High blood sugar in early pregnancy may slow down fetal growth: Diabetologia

Netherlands: Gestational diabetes mellitus (GDM) is a common complication of pregnancy and affects about 17% of the pregnancies and is associated with adverse maternal and fetal outcomes. Now, a recent study published in the journal Diabetologia has found that higher maternal levels of non-fasting blood sugar levels during early pregnancy may slow down the rate of fetus growth in mid-pregnancy and increase from late pregnancy. This increases the risk of delivering an infant that is large for gestational age.

This implies the need for future preventive strategies that are focused on screening impaired glucose metabolism in mothers from preconception to early pregnancy onwards to improve birth outcomes.

About 17% of the pregnancies are complicated by gestational diabetes that adversely affects birth outcomes. Recent studies have suggested that high maternal blood glucose levels that are below the threshold for GDM. However, not much is known about the direct effects of impaired maternal glucose metabolism from early pregnancy onward on risks of adverse birth outcomes and fetal growth.

Romy Gaillard, University Medical Center Rotterdam, Rotterdam, the Netherlands, and colleagues aimed to assess the associations of maternal early-pregnancy blood glucose levels with fetal growth throughout pregnancy and risk of adverse birth outcomes.

This population-based prospective cohort study involved 6116 pregnant women. Maternal non-fasting glucose levels were measured in blood plasma at a median 13.2 weeks of gestation. Fetal growth was subsequently measured by ultrasound in each pregnancy period. Information about birth outcomes from medical records and maternal sociodemographic and lifestyle factors were obtained from questionnaires.

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Key findings of the study include:

• Higher maternal early-pregnancy non-fasting glucose levels were associated with altered fetal growth patterns, characterised by decreased fetal growth rates in mid-pregnancy and increased fetal growth rates from late pregnancy onwards, resulting in an increased length and weight at birth.


• A weaker association of maternal early-pregnancy non-fasting glucose levels with fetal head circumference growth rates was present.


• Higher maternal early-pregnancy non-fasting glucose levels were also associated with an increased risk of delivering a large-for-gestational-age infant, but decreased the risk of delivering a small-for-gestational-age infant.


• These associations were not explained by maternal sociodemographic factors, lifestyle factors or BMI.


• Maternal early-pregnancy non-fasting glucose levels were not associated with preterm birth or delivery complications.

"Instead of targeting maternal glucose metabolism in the second half of pregnancy as in current clinical practice, future preventive strategies need to focus on screening for an impaired maternal glucose metabolism from preconception and early pregnancy onwards to improve fetal growth and birth outcomes," concluded the authors.