medwireNews: Identifying and treating women with gestational diabetes before 20 weeks’ gestation improves their pregnancy outcomes, shows the randomized TOBOGM trial.
The primary pregnancy outcome was a composite of birth before 37 weeks’ gestation, birth trauma, birthweight of 4500 g or more, respiratory distress, the need for phototherapy, stillbirth or neonatal death, or shoulder dystocia.
This occurred in 24.9% of the 378 women in the immediate-treatment group versus 30.5% of the 370 who received treatment at the usual time, giving a significant adjusted risk difference of 5.6 percentage points and a number needed to treat of 18.
The team recruited women registered with antenatal clinics who were between 4- and 19-weeks’ gestation with at least one risk factor for gestational diabetes and sent them for an oral glucose tolerance test (OGTT). This occurred at an average gestation of 15.6 weeks.
The 802 women who had fasting glucose of at least 5.1 mmol/L, 1-hour glucose of at least 10.0 mmol/L, or 2-hour glucose of at least 8.5 mmol/L were randomly assigned either to immediate treatment or for this to be deferred pending the result of a second OGTT at the standard time of 24–28 weeks’ gestation.
Repeat OGTT diagnosed gestational diabetes in 67.0% of the deferred-treatment group, report David Simmons (Western Sydney University, New South Wales, Australia) and co-researchers.
They caution: “This finding raises questions about whether criteria that had been established for OGTT at 24 to 28 weeks’ gestation can be applied to testing early in pregnancy, particularly if there is a potential for harm, such as an increase in the number of small-for-gestational-age births among women who had received early treatment.”
Most individual components of the primary pregnancy outcome favored immediate treatment, with the strongest effect seen for neonatal respiratory distress, which occurred in 9.8% versus 17.0% of infants in the immediate- and deferred-treatment groups, respectively.
This “was the main driver of the between-group difference observed for the first primary outcome,” write the investigators in The New England Journal of Medicine.
They add: “This finding was unexpected because, although respiratory distress is known to occur more frequently in infants born to women with gestational diabetes, its incidence was not shown to be lower in other trials of treatment for gestational diabetes that had been diagnosed at 24 to 28 weeks’ gestation.”
The primary maternal outcome was the incidence of preeclampsia; this occurred in 10.6% of the women assigned to immediate treatment and 9.9% of those assigned to deferred treatment, which was not a significant difference.
Most secondary outcomes were similar between the two groups except for a decreased risk for perineal injury and a shorter stay in the neonatal special care or intensive care unit associated with immediate versus deferred treatment.
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N Engl J Med 2023; doi:10.1056/NEJMoa2214956