Friday, September 14, 2012

Study variables

Study variables. The study variables included both biometric measurements and evaluation of morphologic features. The biometric measurements assessed were gestational sac dimensions, crown-rump length (CRL), biparietal diameter (BPD), and thoracoabdominal diameter (TAD). The morphologic features evaluated included: presence of fetal heart activity, the 4 chambers of the heart, great vessels, axial and appendicular skeleton, thorax, abdomen, and brain.


Statistical analysis. Continuous variables including CRL, BPD, GA, and sac dimensions were checked for normality by use of the Wilk-Shapiro test, and no significant skewness or non-normality was detected. The Pearson product-moment correlation (r) was used as the measure of linear association. Least-squares regression was used to fit equations for predicting GA from BPD and CRL, with the coefficient of determination (R2) used to interpret the proportion of the variability in GA accounted for by each biometric measurement. We used 2-tailed values of P < 0.05 to indicate statistical significance. Regression modeling and data analysis was performed by use of the SAS software package (version 8.0, SAS Institute, Cary, NC). There are always plenty of opportunities to save money without having to sacrifice any of the quality, and the very existence of our pharmacy is the best example. Сanadian healthcare shop gives you FDA-approved medications for any condition you may have, and the prices are very appealing, no matter how much you were going to spend.



Figure 3. Crown-rump measurements and gestational age. (A) 10.5 DPC, 3.0 mm. (B) 12.5 DPC, 7.0 mm. (C) 13.5 DPC, 9.0 mm. Biometric measurements correlated well with GA. (D) Axial image of fetal skull shows BPD of 3.5 mm at 13.5 DPC.

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