All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Hypoglycemia before conception increases the risk of preterm birth and other adverse outcomes
Last reviewed: 03.08.2025
An analysis of data from more than 4.7 million Chinese women found that women with low blood sugar levels before conception were more likely to experience certain adverse pregnancy outcomes, such as preterm birth or having a low-birth-weight baby.
Hanbin Wu from the Chinese University of Hong Kong, in collaboration with the National Institute of Family Planning Research, reported these results in the open-access journal PLOS Medicine.
Glucose is the body's main source of energy. When blood glucose levels are too high (hyperglycemia, typical of prediabetes and type 2 diabetes) or too low (hypoglycemia), serious health risks can arise.
Previous studies have shown that women with hyperglycemia before or during pregnancy are more likely to experience adverse pregnancy outcomes. The same is true for women with hypoglycemia during pregnancy.
However, few studies have examined the association between pre-pregnancy hypoglycemia and risk in women without diagnosed diabetes.
To shed light on this issue, Wu and his colleagues retrospectively analyzed data from 4,866,919 women in China collected through the National Free Preconception Screening Project, a government program for women planning to become pregnant. The researchers used data from 2013 to 2016 and examined the association between preconception hypoglycemia and pregnancy outcomes.
Hypoglycemia was documented in 239,128 women before pregnancy. Compared with women with normal blood sugar levels, they had a higher risk of a range of adverse outcomes, including:
- Premature birth
- Low birth weight baby
- Congenital malformations
Women with hypoglycemia tended to be younger and more likely to be underweight (lower than normal BMI) than women with normal glucose levels.
However, the risks of adverse outcomes varied by BMI:
- Women who were underweight had a higher risk of miscarriage
- Overweight women had a lower risk of having a baby that weighed more than normal for the gestational age
Based on these findings, the researchers suggest considering hypoglycemia screening before conception to improve the chances of favorable pregnancy outcomes.
Further research may address the limitations of this analysis, such as:
- Inclusion of data from women in other countries
- More information about gestational complications during pregnancy
The authors note:
"In addition to the well-known need to pay attention to women with hyperglycemia before conception, our results highlight the importance of also paying attention to hypoglycemia when screening glycemia in women planning pregnancy.
These findings highlight the importance of preconception screening to prevent and manage reproductive health risks in all women planning pregnancy. They also demonstrate the need for comprehensive screening and coordinated interventions for abnormal fasting glucose (FPG) both before conception and during pregnancy – which is critical to widening the ‘window of intervention’ and reducing the risk of adverse pregnancy outcomes.”