Poverty is known to be associated with poor health outcomes throughout life. Now, new research has shown that, from as early as the second trimester of pregnancy, fetuses are already feeling the effects of poverty.
“There is a well-recognized health inequality where quality and duration of life are lower among the most poor. This divide is present both within and between countries,” said Steve Turner, who led the study.
Given the association of poverty and low birth weight, the authors of the new multi-national study, published in the Journal of Epidemiology and Community Health, hypothesized that “individuals from highest household income compared to those with lowest household income will have increased fetal size in the second and third trimester and birth.”
For their study, researchers from the University of Aberdeen gathered details of ante-natal and birth size – second and third trimester fetal ultrasound measurements of estimated fetal weight, biparietal diameter, and femur length, as well as birth measurements of weight, occipitofrontal circumference, and crown heel length – from eight cohorts that included 21,714 individuals from nations including Scotland, England, Saudi Arabia, the U.S., Netherlands, Spain, Norway, Sweden, and France.
They then related these to household income, taking into account other factors, including mother’s age, height, number of other children, and smoking, analyzing the data using cross-sectional two-stage individual patient data analyses and a longitudinal one-stage individual patient data analysis.
Household income closely related to birth size
The authors found that higher household income was associated with larger fetal head size and weight but not length, from the second half of pregnancy, compared with lowest household income. They said that their results argue for “a relationship where household income is closely related to birth size.”
The results showed that, across the countries studied, babies were smaller at birth if they came from a lower income household, and this discrepancy in size was already apparent at 20 weeks gestation.
“This is the first time that size differences have been found at such an early stage of development,” the authors said, “and also the first time it has been compared across continents.”
Professor Turner pointed out that “what this study shows is that the inequality, as seen by reduced size in fetal life, is present long before birth, and this poverty gap widens between twenty weeks gestation and birth.”
He added: “Basically, regardless of whether you live in Saudi, the U.S., or Europe, and accounting for things that might affect fetal growth, if your parents are poor, you will be smaller before birth and at birth compared to if your parents were not poor.”
Increase engagement with pregnant mothers living in poverty
He emphasized how this was problematic, as small size before and after birth puts an individual at “increased risk for many serious illnesses in later life.”
The authors hope that this study will encourage health care providers to recognize the health risks associated with lower income for mothers and their unborn children and to provide more support and guidance to mitigate the risks.
They said, “interventions aimed at softening the impact of poverty on pregnant mothers could reduce incidence of small for gestational age and the associated burden of excessive morbidity and mortality throughout the life course.”
Professor Turner described how the mechanisms that drive this inequity may be explained by pregnant mothers from poor households having difficulty in accessing or engaging with antenatal care.
“We would like to see health care providers around the world strive to increase engagement with pregnant mothers living in poverty,” he said. “This engagement will reward all of society by putting unborn children on a trajectory to longer and healthier lives.”
A version of this article first appeared on Medscape UK.