West Virginia Medical Journal - 2022 - Quarter 2 | Page 19

TABLE 1 : Maternal Information Calculated Mean ± Standard Deviations ( 95 % Confidence Interval ) for continuous variables

BMI 35kg / m ² – 39.9kg / m2

BMI ≥ 40kg / m ²

N 796 335 171 154 136 --- BMI ( kg / m ² ) 32.77 ± 8.49 25.22 ± 3.09 32.38 ± 1.48 37.38 ± 1.37 46.66 ± 5.99 <. 01 Weight ( kg ) 89.92 ± 24.54 69.17 ± 1.34 88.48 ± 7.27 103.27 ± 9.56 127.76 ± 2.16 <. 01 Age ( years ) 28.62 ± 5.10 28.16 ± 4.97 28.26 ± 5.31 29.51 ± 5.29 29.21 ± 4.78 0.02 EGA at Assessment 15.97 ± 4.22 16.06 ± 4.08 15.89 ± 4.48 15.95 ± 4.33 15.89 ± 4.14 0.96

BMI = Body Mass Index ; EGA = Estimated Gestational Age

Anova F test p value

TABLE 2 : Fetal Information Calculated Mean ± Standard Deviation ( 95 % Confidence Interval ) for continuous variables

BMI 35kg / m ² – 39.9kg / m2

BMI ≥ 40kg / m ²

EGA Delivered 37.03 ± 2.85 37.19 ± 2.7 37.22 ± 2.45 36.74 ± 3.11 36.74 ± 3.32 0.18

Birth Weight ( grams )

Birth Weight Percentile

3046.10 ± 744.96

3026.32 ± 684.78

3110.87 ± 742.80

3045.34 ± 797.42

3013.98 ± 827.02

58.60 ± 26.61 55.61 ± 26.36 61.75 ± 26.38 60.78 ± 26.98 59.54 ± 26.64 0.05

One-minute Apgar 8.11 ± 1.44 8.22 ± 1.30 8.09 ± 1.27 8.06 ± 1.50 7.90 ± 1.81 0.20 Five-minute Apgar 8.74 ± 1.09 8.79 ± 0.89 8.78 ± 0.83 8.68 ± 1.15 8.61 ± 1.60 0.37

BMI = Body Mass Index ; EGA = Estimated Gestational Age

Anova F test p value

0.62 stitute of Medicine recommendations for the definition of obesity : ⁶ A control group of patients without obesity with a BMI of < 30kg / m ² , BMI of 30kg / m ² – 34.9kg / m ² ( Class I ), BMI of 35kg / m ² – 39.9kg / m ² ( Class II ), and BMI ≥ 40kg / m ² ( Class III ).

Groups were compared using JMP PRO from SAS version 15.1.0 ( Cary , NC , USA ) with the Kruskal-Wallis one-way ANO- VA because the hemodynamic data failed the assumption of equal variances by the Welsh F test . Significance was assumed for a p-value of < 0.05 . The study was approved by the Institutional Review Board at Marshall University ( 1598425-1 ).

RESULTS

Of the 796 patient charts reviewed , 335 had a BMI of < 30kg / m ² , 171 had a BMI of 30kg / m ² – 34.9kg / m ² , 154 had a BMI of 35kg / m ² – 39.9kg / m ² , and 136 had a of BMI ≥ 40kg / m ² ( Table 1 ). The mean maternal BMI was 32.77 ± 8.49 overall . There was a significant difference in the average maternal age at the time of assessment ( p value = 0.0177 ), with the control group having a mean age in years of 28.62 ± 5.10 , Class I 28.16 ± 4.97 , Class II 29.51 ± 5.29 , and Class III 29.21 ± 4.78 . There was no difference in the mean gestational age at the time of impedance cardiography ( ICG ) assessment ( p value = 0.87 ). The only statistically significant difference in the comorbid conditions by BMI category was if the referral reason for hemodynamic testing was type 2 diabetes ( p value = < . 01 ).

Regarding delivery and fetal outcomes ( Table 2 ), there was no significant difference in the estimated gestational age at the time of delivery ( p value = 0.26 ), birth weight ( p value = 0.56 ), birth weight percentile ( p value = 0.0514 ), one-minute Apgar ( p value = 0.10 ), or five-minute Apgar ( p value = 0.29 ).

Comparing BMI across each category , the maternal hemodynamic parameters ( Table 3 ) showed significant differences with respect to systolic blood pressure ( p value < . 0001 ), mean arterial pressure ( p value = 0.0120 ), cardiac output ( p value < 0.0001 ), and systemic vascular resistance ( p value < 0.001 ). As BMI increased , systolic blood pressure and cardiac output increased and systemic vascular resistance decreased . There were no significant differences in maternal heart rate ( p value = 0.2093 ) or diastolic blood pressure between groups ( p value = 0.1139 ).

DISCUSSION

The results of our study indicate that at early gestational ages there are significant differences in systolic blood pressure , mean arterial pressure , cardiac output , and systemic vascular resistance between gravidas with and without obesity . The data indicate that with higher BMI , cardiac output rises and systemic vascular resistance decreases .

Blood volume increases throughout pregnancy until 32-34 weeks gestation , where it peaks at an approximate 40-50 % increase

West Virginia Medical Journal • June 2022 • 17