NEW YORK (Reuters Health) - Two consecutive normal sonograms are enough to exclude fetal overgrowth in women with gestational diabetes, according to a report in the September 23 online Diabetes Care.
Most protocols for monitoring fetal growth during gestational diabetes recommend measurement of fetal abdominal circumference at the time of diagnosis of gestational diabetes followed by repeat examinations every two to four weeks, the investigators say, but it's unclear whether fewer sonograms could suffice.
"With two consecutive ultrasound findings of normal fetal growth, non-large-for-gestational-age neonates of women who had gestational diabetes were predicted with good accuracy," the investigators say. "The predictive ability did not improve with more scans."
Dr. Ute Schaefer-Graf from St. Joseph Hospital, Berlin, Germany, and colleagues wanted to quantify the number of sequential ultrasound examinations needed not to miss the development of fetal overgrowth in a study of 1,914 women with gestational diabetes.
Among a total of 4,478 ultrasound examinations taken between 2001 and 2007, fetal abdominal circumference was at or above the 90th percentile for gestational age in 518 women (27.0%) and was normal in 1,396 women (73.0%).
In the 518 women with abnormal ultrasounds, most enlarged fetal abdominal circumferences (383, 73.9%) were found on the first ultrasound examination, 68 (13.1%) were found on the second sonogram, 33 (6.4%) were found on the third, and fewer on the fourth (20, 3.9%) and fifth (14, 2.7%).
Results were similar for women with and without the need for insulin therapy.
In multivariable regression analysis, independent predictors for development of neonatal macrosomia included history of a large-for-gestational-age newborn, body-mass index above 30, and fasting glucose values above 100 mg/dL.
Among women without these risk factors, there was only a minor increase in the diagnostic rate of newly developed fetal abdominal circumference above the 90th percentile for ultrasound examinations beyond the first two.
A normal ultrasound examination predicted delivery of a non-large-for-gestational-age newborn in 88.9% of women, a probability that increased to 92.2% among women without risk factors for neonatal macrosomia.
The researchers conclude that "limitation to an ultrasound at time of diagnosis of gestational diabetes with 24-27 weeks followed by a subsequent scan at 28-31 weeks might be reasonable especially in women with no risk factors for neonatal macrosomia."
They do however caution that these results need to be confirmed by randomized clinical trials.
Source: http://link.reuters.com/nyc28p
Diabetes Care 2010.
Last Updated: 2010-10-12 11:56:26 -0400 (Reuters Health)
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