Correlation analysis of Each Variable of Fetal Heart rate in Pregnancy induced hypertension and Intrauterine fetal growth restriction / 대한산부인과학회잡지

OBJECTIVE: We aim to analyze each variable of FHR in high risk pregnancies, namely intrauterine growth restriction (IUGR) and pregnancy-induced hypertension (PIH) including chronic hypertensive vascular disease (CHVD), mild and severe preeclampsia to build an objective decision basis using correlation analysis. METHODS: The patients were divided into two groups (500 normal pregnancies and 500 high risk pregnancies related to IUGR, CHVD, mild and severe preeclampsia), and then subdivided into intrauterine pregnancy before 24 weeks, 25-39 weeks, and after 40 weeks. We compared the canonical correlation between each group using variables of FHR after nonstress test (NST). RESULTS: In high risk pregnancies, the linearity was 0.6-0.8 in intrauterine pregnancy before 24 weeks, 0.53-0.68 in 25-29 weeks, 0.50-0.60 in 30-34 weeks, 0.38-0.45 in 35-39 weeks and 0.42-0.55 in after 40 weeks. In normal pregnancies, the linearity was 0.44-0.52 in intrauterine pregnancy before 24 weeks, 0.38-0.45 in 25- 39 weeks which was stable, and there was no specific change in after 40 weeks. Before 32 weeks, canonical variates of FHR_D and FHR_I revealed highest (0.36, 0.47 respectively) in high risk pregnancy and fetal movement and signal loss was the most valuable factors in normal pregnancy. In between 33 to 37 weeks, fetal movement (0.40) and signal loss (0.48) were related most closely in high risk pregnancies and 0.34 and 0.49 respectively in normal pregnancies which show similar pattern. In contrast, FHR_D was most highly related to the duration of pregnancy and FHR_I to fetal movement (0.38) in high risk pregnancy. In normal pregnancies, fetal movement (0.40) and signal loss (0.52) showed the highest linearity. CONCLUSION: The pregnancy with intrauterine growth restriction and pregnancy induced hypertension has more linear relation and less complexity in each variable of FHR than the normal pregnancy group. The formal, functional underdevelopment of fetus may results in the increasement of the linear depedent relation in each variable of FHR in these type of high risk pregnancies.

Correlation Analysis of each variable of Fetal Heart Rate Observed through Computerized Monitoring / 대한산부인과학회잡지

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