ABSTRACT
Objective: To investigate the relationship between the Nuchal thickening (NT) and crown–rump length (CRL) in normal Thai fetuses during 10-14 weeks of gestation. Methods: A prospective observational study was conducted. Ultrasound measurement of NT and CRL was offered for 1,000 consecutive Thai fetuses between 10-14 weeks of gestation. Regression analysis was used to analyze the relationship between the NT and CRL. Results: The mean maternal age was 28.03 ± 5.8 yr (range 14-47 yr). The mean CRL was 54.7 ± 12.7 mm (range 10.0-82.0 mm), and the mean NT was 1.6 ± 0.60 mm (range 0.3-6.9 mm), respectively. The median gestational age was 12.0 weeks. The regression equation relating median NT to CRL was described as follows: expected Nuchal thickening (mm) = 0.437 + (0.01764 × CRL) (mm) (R2 = 0.134, p <0.001). Conclusion: The present study offers normative data of the fetal NT in Thai fetuses, which may improve the performance of NT measurement during the first-trimester as a screening tool for chromosomal abnormalities or other congenital abnormalities in the first trimester. The present study shows that NT measurements increase with increasing CRL.
ABSTRACT
A prospective cross-sectional study was conducted in order to construct reference centile charts for tibia and fibula bone length of Thai fetuses. A total of 621 normal pregnant women, who attended the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited between 12 and 41 weeks of gestation. We identified pregnant women who had regular menstrual period for at least 3 months without contraception prior to the current pregnancy; and whose uterine size at the time of examination was compatible with menstrual age. Each fetus was measured only once at a randomly assigned gestation age specifically for the purpose of this study. A total of 461 fetal tibia and fibula lengths were measured due to unfavorable fetal position in some cases. Regression models were fitted to estimate the mean and standard deviation for each parameter at each gestational age. The centile charts of both lower limb lengths for Thai fetuses were derived from regression equations and are presented.
ABSTRACT
A cross-sectional study was conducted in order to construct a reference chart for Thai fetal upper extremities long bone (humerus, radius, and ulna). A total of 621 normal pregnant women, who attended the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited between 12 and 41 weeks of gestation. We identified pregnant women who had previous regular menstrual period for at least 3 months without contraception prior to current pregnancy; and uterine size at the time of examination was compatible with menstrual age. Each fetus was measured only once at a randomly assigned gestational age specifically for the purpose of this study. Due to unfavorable fetal position in some cases, data were available in only 482 measurements of the humerus, and 443 measurements of the radius and ulna respectively. Linear regression models were fitted separately to estimate the mean and standard deviation at each gestational age for each parameter. New reference centiles were constructed from both equations, assuming the data were normally distributed. This will provide more reliable reference data to be utilized in the assessment of gestational age and in the diagnosis of upper limb deformities during fetal period.