[Factors associated with false diagnosis of fetal growth restriction]

The aim of this study was to analize and describe some characteristics related to a false diagnosis of intrauterine growth restriction (IUGR).

We retrospectively included 48 pregnant women referred to our service with a suspected diagnosis of IUGR that was not confirmed after birth and we compared them to another group with confirmed IUGR. We then analyzed the characteristics of the false-positive results. The results of the study were divided into continuous and categorical variables for analysis. The χ2test or Fisher exact test was applied to compare proportions. The level of significance was set at p<0.05 for all tests.

In our sample, pregnant women with a false diagnosis of IUGR had the following characteristics: they were referred earlier (mean gestational age of 32.8 weeks); were submitted to 2 to 6 ultrasound examinations before been registered in our service; in 25% of cases ultrasound examination was performed before 12 weeks; in 66.7% of cases the symphysis-fundal height measurement was normal; in 52.1% of cases they had at least 1 sonographic exam above the 10th percentile; on average, the last ultrasound examination (performed on average at 36 weeks) was above the 18th percentile; the women were submitted to a mean number of 5 ultrasound examinations and to a mean number of 4.6 vitality exams.

The false diagnosis of IUGR involves high hospital costs and higher demand for specialists. The symphysis-fundal height measurement must be valued, and the diagnosis of IUGR must be confirmed with ultrasonography in the last weeks of pregnancy before any obstetric management is taken.