ABSTRACT
OBJECTIVE: We aim to analyze each variable affecting FHR to build objective decision basis using canonical correlation analysis METHODS: The sixty four hundred and fifty five cases of NST from 1988 to 1997 at Hanyang University hospital were collected. We used FHR interpretation softwares, HYFM-I & II those were already developed by author, for extraction of each variable of FHR. We classified the variables into 2 groups, F.A.M(FHR, Amplitude, Mean minute range) and N.S.F(NST weeks, Signal loss, Fetal movement) groups. The Canonical correlation was compared between each variable and group. RESULTS: The canonical correlation between F.A.M & N.S.F are as follows; r=0.40 (p=0.001) in preterm, r=0.34 (p=0.001) in term, and r=0.41 (p=0.004) in postterm. The high linear dependency is shown as r=0.79 (p=0.013) before 23 weeks, the irregular changes shown from 23 weeks to 30 weeks (r=0.47 in 23-24 weeks, r=0.29 in 25-26 weeks, r=0.56 in 27-28 weeks, r=0.24 in 29-30 weeks) and the stable relative changes shown (about r=0.3-0.4) after 30 weeks (r=0.32 in 31-32 weeks, r=0.33 in 33-34 weeks, r=0.37 in 35-36, r=0.33 in 37-38 weeks, r=0.37 in 39-40 weeks, r=0.35 after 41 weeks) (p<0.02). In the linear correlation of FHR, two indicies of FHR variables, AMP and MMR pertaining to N.S.F., FHR(r) is 0.06, AMP and MMR seem to be identical as r=0.30 and then the canonization in term and postterm[FHR(r)=-0.27, AMR(r)=0.23, and MMR(r)=0.35]lies in the regular pattern. Moreover, there is rather a linear correlation between F.A.M and the gestational weeks in preterm and it is changed into linearity similar to zero in term and postterm pregnancies[term(r)=0.01, postterm(r)=0.06] CONCLUSIONS: This study shows the linearity of FHR and the variable which are based on the gestational weeks organically, comprehensibly, and quantitatively. It would be utilized as the fundamental standard of the linearity. The changes from the irregular linear correlation to the regular pattern according to advancing gestational weeks means the changes from the immature and transitional level to the mature level. The closer investigation of the linear and