Assessment of fetal growth using the ratio of the transverse cerebellar diameter to abdominal circumference.

OBJECTIVE

To evaluate use of the transverse cerebellar diameter to abdominal circumference (TCD/AC) ratio in predicting intrauterine growth restriction (IUGR).

METHODS

A prospective observational study was conducted at a prenatal clinic in Udaipur, India, between August 2011 and December 2012. Women with a singleton pregnancy and a confirmed gestational age of 20-36 weeks were enrolled. Transverse cerebellar diameter and abdominal circumference were measured by ultrasonography on two prenatal visits at early (20-28 weeks) and late (30-36 weeks) gestation. A TCD/AC ratio above the 90th percentile was considered to indicate IUGR. Birth weight was recorded.

RESULTS

Overall, 100 women completed the study. Among 15 neonates with IUGR, the mean TCD/AC ratio was 14.17 ± 0.89 at early gestation and 15.61 ± 1.18 at late gestation. The TCD/AC ratio for appropriate-for-gestational-age neonates was significantly lower: 13.50 ± 0.97 and 13.80 ± 0.97 at early and late gestation, respectively (P<0.05 for both). Among 14 fetuses with a TCD/AC ratio above the 90th percentile at early gestation, 9 (64%) were small for gestational age, 5 (36%) were appropriate for gestational age, and none was large for gestational age at the neonatal examination.

CONCLUSION

The TCD/AC ratio was fairly accurate in recognizing abnormal fetal growth at an early gestational age.