Gestational Weight Gain and Offspring Bone Mass: Different Associations in Healthy Weight Versus Overweight Women

Abstract

Weight management strategies during pregnancy reduce child cardiometabolic risk. However, since maternal weight has an overall positive correlation with offspring bone mass, pregnancy weight management could adversely affect child bone health. We aimed to estimate associations between gestational weight gain (GWG) and bone mineralization in the offspring at 7 years of age, and test early pregnancy body mass index (BMI) as an effect modifier. We analyzed prospective data from 2,167 mother-child pairs from the Generation XXI birth cohort who underwent whole-body dual-energy X-ray absorptiometry at 7 years of age. GWG was analyzed as a continuous measure and using the Institute of Medicine categories. In the whole sample and for each early pregnancy BMI category (under/normal weight and overweight/obese), relationships between GWG and offspring bone measures (bone mineral content, BMC, bone areal density, aBMD, size-corrected BMC, scBMC, and height) at 7 years were fitted thought local polynomial regression and smoothing splines. The magnitude of associations was estimated through linear regression coefficients (95% CIs), crude and adjusted for maternal age, height, educational level, and child gestational age. In under/normal weight mothers, GWG was associated with slightly increased bone measures at 7 years [per 5 kg of GWG, BMC: 0.07SD (95% CI: 0.01, 0.12); aBMD: 0.10SD (0.05, 0.15), scBMC: 0.11SD (0.06, 0.16), height: 0.05 SD (0.00, 0.10)], while in overweight/obese mothers no effect of GWG on bone was observed [BMC: 0.02SD (-0.04, 0.09); aBMD: 0.02SD (-0.04, 0.08), scBMC: 0.01SD (-0.06, 0.08), height: 0.02SD (-0.04; 0.08)]]. Also, no advantageous effect of gaining weight above the Institute of Medicine recommendations was observed in either early pregnancy BMI group. Our results suggest that adherence to Institute of Medicine recommendations for pregnancy weight gain is unlikely to have a negative repercussion on offspring bone health, particularly in women with excess weight in early pregnancy.

Maternal Vitamin D Status and Gestational Weight Gain as Correlates of Neonatal Bone Mass in Healthy Term Breastfed Young Infants from Montreal, Canada

“…The differences between maternal 25(OH)D categories and GWG categories in whole-body BMC (g) and BMC per body weight (BMC/kg; g/kg), lumbar spine BMC (g), and BMD (g/cm 2 ) were tested using a mixed linear model. The variables tested as fixed effects were considered based on previous research, including infant sex [40,41], age [42], and length-for-age z-scores (LAZ) [43]; maternal characteristics: 25(OH)D categories [11,24], pre-pregnancy BMI categories [14], GWG categories [38], gravida [44], and age [45]; and sociodemographic characteristics [46][47][48]: maternal education and self-reported population group, and annual family income. Given that GWG may be an effect modifier of the maternal vitamin D status-infant bone outcomes association [19], both factors were tested in the same model.…”

“…This is exemplified in the Avon Longitudinal Study of Parents and Children in which maternal exposure to ultraviolet B (UVB) radiation and folate intake during pregnancy were both positively related to childhood (9 years of age) bone mineral content (BMC) and bone mineral density (BMD) [4]. Other maternal factors related to an offspring's bone outcomes include maternal smoking [5] and alcohol consumption [6] that are negatively related to bone outcomes, whereas the relation of maternal vitamin D supplementation [7][8][9], vitamin D status [10][11][12][13], pre-pregnancy body mass index (BMI), and gestational weight gain (GWG) [14] to infant bone outcomes is equivocal.…”

“…One study from the UK suggests that the positive associations between pre-gravid BMI and child BMC and BMD at 9 years of age are possibly due to genetic and environmental influences throughout childhood rather than intrauterine exposures [16]. Another study found that GWG positively associates with BMC of the offspring at 7 years of age in mothers with a pre-gravid BMI < 25 kg/m 2 , but not in mothers with pre-gravid BMI ≥ 25 kg/m 2 [14]. As such, the relation of pre-gravid BMI and excessive GWG to offspring bone outcomes is unclear.…”

Maternal Diet, Nutritional Status, and Birth-Related Factors Influencing Offspring’s Bone Mineral Density: A Narrative Review of Observational, Cohort, and Randomized Controlled Trials

“…In one study, no association was found [ 31 ], whereas in another study a positive association was noticed but only in relation to one of the measured sites (LS BMD) [ 53 ]. The influence of pregnancy weight gain, which was investigated in three studies [ 53 , 55 , 56 ], was also ambiguous. In a study by Xu et al [ 56 ], pregnancy weight gain was positively related to offspring BMD.…”

“…In another study, a positive influence was observed only in relation to one measured site (TB BMD) [ 53 ]. Monjardino et al [ 55 ] found that maternal gestational weight gain (GWG) was associated with higher aBMD in children, but only if the mothers were under/normal weight at the beginning of pregnancy.…”