European Journal of Cardiovascular Medicine

Preeclampsia, a multisystem disorder characterized by hypertension and proteinuria with new onset after 20 weeks gestation. It is one of the leading causes of maternal and perinatal morbidity and mortality. In India, Incidence is reported to be 8-10 percent. The aetiology of Preeclampsia currently accepted is the placental ischemia hypothesis, genetic hypothesis, immune maladaptation and hypothesis of oxidative stress. At present, the most popular is the theory of oxidative stress. Abnormal lipid profiles and species may have a role in the promotion of oxidative stress and vascular dysfunction seen in Preeclampsia. [1,2]

Several studies have linked dyslipidemia, characterized by abnormal levels of High-density lipoprotein (HDL), Low density lipoprotein (LDL), Total Cholesterol, Triglycerides (TGL) and Very Low-Density Lipoprotein (VLDL), with an increased risk of Preeclampsia. Altered lipid synthesis leads to an imbalance between vasodilators and vaso-constricting factors, which are important in pathogenesis of Hypertension. [3,4]

Maternal plasma lipids are significantly elevated during pregnancy. Women who develop Preeclampsia experience even more dramatic lipid changes. An abnormal lipid profile is strongly associated with atherosclerotic disease as in Chronic Hypertension. Secondly, elevated plasma lipid levels may induce endothelial dysfunction secondary to oxidative stress and impair trophoblast invasion that lead to the development of Preeclampsia.Though most of case control studies have shown a Preeclampsia-dyslipidemic pattern of increased Triglycerides, Cholesterol, LDL, and decreased HDL, the association of Triglycerides with Preeclampsia was highly suggested to reflect new screening tests. Earlier prospective studies indicate that dyslipidemia, particularly Hypertriglyceridemia and elevated Lipoprotein, precede the clinical manifestation of Preeclampsia and thus may be of etiologic and pathophysiologic importance in this relatively common complication of pregnancy. [3,4,5

Early diagnosis, close antenatal surveillance, and timely intervention are the key to the management of Pregnancy-Induced Hypertension in pregnancy. During the last two decades, a variety of biological, biochemical, and biophysical markers implicated in the pathophysiology of Preeclampsia have been proposed to predict its development. Currently, there are no reliable, economic, and reproducible screening tests that are available, and moreover, the pathophysiologic mechanism of Pregnancy-Induced Hypertension is still not clearly known.The maternal serum Triglycerides measured in early pregnancy are associated with increased risk of Preeclampsia.  Therefore the present study is undertaken for reason as most studies have shown a consistent positive association between elevated maternal Triglycerides and the risk of Preeclampsia. Therefore this study is taken up to identify the significance of the association between the elevated maternal Triglycerides and the risk of Preeclampsia. Inferences from most of the studies are limited by the fact that elevated serum Triglycerides were found after the diagnosis of Preeclampsia.  Therefore this study is done to see if there is any significant elevation of Triglycerides prior to the development of Preeclampsia. Currently there are no clinically useful screening tests to identify development of Preeclampsia and hence this study is taken up to see the effectiveness of maternal Triglycerides as a screening test in the early pregnancy to predict development of Preeclampsia. As many pregnant women from low socio economic group are seen in our hospital setup, doing only maternal serum Triglycerides rather than total lipid profile would be cost effective for the patients and therefore keeping in mind the low socio economic status of the patients, only the study of serum Triglycerides as a marker of positive predictor of Preeclampsia is considered and included for this particular study.

It is Prospective Observational study in Department of Obstetrics & Gynaecology at Vijay Marie Hospital & Educational Society, Hyderabad from November 2014 –August 2015.. Pregnant women in the early second trimester between 13 - 20 weeks registered for antenatal checkup. Total of 300 women were registered.

Average number of patients between the age of 18-35 years were found to be 1300 per year, calculated based on the census of the last 3 years. For a study population of 1300 (finite population) the sample size was calculated using Krejcie & Morgan 1970 Table. The sample size obtained is 297. Convenient sample size of 300 was taken. The same sample size was rechecked using Raosoft online sample size calculator, with confidence interval of 95% and response rate of 50%.

Minimum Sample size was calculated based on following assumptions;

1. Test value of difference in Incidence rates between two groups: 0%
2. Anticipate Incidence rates in both groups43; 25%, 5%.
3. Level of significance: 5%
4. Power of test: 90%
5. Alternative hypothesis one sided test risk difference (P1-P2) : <0%.
6. Using the formula

n =    

                                                                               (P1-P2)2

P1= Anticipated Incidence of Preeclampsia among group II: Increased TGL levels

P2 = Anticipated Incidence of Preeclampsia among group I: Normal TGL levels.

P= P1+P2

       2

Using the above formula, minimal Sample size was calculated, which is 53.

In both study groups, the minimum Sample size is more than 53.

Inclusion Criteria: Women in Age group of 18 -35 years with Gestational age of 13 -20 weeks with any Parity.

Exclusion Criteria: d\Diabetes mellitus, renal disease, liver disorders, pre-existing essential hypertension, pre-existing vascular disease or any endocrine disorder, H/o of treatment with any lipid lowering drugs and epilepsy or any other chronic pre-existing disease.

All pregnant women between 13 – 20 weeks of gestation attending the antenatal OPD at Vijay Marie Hospital were evaluated based on the selection criteria. The selected patients were briefed about the study, details of the test and a written informed consent was obtained. Demographic data like age, socioeconomic status and obstetric history along with relevant medical history was recorded on predesigned and pretested proforma. A detailed history, general physical examination including BMI, obstetric examination was done.

Two ml of venous blood was collected for serum triglyceride level estimation and test was done on same day. Serum triglyceride level estimation was done by enzymatic method with the help of Triglyceride reagent (Agappe diagnostic kit), using GPO-TOPS methodology in an automated analyzer. Serum Triglyceride levels were measured in milligram per deciliter (mg/dL). The level was analyzed and correlated with the rise in blood pressure.

Depending upon the Triglyceride values, these women were divided into two groups.

Group I (control): Pregnant women with S. Triglyceride levels <150 mg/dL.

Group II (study): Pregnant women with S. Triglyceride levels > 150 mg/dL.

During each visit, both systolic and diastolic blood pressures were recorded in these women and diagnosis of PIH was made if systolic blood pressure was >140 mmHg and/or diastolic blood pressure was >  90 mm Hg, taken in the arm in the sitting position with the arm at the level of the heart using a mercury sphygmomanometer. If it was associated with proteinuria with dipstick value of > +1, it was labeled as Preeclampsia as per definition given by National high blood pressure education program (NHBPEP) working group. The pregnant patients were followed throughout the course of pregnancy and development of Preeclampsia was noted.

The data obtained was tabulated on Microsoft Excel Spread Sheet using SPSS 17 software and Descriptive Statistics used. The analysis was done using percentages and the comparison was done using Chi Square test. The data was analyzed as below.

Table-1: Association Of Triglycerides and Preeclampsia

The Incidence of Preeclampsia is 7.8% in this study in Group I: The incidence of Preeclampsia is 20.2% and  Group II: The incidence of Preeclampsia is 3.3%. Mean Triglyceride levels: 133 mg/Dl. There is significant association between Triglyceride levels measured in the second trimester and development of Preeclampsia (P<0.05).

Table-2: Distribution of Patients according to Age between Group I and Group II and Development of Preeclampsia

The association between TGL levels and Development of Preeclampsia is statistically significant among the age group 21- 29 years (P=0.001) and > 30 years (P= 0.01).

Table-3: Distribution of Patients according to Gestational Age between Group I and GroupII and Development of Preeclampsia

The association between TGL levels and Development of Preeclampsia is statistically significant among the Gestational age group 13- 16 weeks (P=0.013) and 17- 20 weeks (P= 0.000059).

Table-4: Distribution of Patients according to Parity between Group I and Group II and

Development of Preeclampsia

The association between TGL levels and Development of Preeclampsia is statistically significant among the Primigravida (P=0.000003) and Multigravida (P= 0.036913).

Table-5: Distribution of Patients according to BMI between Group I and Group II and

Development of Preeclampsia

The association between TGL levels and Development of Preeclampsia is statistically significant among the BMI 18.5 – 24.5 (P=0.001655) and >24.5 – 29.5 (P= 0.009368).

Table-6: Distribution of Patients according to Previous history of PIH between Group I and Group II and Development of Preeclampsia

The association between TGL levels and Development of Preeclampsia is statistically not significant among the patients with Previous history of PIH (P=0.015).

Table-7: Distribution of Patients according to Family history of PIH between Group I and Group II and Development of Preeclampsia

In this study, out of total 280 patients, 11 patients had positive family history, 4 had normal TGL (36.3%), 7 patients had increased TGL (63.6%), 2 patients had Preeclampsia (9%). In this study, Out of total 280 patients, 269 patients had no family history.

The association between TGL levels and Development of Preeclampsia is statistically not significant among the patients with previous history of PIH (P=0.657).

Table-8: Distribution of Patients according to Conception with ART between Group I and Group II and Development of Preeclampsia

In the study, 24 patients conceived with ART procedures, 15 patients had normal TGL levels (62.5%), 9 patients had increased TGL levels (37.5%), 6 patients developed Preeclampsia (25%).

The association between TGL levels and Development of Preeclampsia is statistically not significant among the patients conceived with ART (P=0.465).

Hypertensive disorders are responsible for substantial morbidity for the pregnant woman. They also carry a risk for the baby. Estimation of maternal lipid profile in early second trimester may bring about early recognition of patients at risk of Preeclampsia before the clinical symptoms and complications of Preeclampsia appear for a better feto-maternal outcome. In this study, the measurement of serum Triglycerides has been considered. In this study, out of 280 patients, Total No of patients with increased TGL (>150 mg/dl) were 74 (26.4%). Total No of patients with Normal TGL (<150 mg/dl) were 206 (73.5%) and Total No of patients who developed Preeclampsia: 22 (7.86%). Mean TGL level is 133 mg/dl.  The Incidence of Preeclampsia is 7.8%. P value is < 0.05. There is significant correlation between TGL levels and Risk of Preeclampsia. In a study done by Manjusha Sajith et al[6], out of 1330 pregnant women, 104 patients were diagnosed with Hypertension with prevalence of 7.8%. The prevalence of Preeclampsia was 5.6 %. The Prevalence of Preeclampsia in the present study is comparable to study done by Manjusha Sajith et al[6].

In the present study out of 280 patients, 74 patients had increased triglyceride levels, out of which 15 developed Preeclampsia (20.2%). There is a significant correlation with the level of Triglycerides and risk of Preeclampsia. P value is < 0.05. Enquobahrie et al[3] reported that women who subsequently developed Preeclampsia had 13.6% higher concentrations of Triglycerides, than did control subjects (P <0.05).[7] According to a study done by Kashinakunti et al[7], in the Pre-eclamptic group serum Triglyceride (193.37±43.93 mg/dl) was increased significantly (P<0.001) as compared to normal pregnant women. Vibhuti et al[8] showed that the Triglycerides were higher in Pre-eclamptic pregnant women as compared to normotensive women. The results of the present study are comparable to studies done by Enquobahrie et al[3], Jayante De et al[4], Kashinakunti et al[7], Vibhuti et al[8]. The risk of Preeclampsia is increased with increased Triglyceride levels.

In the 13- 16 weeks gestational age group; Out of total 147 patients, 108 patients had normal TGL levels (73.4%), 39 patients had increased TGL levels (26.5%) and 10 patients had Preeclampsia (6.8%). In the gestational age group 17-20 weeks, out of 133 patients, 98 patients had normal TGL levels (73.6%), 35 patients had increased TGL levels (26.5%) and 12 patients developed Preeclampsia (9.0%). The distribution of patients who developed Preeclampsia is more or less the same with screening in early second trimester. The difference in the two groups based on triglycerides and who developed Preeclampsia is statistically significant (P<0.05) in both the gestational ages 13 – 16 weeks and 17 – 20 weeks. Lorentzen et al[9] concluded that serum-free fatty acids and Triglycerides are increased before 20 weeks of gestation in women who later develop Preeclampsia. Clausen et al[10] concluded that Hypertriglyceridemia-Dyslipidemia before 20 weeks of gestation is associated with the risk of developing early onset Preeclampsia. The present study showed significant correlation or comparable results between gestational age and risk of Preeclampsia.

In the age group <20 years; Out of 39 patients, 26 patients had normal TGL levels (66.6%), 13 patients had elevated TGL levels (33.3%) and 6 developed Preeclampsia (15.3%). In age group 21-29 years; Out of 211 patients, 158 patients had normal TGL (74.8%), 53 patients had increased TGL levels (25.1%) and 13 developed Preeclampsia (6.1%). In the age group > 30 years; Out of 30 patients, 21 patients had normal TGL (70%), 8 patients had increased TGL levels (26.6%) and 3 developed Preeclampsia (10%). Range: 18–35 years. Mean: 24.6 years. SD: + 3.77. The association between TGL levels and Development of Preeclampsia is statistically significant among the age group 21- 29 years (P=0.001) and > 30 years (P= 0.01). KiranYadav et al[7] showed that 51.7 % of cases were in the age group of 25–29 years. Women aged ≥ 40 had approaching twice the risk of developing Preeclampsia, whether they were primiparous or multiparous (RR=1.68, 95% CI 1.23 to 2.29, and 1.96, 1.34 to 2.87, respectively). Liu X et al[11] showed that the risk of hypertensive disorders in pregnancy increased in the age groups above 30 years). The risks of Preeclampsia showed a U-type distribution. The risk was the lowest in the 25-29 age group and the highest in the ≥ 40 age group.  In the present study, there was significant association between the levels of Triglycerides and Preeclampsia among the age groups 21- 29 years and > 30 years and also seen in the studies done by Kiran Yadav et al[12] and Liu X et al[11]. There was no significant association in the age group < 20 years. This may be due to immunological etiology of Preeclampsia in this age group.

In the study, Out of 125 Primigravida, 97 Patients had normal TGL level (77.6%), 28 patients had increased TGL level (22.4%) and 14 patients developed Preeclampsia (11.2%). Out of 155 Multigravida, 109 patients had normal TGL (70.3%), 46 patients had increased TGL levels (29.6%) and 8 patients developed Preeclampsia (5.1%). The association between TGL levels and Development of Preeclampsia is statistically significant among the Primigravida (P=0.000003) and Multigravida (P= 0.036913).  KiranYadav et al[12] showed that out of the 120 cases of the study, 59 (57.84 %) cases were primigravida and 61 (50.8 %) were multigravida. Twelve (57.14 %) cases out of the 21 with PIH were primigravida which suggests that PIH is more common in primigravida cases, and this is similar to that reported by many studies. Gohil et al[13] showed that the obstetric history of subjects in test group as well as control group was studied and it was observed that preeclampsia is significantly more common in primigravida females. Of the 50 preeclamptic subjects included in this study, as high as 60% were primigravida. According to Kirsten et al[13], nulliparity almost triples the risk for pre-eclampsia. Women with pre-eclampsia are twice as likely to be nulliparous as women without pre-eclampsia. The present study correlates with studies done by Kiran Yadav et al[12], Gohil et al[13], and Kirsten et al[14]. There is significant association between the Triglyceride levels and risk of Preeclampsia among the Primigravida and Multigravida but the Incidence of Primigravida (11.2%) having Preeclampsia is more as compared to Multigravida (5.1%) in this particular study.

In the present study, there were no patients in the BMI < 18.5kg/m2. In the BMI group 18.5-24.9 kg/m2, 106 patients, 72 patients had normal TGL (67.9%), 34 had increased TGL levels (32%) and 7 developed preeclampsia (6.6%). In the 25-29.9 kg/m2 BMI group, out of total 149 patients, 118 patients had normal TGL levels (79.1%), 31 patients had increased TGL levels (20.8%) and 12 patients developed Preeclampsia (8%). In the BMI group > 30kg/m2 with 25 patients, 15 patients had normal TGL (60%), 9 had increased TGL levels (36%) and 2 developed Preeclampsia (8%).The association between TGL levels and Development of Preeclampsia is statistically significant among the BMI 18.5 – 24.5 (P=0.001655) and >24.5 – 29.5 (P= 0.009368).

Many studies have shown significant association between increased BMI and risk of Preeclampsia, as seen in study done by Lisa Bodnar et al[15] which reported that Preeclampsia risk rose strikingly from a BMI of 15 to 30 kg/m². According to a metaanalysis study done by Poorolajal J et al[16], Preeclampsia was associated with overweight and obesity.

In a study done by IA Siddiqui and Kashinakunti et al[17], BMI among Preeclamptic and normal women was not significantly different (P= 0.387) (P > 0.05) respectively. Present study showed significant association between TGL levels and Preeclampsia among the BMI groups 18.5 – 24.5 kg/m2, >24.5 – 29.5 kg/m2. The risk of Preeclampsia with increasing BMI cannot be said in this particular study.

In the present study, total number of patients with previous history of preeclampsia is 26. 18 patients had normal TGL levels (69.2%), 8 patients had increased TGL levels (30.7%), 3 patients developed Preeclampsia (11.5%). The association between TGL levels and Development of Preeclampsia is statistically not significant among the patients with Previous history of PIH (P=0.015). In this study, out of total 280 patients, 11 patients had positive family history, 4 had normal TGL (36.3%), 7 patients had increased TGL (63.6%), 2 patients had Preeclampsia (9%). In this study, Out of total 280 patients, 269 patients had no family history. The association between TGL levels and Development of Preeclampsia is statistically not significant among the patients with previous history of PIH (P=0.657). According to Kirsten et al[13], Women who have Preeclampsia in a first pregnancy have seven times the risk of Preeclampsia in a second pregnancy. Women with Preeclampsia in their second pregnancy are also more than seven times more likely to have a history of Preeclampsia in their first pregnancy than women in their second pregnancy who do not develop Preeclampsia. A family history of Preeclampsia nearly triples the risk of Preeclampsia. Women with severe Preeclamptic toxaemia are more likely to have a mother rather than a mother in law who had had Preeclampsia. In the present study, there was no significant association between increased TGL levels and risk of Preeclampsia among the patients with family history of PIH and/or previous history of PIH. Family history and previous history of PIH are a risk factor in development of Preeclampsia but in correlation with Triglycerides there were no significant results in this particular study. Insignificant results may be due to small sample size of the present study.

In the study, 24 patients conceived with ART procedures, 15 patients had normal TGL levels (62.5%), 9 patients had increased TGL levels (37.5%), 6 patients developed Preeclampsia (25%). The association between TGL levels and Development of Preeclampsia is statistically not significant among the patients conceived with ART (P=0.465).According to Miyake et al[18] of the 250 women with PIH, 230 had conceived spontaneously and 20 were ART patients. The 20 ART patients with PIH included 17 IVF patients and 3 ICSI patients. Preeclampsia Incidence was significantly higher with ART. In the present study, the association between TGL levels and risk of Preeclampsia among patients who conceived with ART is not statistically significant. There may be a risk for Preeclampsia in patients who conceived with ART, but in this study the relation to increased TGL levels among that group and risk for Preeclampsia is considered.

The present study was undertaken to study the association of lipid changes particularly Hypertriglyceridemia. There is a significant correlation between elevated Triglycerides and risk of Preeclampsia. In the present study, there are significant results by using Triglyceride levels in the early second trimester as a marker to predict Preeclampsia. With currently no clinically useful screening tests available to identify Preeclampsia, this test can be used as an effective tool for screening of Preeclampsia. The Incidence of Preeclampsia in the present study is 7.8%.

In the present study, there was significant association between Triglycerides and Preeclampsia in relation to factors such as age, Primigravida and BMI. Measuring serum Triglycerides alone appears to be equally effective when compared to total lipid profile.  It is a simple, easy, cost-effective test.

1. As this study is a follow up study, there were drop-out rate of 6%.
2. The level of Serum Triglycerides in a patient may be affected by the ethnicity of the woman which is not considered in the study.
3. In this study, if the patients were simultaneously subjected to another screening test, it would have increased the effectiveness of using only Serum Triglycerides as a screening marker to predict Preeclampsia.
4. Small sample size.

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