Profiles of gene expression in maternal blood predict offspring birth weight in normal pregnancy

Associations of maternal stress, gene expression, and newborn birthweight in the Democratic Republic of Congo

Objectives

Maternal stress has long been associated with lower birthweight, which is associated with adverse health outcomes including many adult diseases. The underlying mechanisms remain elusive although changes in gene expression may play a role. Studies are only beginning to test how maternal stress impacts gene expression as reflected in the transcriptome.

Materials and Methods

In a cohort of mothers and newborns in the eastern Democratic Republic of Congo (n=93), we studied the effects of four maternal stress measures (chronic stress, war trauma, sexual trauma, and general trauma) on the transcriptomes of maternal venous blood, newborn venous blood, and placental tissues, and on newborn birthweight. Maternal stress was investigated as independent measures, principal components, and clusters identified through machine learning. The transcriptome was assayed using the ClariomD chip. Multiple regression models were used to test for associations between maternal stress measures, the transcriptome, and newborn birthweight.

Results

None of the maternal stress measures showed an association with expression of individual genes. In contrast, when testing global gene expression, war trauma was significantly associated with the placental transcriptome. War trauma was also significantly associated with birthweight in multiple models. Mediation analysis indicated that ~14% of the effect of war trauma on birthweight was mediated by a placental gene expression component.

Discussion

Our results suggest that gene expression in the placenta, which represents the interface between mother and developing fetus, may partially mediate the negative impact of maternal stress on newborn birthweight.

The effect of consuming milk and related products during human pregnancy over birth weight and perinatal outcomes: A systematic review and meta-analysis

OBJECTIVE

Data addressing the effect of milk and related products (M&RPs) on fetal growth are contradictory. The aim was to meta-analyze the effect of consuming M&RPs during human pregnancy over perinatal outcomes.

METHOD

A systematic literature search was performed in PubMed, EMBASE, Scopus, Web of Science, and Cochrane Library. Eligibility criteria for selection were: studies evaluating the effect of consuming M&RPs during pregnancy over birth weight and different perinatal outcomes. Random effect models were used for meta-analyses, and effects are reported as mean differences (MD) or odds ratio (OR) and their 95 % confidence intervals (CIs).

RESULTS

Fourteen studies (111,184 pregnant women) reported on the targeted perinatal outcomes. The meta-analysis of ten studies revealed a positive association between consuming a higher amount of M&RPs and birth weight (MD =51.0 g, 95 % CI 24.7-77.3), whereas in five studies a positive effect was observed on infant length (MD =0.33 cm, 95 % CI: 0.03-0.64). The higher birth weight was detected both in Western world gravids, consuming standard/conventional diets, as well as in vegetarian women from India. There were no significant differences in ultrasound measured fetal head circumference, biparietal diameter, abdominal circumference and femur length. The consumption of a higher amount of M&RPs was associated with a reduced risk of small-for-gestational age (SGA) (OR = 0.69, 95 % CI: 0.56-0.84) and low birth weight infants (OR = 0.63, 95 % CI: 0.48-0.84); in addition to a higher risk of large-for-gestational age (LGA) infants (OR = 1.11, 95 % CI: 1.02-1.21).

CONCLUSION

The consumption of a higher amount of M&RPs during pregnancy was associated with greater infant birth weight and length; in addition to a lower risk of having SGA and low birth weight infants, and a higher risk of LGA infants.