Title: Validity of midtrimester serum beta HCG in predicting pre eclampsia in high risk pregnancies
Abstract: INTRODUCTION: Preeclampsia is a multisystem disorder of pregnancy and puerperium of unknown
aetiology and characterised by Hypertension and Proteinuria. It is one of the major causes of maternal and perinatal mortality and morbidity. It complicates 5 – 8% of pregnancies. The underlying pathophysiological mechanisms responsible for the disease process seem to appear between 8 and 18 weeks of gestation (Robertson & Khong, 1991). But the signs and symptoms become apparent in relatively late stages of pregnancy. So it is logical to search for predictive indicators. Measurement in early pregnancy of a variety of biological, biochemical and biophysical markers implicated in pathophysiology of preeclampsia has been proposed to predict its development. Investigators have attempted to identify early markers of faulty placentation, reduced placental perfusion, endothelial cell dysfunction and activation of coagulation system. Attempts thus far have resulted in testing strategies
with poor sensitivity and poor positive predictive value for preeclampsia. Currently there are no screening tests for preeclampsia that are reliable, valid and economical. AIM OF STUDY: 1. To estimate Serum β hCG levels in early 2nd trimester in a population of high risk Multigravid women. 2. To study any positive correlation between elevated serum βhCG and the development of preeclampsia. MATERIALS AND METHODS:
Study design: Prospective case control study.
Study place: Institute of Obstetrics and Gynaecology, Egmore, Chennai.
Study period: April, 2007 – April, 2008.
This study was conducted in 200 cases of high risk multi gravid women attending
outpatient department of Institute of Obstetrics and Gynaecology, Chennai.
This study was approved by the board of ethical committee.
METHODOLOGY:
200 cases of high risk multigravid women attending outpatient department of IOG
with normal blood pressure and normal urine examination of gestational age 15 – 20
weeks were taken for the study after obtaining informed consent. The high risk factors
included in the study were previous history of preeclampsia remote from term(< 34
weeks), recurrent spontaneous abortions (2 or more), previous still births, accidental
haemorrhage, IUGR, eclampsia. Detailed history and physical examination including
blood pressure, urine examination, and abdominal examination were done. Other
baseline investigations like Hb, PCV, blood sugar, USG were done to rule out anaemia,
diabetes, multiple pregnancies, anomalous babies and wrong dates. About 5 ml of
venous blood was taken at 15 to 20 weeks gestation and serum βhCG estimated by
ELISA method using Chemiluscence technique. Patients were divided into two groups
based on their serum βhCG values – 1) those with elevated serum βhCG (≥2 MOM) 2)
those with normal serum βhCG values (<2 MOM). Both groups of patients were
followed up fortnightly up to 28 weeks and then weekly till delivery. During each visit
general examination including blood pressure recording, urine examination for sugar
and protein, abdominal examination to assess foetal growth & wellbeing and liquor
status were done.
To ensure accurate reading of blood pressure and appropriate size BP cuff was
used (12 x 23 cm for normal size arm and for arm size more than 35 cm cuff size 15 x
33 cm). BP was recorded after a rest period of 10 min., with the patient in sitting posture
with the arm at the level of heart.
The results were analysed using Chi-square and two sample t test using SPSS version 11.5 software.
Inclusion Criteria:
Multigravid women with previous history of
i. PIH remote from term (less than 34 weeks),
ii. Recurrent spontaneous abortion (two or more),
iii. Still birth,
iv. Accidental haemorrhage,
v. IUGR,
vi. Eclampsia.
Exclusion Criteria:
a. Gestational age 20 weeks,
b. Women with Chronic hypertension,
c. Other medical disorders complicating pregnancy such as Diabetes, Anaemia,
Thyroid, SLE.
d. Multiple pregnancies,
e. Babies with suspected or confirmed congenital anomalies detected by USG.
SUMMARY: This study was conducted in 200 cases of high risk multigravid women to evaluate
the validity of midtrimester serum βhCG in predicting preeclampsia.
• Majority of women in this study were in the age group of 21 – 25 years (49.5%) and
of socioeconomic class v (82.5%)
• Majority of women were second gravidae (56.5%).
• The average gestational age at which serum βhCG was taken was 16 weeks.
• Of 106 cases with elevated serum βhCG (≥2 Multiples of Median), 76 cases (71.7%)
developed preeclampsia. This is in contrast to 94 cases with normal HCG values, of
whom 18cases (19.9%) developed preeclampsia. This is statistically significant with
P value < 0.001.
• Preeclamptic patients with elevated serum βhCG values developed preeclampsia
significantly earlier (average 34.97 weeks) in gestation than preeclamptic patients
(36.16 weeks) with normal serum βhCG values.
• Out of 106 patients with elevated serum βhCG values 9 patients developed
complications as compared to 94 patients with normal serum βhCG values of which
only 2 patients developed complications.
• Patients with elevated serum βhCG values also had significantly earlier deliveries
and lower birth weight babies when compared to normal serum βhCG group.
CONCLUSION:
Preeclampsia is a multisystem disorder of unknown aetiology. Although many
predictors have been put forth none of the methods so far described have been very
much sensitive and specific to predict the development of preeclampsia. Predicting
preeclampsia at an early gestational age helps us to monitor the patients closely and
detect development of preeclampsia earlier and thereby reducing the maternal and
perinatal mortality and morbidity. Estimating midtrimester (15 – 20 weeks) serum βhCG
is a useful method in predicting preeclampsia in high risk multigravid women as it is a
non invasive simple method with sensitivity of 80.85%, specificity of 71.7%, positive
predictive value of 71.7% and negative predictive value of 80.85% , the diagnostic
accuracy of the test is 76% (Wilson’s score). The disadvantage of using serum βhCG in
predicting preeclampsia is its cost and low sensitivity in nulliparous women.
Publication Year: 2009
Publication Date: 2009-03-01
Language: en
Type: dissertation
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