OP01.10: Frontomaxillary facial angle in normal fetuses at 11 + 0 to 13 + 6 weeks in an oriental population

Le résumé fourni par la source

The objective of the study was to establish the normal range of the frontomaxillary facial (FMF) angle of the oriental ethnic origin fetuses at 11 + 0 to 13 weeks gestation. A prospective observational study was performed on 640 cases of singleton pregnancies at the first trimester ultrasound screening between 11 and 13 weeks. Screening for chromosomal defects were tested for by nuchal translucency (NT) measured by doctors accredited in first trimester screening by the Fetal Medicine Foundation, and by maternal serum free human chorionic gonadotropin (free β-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Transabdominal ultrasound examination was performed on a GE Voluson 730 and the FMF angle measured in the midsagittal plane of the fetal profile. Using Fetal Medicine Foundation software to calculate risk, high risk cases (greater than 1/300) underwent fetal karyotyping by chorionic villus sampling or amniocentesis to demonstrate the fetus normal. In a subgroup of 67 cases the FMF angle was measured using 2D ultrasound prior to 3D ultrasound, and then the 3D volumes were used to measure the FMF angle by the same examiner twice and by another examiner once to test repeatability of measurement. The mean FMF angle decreased with crown-rump length (CRL) from 88.1° at CRL 45 mm to 78.3° at CRL 84 mm. There was no significant correlation between the FMF angle and fetal NT or serum PAPP-A or β-hCG, or maternal body weight. In those cases with paired measurements there was no statistical difference between 2D and 3D ultrasound measurement or between measurements that were performed either by the same or by two different sonographers (P > 0.05). This finding demonstrates that our measurements have highly internal and external reliability. This study demonstrates that at 11–13 weeks, the fetal FMF angle reduces with CRL and gestational age but is not related to fetal NT or maternal serum biochemistry.

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