and DXA methods may capture different bone qualities.

IGF-I, osteocalcin, and bone change in pregnant normotensive and pre-eclamptic women

Pre-eclampsia is a pregnancy disorder of uncertain etiology that affects 5-10% of all pregnancies, with symptoms typically presenting around or after 20 wk gestation. We hypothesized that IGF-I, osteocalcin, and bone loss would be different among women with pre-eclampsia compared with normotensive pregnant women. There were 962 pregnant healthy women, aged 12-35, who were assessed at entry to care, at 28 wk, and at delivery for osteocalcin and IGF-I concentrations. Bone ultrasound was measured at entry to care and at 6 wk postpartum, whereas bone mineral density was measured by dual x-ray densitometry at delivery. There were 64 women (6.7%) among the women being followed who developed pre-eclampsia. In women with pre-eclampsia, IGF-I concentrations were 74% greater in the third trimester compared with the first trimester, whereas there was little change in osteocalcin concentrations. In contrast, normotensive women had an average increase of 43% in IGF-I concentrations accompanied by a 63% decline in osteocalcin concentrations. In women with pre-eclampsia, IGF-I and osteocalcin concentrations were significantly correlated (r = 0.48 and 0.43) at both the first and third trimester time points, but only in the third trimester among normotensive women (r = 0.27). The bone change difference between the two groups was not statistically significant. Women with pre-eclampsia appear to have an exaggerated IGF-I responsiveness compared with women who are normotensive; however, the strong correlation between IGF-I and osteocalcin in women with pre-eclampsia suggests that the IGF-I is able to retain its role as a local regulator of bone remodeling, as indicated by the osteocalcin concentrations.