The head circumference to chest circumference ratio provided an easy way to detect foetal growth restriction in term...

The head circumference to chest circumference (HC/CC) ratio has been used to identify low birth weight infants in developed countries. This study was conducted to examine whether the ratio could distinguish asymmetrical foetal growth restriction (FGR).

This retrospective observational study was conducted with 1955 infants (50.5% male) born at term between 2016 and 2020 at Tokyo Metropolitan Toshima Hospital, Japan.

We found that 120 (6.1%) had FGR. Their mean birth weight was 3052.1 ± 367.3 g, and their mean gestational age was 39.1 ± 1.1 weeks. Logistic regression analysis showed that the association between the HC/CC ratio and FGR had a regression coefficient of -20.6 (p < 0.000). The linear regression analysis showed that the association between the HC/CC ratio and the birth weight z-score had a regression coefficient of -8.59 (p < 0.000). The coefficient of correlation was -0.33 (p < 0.001). The receiver operating characteristic curve for detecting FGR showed that the area under the curve was 0.75 and the cut-off value was 0.93, with sensitivity of 75.8% and specificity of 60.8%.

Our study established the associations between HC/CC ratio and FGR and birth weight z-scores and confirmed that the ratio provided an easy way to detect FGR in term-born infants.