Predictors of gestational age at birth and its association with postnatal growth outcomes in preschool-age children

Background

Although the length of gestation has been shown to have an effect on pregnancy outcomes including birth weight, information regarding its effect on postnatal growth of children is scanty. The aim of this study was to assess the potential factors affecting duration of gestation, and how it associates with postnatal growth outcomes of children under two years.

Methods

This was an analytical health facility-based, cross-sectional study. A systematic random sampling technique was used, to select mother–child pairs who sought services from child welfare clinic (CWC) in the Tamale Teaching Hospital. The predictors of gestational age were identified using multivariable linear regression and hierarchical multivariable linear regression analysis was used to test the independent contribution of gestational age to length-for-age z-score (LAZ).

Results

The prevalence of late term/post-term delivery was 75 (23.5%). Older women were positively associated with longer gestational age as a unit increase in age of the mother increased gestational age by 0.28 standard units, β = 0.28, (95% CI: 0.07 to 0.20). Malarial infection during pregnancy reduced duration of gestation by 0.11 standard units, β = -0.11, (95% CI: -0.79 to -0.02). Greater weekly gestational rate of weight gain reduced gestational age by 0.12 standard units, β = - 0.12, (95% CI: -0.005 to -0.01)

An increase in one week of gestational age was associated with 0.16 increase in LAZ [beta coefficient (β), = 0.16 (95% CI: 0.09 to 0.36)]. However, wasting was 2 times more common among the children born late/post term, AOR= 2.18 (95% CI: 1.25, 3.82, and p = 0.006), compared to children born at term (37-40 weeks).

Conclusions

After rigorous adjustment for confounding factors, post-term pregnancy was associated with a higher risk of thinness but protected against stunting in preschool-age children. These findings suggest that post-term pregnancies may have complex and potentially conflicting effects on the long-term growth and development of children.