A new study has shown that under-weight and overweight women are at a significantly higher risk of experiencing recurrent miscarriages compared to those of average weight.
A research team led by the University of Southampton assessed the link between women’s lifestyle and risk of recurrent pregnancy loss, defined as women having two or more consecutive early miscarriages. The systematic review and meta-analysis study has been published in the journal Scientific Reports[1].
Miscarriage is the most common complication of early pregnancy, affecting between 15% and 20% of all pregnancies. Recurrent pregnancy loss is a complex disease and although often attributed to numerous medical factors and lifestyle influences, the cause is deemed “unexplained” in around 50% of cases.
Our findings suggest that having an abnormal BMI exacerbates a woman’s risk of suffering from repeated miscarriages.
The results of this latest study found that there are higher occurrences of successive miscarriages in mothers who are underweight (having a Body Mass Index score of less than 18.5), overweight (having a BMI between 25 and 30) and obese (having a BMI above 30).
The study’s first author, Dr Bonnie Ng, MRC Fellow in Clinical and Experimental Sciences at the University of Southampton said: “Our study included sixteen studies and showed that being underweight or overweight significantly increases the risk of two consecutive pregnancy losses. For those with BMI greater than 25 and 30, their risk of suffering a further miscarriage increases by 20% and 70% respectively.”
The research team also set out to assess the impact of factors such as smoking and consumption of alcohol and caffeine. However, they were unable to establish conclusively whether these have any impact or not due to inconsistencies of the results from a small number of studies and heterogeneity in women taking part in them.
Whilst recognising that more observational and clinical research is needed to establish the full extent of lifestyle choices, the authors conclude that weight is a risk factor that can be modified to reduce the risk.
“Our findings suggest that having an abnormal BMI exacerbates a woman’s risk of suffering from repeated miscarriages, and so clinicians really need to focus on helping women manage this risk factor,” said Ying Cheong, Professor of Reproductive Medicine at the University of Southampton and senior author on the paper.
Reference:
Ka Ying Bonnie Ng, George Cherian, Alexandra J. Kermack, et. al.
Systematic review and meta-analysis of female lifestyle factors and risk of recurrent pregnancy loss. Scientific Reports Vol 11, Article number: 7081 (2021).
doi: https://go.nature.com/3kKHVWm
