Body Mass Index Impact and Predictability on Preeclamptic Toxemia

Preeclampsia is a widespread vascular endothelial dysfunction and vasospasm that occurs after 20 weeks’ gestational age and could clinically present as late as 4-6 weeks postpartum. It is clinically defi ned by hypertension and proteinuria, with or without pathologic edema. The global incidence of PET has been expected TO be around 5-14% of all gestations [1-5]. Hypertensive disorders of pregnancy, involving PET, affect up to 10% of gestations worldwide, forming one of the chief causes of maternal and perinatal morbidity and mortality worldwide. Hypertensive disorders of gestation are major contributing factors to prematurity [6-10]. Preeclampsia is a well-known risk factor for future development of cardiovascular disease and metabolic disease in females.

The relationship that obesity raises the risk of PET has been reported for several populations all over the world signifying that this is not a phenomenon limited to western communities.
It is also evident that this relationship is not limited to obese and overweight women because increases in BMI in the normal range is also correlated with a raised hazardous risk of developing PET [21][22][23].
The research study was performed on 400 recruited cases attending the antenatal care unit of Al-Azhar University Hospital  , the patients were categorized into the fi ve research groups (each n=80) according to BMI.
Arterial Blood pressure estimation was performed by measuring systolic blood pressure and diastolic blood pressure using a simple mercury sphygmomanometer on right arm in a comfortable sitting position after 10 minutes of rest. Obstetric ultrasound was done to confi rm fetal viability, gestational age using biparietal diameter (BPD) and femoral length (FL), and to exclude multiple gestation. Full Laboratory investigations.
Follow-up visits: Re-evaluation of the following parameters was done at twenty eight weeks and thirty six weeks of gestation: Body mass index (kg/m 2 ), arterial blood pressure estimation, full Laboratory investigations. If the systolic BP is ≥ 140 mmHg or the diastolic BP is ≥ 90mmHg re-evaluation was performed after 6 hours to confi rm elevated blood pressure. Cases of preeclampsia were diagnosed according to the following criteria: Systolic BP ≥ 140 mmHg or diastolic BP ≥ 90mmHg on two occasions 6 hours apart after 20 weeks of gestation in a woman known not to have chronic hypertension prior to the pregnancy, proteinuria ≥ 0.3 g in a 24-hour urine collection or 2+ proteinuria on qualitative examination or urinalysis, edema and excessive weight gain may be present in preeclampsia but are no longer necessary for the diagnosis of preeclampsia. Table 1 demonstrates demographic data of studied population showing mean and range of age of studied population, residence and socioeconomic level   showing low socioeconomic level 77% to be most of the studied population.     Bar chart demonstrating the mean age of different study groups Group A=27 years, Group B=26.7 years, Group C=27.4 years, Group D=27.6 years, Group E=27.8 years Table 3 demonstrates clearly no statistically signifi cant difference as regards residence among study groups as p value=0.67 Table 4 demonstrates clearly the difference between various research groups as regards socioeconomic levels showing no statistical signifi cant difference p value=0.76 . Table 5 displays the BMI in a comparative manner between various research groups showing statistically signifi cant difference among the groups with a p value <0.001.

Figure 4
The bar chart above demonstrates the mean BMI among the study groups as group A=21.4, group B=27.6, group C=32.8, group D=37.4, group E=42.7. Table 6 displays and demonstrates clearly the incidence of preeclampsia among the study groups showing a statistically signifi cant difference between groups as incidence of PET increases as BMI increases with a p value =0.035. Figure 5 bar chart displays the incidence of PET among various study groups group A=6.2%, group B=7.5%, group C=11.2%, group D=16.2%, group E=20%. Table 7 shows that the relative risk is 2.21 i.e that the risk of PET nearly doubles with increased BMI.          They demonstrated that around one third of the total effect of body mass index on preeclampsia risk is mediated via infl ammation and triglyceride serum levels . They emphasized additionally that infl ammation was a more crucial mediator than triglycerides by analyzing serum levels of C-reactive protein and triglycerides [1,3,7].
Another research prospective study displayed that the risk of     [21,22,25].
In a research published in the AJOG 2009 Wolk R et al., observed the pregnancies of 385 women from the UK and the Netherlands of all the females who were fi rst time mothers and were obese. The research group displayed that obese fi rst-time mothers had an 11.7 % risk of developing PET. In comparison, healthy-weight mothers have a 2 % risk of developing PET. In a research previously conducted of some atherogenic markers in PET had displayed that serum triglyceride, total cholesterol, low density lipoprotein cholesterol and Apo lipoprotein B were statistically signifi cantly higher in PET research group than the normally pregnant group and non-pregnant cases. So a possible correlation might exist between the dyslipidaemia and the occurrence of PET which could agree with our research taking into account the fact that obesity is usually correlated with dyslipidaemia. A population-based research study of 159,072 singleton births in U.S.A. reveled that not only obese women (pre pregnancy body mass index [BMI] ≥ 30.0), but also overweight women (preconception BMI=25.0-29.9) were at a signifi cantly higher risk for preeclampsia (Odds ratio 2.0 and 3.3, respectively) than women with a preconception BMI of less than 20.0 [26,27].
A British population-based research study of 287,213 births demonstrated that the incidence of PET was statistically signifi cantly higher in obese women (pre pregnancy BMI≥30.0; Odd ratio 2.14)as well as overweight women (pre pregnancy BMI=25.0-29.9; Odd ratio 1.44) than in women with a pre pregnancy BMI of 20.0-24.9 .A population-based research of 972,806 births in Sweden clearly demonstrated that obese women (pre pregnancy BMI 29.1-30.0, pre pregnancy BMI 35.1-40.0, pre pregnancy BMI >40) were at a signifi cantly higher risk of developing PET (Odds ratio 2.62, 3.90 and 4.82, respectively) than women with a pre coception BMI of 19.8-26.0 .In multivariable research analysis, obese females (BMI > 29.0 kg/m(2)) had 2.5 times the risk of hypertensive gestation (95% confi dence interval [CI], 1.3-4.8) and 2.7 times the risk of PET development(95% CI, 1.2-5.8), in comparison with women whose BMI was 19.8 to 26.0 kg/m(2). Women with excessive gestational weight gain had a 3-fold increased risk of a hypertensive disorder of pregnancy (95% CI, 1.1-7.2) and a 4-fold risk of preeclampsia (95% CI, 1.2-14.5), in comparison with women achieving optimal weight gain guidelines [28][29][30].

Conclusion
Our research group concluded that increased BMI in this research was correlated with 2.2 fold increased risk of PET than the general population. This risk is confi rmed by that reported in other research studies.