Story at a glance
- People who are underweight or overweight and have had a miscarriage may be at higher risk of successive miscarriages.
- Researchers compiled data from several studies to estimate this risk.
- Underweight and overweight people have increased risk of having another miscarriage.
A new study examines the risks of successive miscarriages for people who are either underweight and overweight. The researchers looked at the data for miscarriages in pregnant people who are underweight, defined as having a body mass index (BMI) less than 18.5; and pregnant people who are overweight, defined as a BMI between 25 and 30; and obese with a BMI above 30.
The paper, published in Scientific Reports, details how the researchers reviewed previously published studies and conducted a meta-analysis, meaning they collated and analyzed data from several studies.
“Our study included sixteen studies and showed that being underweight or overweight significantly increases the risk of two consecutive pregnancy losses,” said Bonnie Ng, who is first author on the study and a MRC Fellow in Clinical and Experimental Sciences at the University of Southampton in a press release. “For those with BMI greater than 25 and 30, their risk of suffering a further miscarriage increases by 20% and 70% respectively.”
The researchers found that underweight people had increased risk of recurring pregnancy loss (RPL) compared to the general population, but did not have a greater risk compared to the rest of the RPL population. However, the study results vary and further studies are necessary.
Overall, the findings of this study suggest that having an above- or below- average BMI exacerbates a person’s risk of suffering from repeated miscarriages, and so clinicians really need to focus on helping them manage this risk factor, said Ying Cheong, Professor of Reproductive Medicine at the University of Southampton and senior author of the paper, in the press release.
The researchers state in the paper that the quality of the evidence was low or very low, suggesting the need for better, more comprehensive studies. The team also looked at other risk factors, like smoking and consumption of alcohol and drugs. However, they weren’t able to draw any conclusions because the studies were too small or there were inconsistencies in its results. The team thinks that further data collection and more large-scale studies are needed to understand the connection and risk involved.
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