Background: Ultrasound biometry of the foetus is now the gold standard for assessing foetal growth and wellbeing. Biparietal diameter, head circumference, femur length, and abdominal circumference are commonly employed; also transverse cerebellar diameter is currently being used in assessment of the gestational age. Ratio of some of these foetal biometry such as HC/AC, BPD/AC, and FL/AC has been used to evaluate foetal growth and well being. TCD/AC ratio has been shown to be an accurate gestational age independent parameter in detecting small for gestational age or intrauterine growth restriction. Studies on normal TCD/AC ratio across the gestational age are scanty in Nigeria.
Aim: To derive population specific TCD/AC ratio for the assessment of normal foetal growth.
Matrial and Method: This was a prospective observational study of 450 healthy singleton pregnant women between 13-42 weeks gestation referred to the Radiology Department of University of Benin Teaching Hospital Benin City. A 3.5 MHz curvilinear transducer of SONOACE X6 machine was used to measure the foetal TCD and Abdominal circumference. GA was determined using the foetal biometric parameters such as BPD, FL, and AC. The TCD/AC ratio was calculated by dividing the TCD by the AC and then multiplying by 100.
Result: The TCD/AC ratio assessed in this studied population is from gestational age of 13weeks to 42weeks. The TCD/AC ratio was fairly constant across the GA with a mean of 13.54 ± 0.58. In the first trimester mean ratio was 13.22 ± 0.39, while 13.36 ± 0.66 and 13.71 ± 0.44 were recorded for the second and third trimester respectively.
Conclusion: A population specific normal standard value is required for proper assessment of foetal growth which can be compared with those foetuses with intrauterine growth restriction (IUGR). The TCD/AC ratio in this study was fairly constant across gestational age with a mean value of 13.54 ± 0.58.
Impact Factor
2022: 6.012
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