Reference values for the fetal lateral ventricle atrium measurement in the second and third trimesters of pregnancy in a Brazilian population.

Objective: To establish reference values for the fetal atrium lateral ventricle measurements in the second and third trimesters of pregnancy in a Brazilian population.

Methods: A retrospective cross-sectional study was performed with low-risk pregnant women who underwent ultrasound examination at 16-41 weeks of gestation. The atrium of lateral ventricle measurement was performed in the transventricular plane at the end of choroid plexus. We assessed reference curves (percentiles 5th, 50th and 95th) for the atrium of lateral ventricle measurement with gestational age (GA), using the best-fit polynomial equation, and determination coefficient (R(2)) and modeling the variability.

Results: The fetal atrium of lateral ventricle measurements was assessed in 519 singleton pregnancies. However, seven fetuses were excluded because of central nervous system malformations, and therefore data from 512 pregnancies were included in the analysis. The mean ± standard deviation (range) of the fetal atrium lateral ventricle measurement (mm) was 5.1 ± 1.4 (1.6-9.7). A best-fit curve was a first-degree polynomial regression: atrium lateral ventricle = 6.455 - 0.049 × GA (R(2) = 0.05).

Conclusion: Reference values for the fetal atrium lateral ventricle measurements in the second and third trimesters of pregnancy in a Brazilian population were established.