Placental laterality: As a predictor for the development of Pre- eclampsia

Objective: To find whether placental laterality as determined by ultrasound can be used as predictor for the development of pre-eclampsia. Methods: This prospective study was conducted in the Department of Obstetrics and Gynecology, R.N.T. Medical College, Udaipur from 2014 to 2015. 100 pregnant women attending antenatal clinic both OPD and IPD at 20–24 weeks of gestation without any high risk factor were subjected to ultrasound examination, and placental location was determined. These cases were followed for the development of signs and symptoms of pre-eclampsia. Result: Out of the total 100 women, 50 had laterally located placenta and of them, 33 (66 %) developed preeclampsia, while the remaining 50 had centrally located placenta and of them, 18 (36 %) developed preeclampsia. So, the overall risk of developing pre-eclampsia with laterally located placenta was 3.451 (Odds Ratio) and 95% Confidence Interval (1.52 to 7.85). The difference was found to be statistically significant, p value (0.01) by chi-square test. 
 Conclusion: Ultrasonography is simple, non-invasive, easy to perform, cost effective, diagnostic method to identify high-risk cases. From the above study, we concluded that females with laterally located placenta determined by USG at 20–24 weeks of gestation have five times greater risk of developing preeclampsia. By identifying such patients appropriate treatment can be initiated and the patients are regularly followed up. Keywords: Placental laterality, Pre-eclampsia , Central placenta, Predictor I. Introduction Hypertensive disorders remain the most common medical complications during pregnancy and form one of the deadly triad along with hemorrhage and infections. These disorders indeed, remain among the most significant and intriguing unsolved problem in obstetrics. Pre-eclampsia is a disease of trophoblastic tissue. Preeclampsia is a multi-system disorder of pregnancy, which is characterized by new onset hypertension (systolic and diastolic blood pressure of ≥ 140 and 90 mm Hg, respectively, using Korotkoff V sound for diastolic blood pressure recorded on two occasions 6 hour apart with proteinuria (0.3 grams or more protein in 24 hour collected urine sample with 1+ or greater on urine dipstick test) after 20 weeks of gestation involving multiple organ systems in non proteinuric women. Preeclampsia occurs only in the presence of placenta[1]. Several tests have been proposed to identify women at risk of developing preeclampsia. Some of these tests such as the cold pressor test, the isometric hand grip exercise, and the roll over test depend on the presence of some pathophysiological changes that occur in preeclampsia. Other tests such as the measurement of urinary calcium or plasma fibronectin are based on the presence of biochemical alterations peculiar to this disease. Placental location has been found to correlate with fetal position and presentation [2,3], length of gestation[4], course of labor[5], presence of pre-eclampsia[6,7], and pregnancy outcome[8] . Among the various predictors for pre-eclampsia, the placental location by ultrasound at 18–24 weeks is very cost effective, non-invasive, and has a good positive predictive value[9] . There is a significant association between placental location and uterine artery resistance and adverse outcomes such as pre-eclampsia and IUGR. In the women with centrally located placenta, both uterine arteries demonstrate similar resistance. When the placenta is laterally located, the uterine artery close to the placenta has lower resistance than the one opposite from it. In laterally located placenta, the utero placental blood flow needs are to be met primarily by one of the uterine arteries with some contribution by the other uterine artery via collateral circulation [10,11]. The degree of collateral contribution may not be the same in all women, and deficient contribution facilitates the development of pre-eclampsia, IUGR, or both. Placental laterality as a predictor for the development of Preeclampsia DOI: 10.9790/0853-1506130610 www.iosrjournals.org 7 | Page II. Materials and Methods The present study is a hospital based prospective study. This study was carried out in the Department of Obstetrics and Gynecology, R.N.T. Medical College ,Udaipur from the period of October 2014 to 2015. The study was started after proper approval from Institutional Ethical Committee of RNT Medical College, Udaipur Inclusion Criteria All pregnant women attending the antenatal clinic, both outpatient and ward admissions, at 20–24 weeks of gestation without any high risk factors were included in this study. Exclusion Criteria Pregnant women were excluded from the study if they were having chronic hypertension or essential hypertension, Elderly Primi gravida, 
 Twin gestation
 ,Uterine anomalies,
 Previous caesarean section
 ,Previous history of pre-eclampsia or eclampsia, Diabetes
 ,Renal disease,
 Thyrotoxicosis, Connective tissue disorder, Recurrent Pregnancy Loss, 
 History of smoking / alcohol / drug addiction. All the cases were subjected to detailed history, general physical, and systemic as well as obstetrical examination at the time of their antenatal visit and at the time of admission. The location of placenta was determined by ultrasound at 20–24 weeks in all the selected women and followed subsequently for the development of pre-eclampsia. Blood Pressure was measured in sitting posture from right arm by mercury 
 sphygmomanometer for which phase Korotkoff V sound was taken to determine the diastolic component .Urine Albumin determination was done by Urinary Dipstick method in which all samples were Midstream Urine and were collected in a clean sterile container. 
 Dipstick was held horizontally for 60 seconds before reading the result. Pedal edema of the subjects was determined by applying pressure with thumb over medial malleolus of lower limb is either present or absent, and if present either pitting or non pitting. 
 
 The placenta was classified as central when it was equally distributed between the right and left side of uterus irrespective of anterior, posterior, or fundal position. When 75 % or more of the placental mass was to one side of the midline, it was classified as unilateral right or left placenta. All women were followed throughout the pregnancy for the development of the signs and symptoms of pre-eclampsia. Pre-eclampsia was diagnosed on the basis of the American Congress of Obstetricians and Gynecologists criteria for pre-eclampsia. The patients were treated according to the severity of the disease. Mild cases were advised bed rest and prescribed sedatives and told to come for regular follow-ups, while moderate to severe cases were given antihypertensive (labetalol) in addition to the above treatment. Those who showed no response were hospitalized and managed accordingly. In severe cases with persistent hypertension, pregnancy was terminated. III. Results  Out of the total 100 women, 54 women were in the age group 21 to 25 years ,of which 68% had lateral location of placenta (Table 1). Fifty cases had laterally located placenta, while 50 cases had centrally located placenta on ultrasound examination done at 20–24 weeks of gestation . Distribution of cases according to age and placental location (Table 1) Age in years Placental location Central n(%) Lateral n(%)