Maternal Weight
Across the world, levels of obesity are increasing. It is estimated that around 2.6 billion people globally – 38% of the world population – are currently overweight or obese, with this percentage looking to increase to over 50% by 2035.
These obesity percentages include women of childbearing age and have sparked debate and research surrounding whether increased maternal weight directly causes pregnancy complications.
Despite research already having been undertaken to establish a correlation between maternal weight and pregnancy complications, it has often been unclear whether the established correlations were due to weight itself or if other factors were at play.
Recent research, led by the University of Bristol and supported internationally, supports the notion that maternal weight and several pregnancy complications are linked, and suggests that supporting expectant mothers to maintain a healthy weight could reduce the risk of various issues.
The Study
Within their study, researchers from the University of Bristol sought to understand the impact of high maternal weight on a wide array of pregnancy-related complications. To measure this, body mass index (BMI) was used, due to the fact it adjusts weight according to height.
The researchers utilised various methodologies, used genetic analyses called Mendelian randomization and brought together research from over 400,000 women and 14 studies from across Europe and North America, to gain a more comprehensive picture in comparison to previous findings.
The Results
The results of the study not only displayed a causal link between maternal weight and pregnancy complications, but also shed light on specific conditions that weight may or may not impact.
A causal link was identified between higher maternal BMIs and 14 out of 20 pregnancy complications included in the study. The complications found to be correlated with higher weight included high blood pressure, pre-eclampsia (where for every kg/m2 increase in maternal BMI, there was a 10% increased risk of pre-eclampsia), pregnancy diabetes and delivery complications including caesarean section, having heavier babies, neonatal intensive care admission and labour induction.
Alongside this, the study found that a higher maternal weight did not appear to influence depression, and that it could also be associated with lower risks of both anaemia and low birth weight.
Outcomes and Next Steps
Given the increasing rates of overweight and obese people across the world, including women of child-bearing age, this research can be said to be significant for several reasons.
Not only does it shed light on the various risk factors and complications that maternal weight may have on a pregnancy, but in doing so it supports the notion that assisting women to maintain a healthy weight could improve pregnancy outcomes. Public-facing policies, physical activity accessibility and promotion and the regulation of consumer marketing could support expectant mothers in maintaining healthier weights and in turn healthier outcomes for themselves and their children.
Despite its potential significance, researchers have made it clear that further studies would be required to uncover a more complete picture. For example, the study found unclear or conflicting results for miscarriage, preterm births and stillbirth rates, suggesting that these would require further investigation to confirm or deny their correlation. It also suggested that larger studies for rare complications and including women from populations outside of Europe and North America were required.
Sources:
News Medical
University of Bristol
