Associations between maternal anthropometric characteristics and infant birth weight in Iranian population

Investigation of maternal polymorphisms in genes related to glucose homeostasis and the influence on birth weight: a cohort study

OBJECTIVES

To contribute to a better understanding of the maternal genetic mechanisms that influence obstetric outcomes and that are involved in maternal and child health, this study aimed to evaluate the association between maternal genetic variants and the offspring birth weight by analyzing single-nucleotide polymorphisms (SNPs) in genes related to glucose homeostasis.

METHODS

Three polymorphisms were analyzed (GCK rs1799884, TCF7L2 rs7903146 and LEPR rs1137101) in 250 pregnant women who participated in a Brazilian prospective cohort study. Genotyping was performed by Real-Time Polymerase Chain Reaction (qPCR) using pre-designed TaqMan® SNP genotyping assays. Vitamin D dosage was performed by chemiluminescence. Variance, Pearson's chi-square test and multiple linear regression were used for the statistical analysis.

RESULTS

It was possible to verify a significant association between birth weight and maternal GCK rs1799884 when obstetric outcomes, clinical and anthropometric characteristics were taken into consideration. The children of homozygous women for the minor allele GCK rs1799884 presented lower birth weight (β = -335.25, 95% CI = -669.39; -1.17, p = 0.04). Furthermore, a direct link between a leptin receptor variant and gestational duration was found (p = 0.037).

CONCLUSION

The variant GCK rs1799884 (mm) was associated with a reduction in newborn weight in the miscegenated Brazilian population.

Effect of maternal age, height, BMI and ethnicity on birth weight: an Italian multicenter study

AIM

To assess the effect of maternal age, height, early pregnancy body mass index (BMI) and ethnicity on birth weight.

SUBJECTS AND METHODS

A cross-sectional study was conducted on more than 42,000 newborns. Ethnicity was defined by maternal country of birth or, when missing (<0.6% of records), by citizenship. The effect of maternal characteristics on birth weight was evaluated with general linear models.

RESULTS

Maternal height and BMI, although not age, significantly affected birth weight. Among Italian babies, 4.7% of newborns were classified as appropriate-for-gestational age (AGA) (birth weight between the 10th and the 90th centile) according to the country-specific Italian Neonatal Study (INeS) charts and were re-classified as either large-(LGA) (birth weight >90th centile) or small-(SGA) (birth weight <10th centile) for gestational age (GA) after adjustment for maternal characteristics. On the contrary, 1.6% of Italian newborns were classified as SGA or LGA according to the INeS charts and re-classified as AGA after adjustment. Maternal ethnicity had a significant impact on birth weight. Specifically, babies born to Senegalese mothers were the lightest, whilst babies born to Chinese mothers were the heaviest.

CONCLUSIONS

Maternal height and early pregnancy BMI, should be considered in the evaluation of birth weight. The effect of ethnicity suggests the appropriateness of ethnic-specific charts. Further studies are necessary to determine if changes in birth weight classification, may translate into improved detection of subjects at risk of adverse outcomes.