Can early evaluation of ‘routinely assayed TSH’ predict the risk of preeclampsia?

 

 

Abstract               Objectives: To study the potential of cost effective and routinely assessed TSH in preeclampsia in the South Indian rural population. Methodology: This is a cross-sectional study with 30 patients of preeclampsia and 30 normotensive gestational age matched healthy controls, blood samples from participants were analysed for TSH and LDH. Results: Our study showed a higher prevalence of hypothyroidism in preeclampsia when compared to controls, preeclampsia patients with hypothyroidism showed a significantly elevated LDH when compared to those with normal serum TSH. Conclusions: Our study indicates that women with preeclampsia show a higher incidence of hypothyroidism, hypothyroidism may be related to improper placentation and development if hypertension in pregnancy. Being an affordable and easily accessible marker, it can be used as a predictor and risk assessor of preeclampsia, of validated by multicentric prospective studies and more studies of such accessible markers should be carried out to design an effective screening panel in a rural and sub urban dominant Indian population.

Key Words: ANC check-ups, Eclampsia, LDH, Maternal mortality, Preeclampsia, TSH.

 

INTRODUCTION

The fifth Millennium Development Goals pledges commitment to achieve 75% reduction in maternal mortality and universal access to reproductive health.^1,2 Despite the progress made in medical science, approximately 800 women die around the world every day from preventable causes related to pregnancy and childbirth (20% from India).³ Haemorrhage, infections, hypertensive disorders (preeclampsia and eclampsia) account for 80% of all maternal deaths.⁴ Globally, preeclampsia is a leading cause of maternal and infant illness and mortality claiming upto 76,000 maternal and 5,00,000 infant deaths per year, according to conservative estimates.⁵ India reports a preeclampsia incidence of 8 – 10 %.⁶ Preeclampsia is a pregnancy specific syndrome that can affect every organ system. It is a rapidly progressive condition characterised by increased blood pressure (140/90 mm Hg), with fluid retention and proteinuria that occurs after 20 weeks of gestation.⁷ Nulliparity, multifetal gestations, obesity, diabetes mellitus, maternal age above 35 years etc predispose to preeclampsia.⁸ The condition becomes further challenging and enigmatic since it often develops without noticeable symptoms and shows a sudden and acute onset. A delay in diagnosis can lead to serious and even fatal complications for both the mother and the baby including IUGR, IUD, preterm birth, placental abruption, HELLP syndrome, eclampsia and severe damage to major organs like liver and kidneys and even death warranting markers for effective diagnosis, management and desirable maternal and foetal outcomes. Once called “the disease of theories”, a lot of breakthroughs have been made in an attempt to search for the causes and markers of preeclampsia, in the recent times. Current research on this subject aim to evaluate the role of hormones, proteins, enzymes and metabolites produced or the levels altered in preeclampsia and the early predictive values of the potential markers.⁵ Though a lot of novel and promising signalling markers, angiogenic and growth factors have been proposed, yet none has been implemented into routine and widespread clinical practice for early risk assessment and diagnosis of preeclampsia. This could be due to shortcomings in translation of these markers into the routine laboratory analytical platform and the associated high expenses. In a developing country like India, with a huge rural population, social norms and socio-economic factors often affect the accessibility to health care services. Further, their low economic status and ignorance lead to non-compliance to visiting ANC clinics for regular check-ups, to the medications prescribed and tests ordered. Hence the need of the hour is the investigation of easily accessible and affordable markers and screening panels for risk assessment which could be cater to and could be effectively implemented especially in our resource and technology constrained rural and sub urban setups.This report based on our ICMR STS project “A cross sectional hospital based study of serum TSH, LDH and uric acid in preeclampsia and normotensive pregnant women” presents excerpts of the findings of our study and aims to highlight the promise and importance of the routine assayed biomarkers in prediction and diagnosis of preeclampsia.

 

MATERIAL AND METHODS

The study is a cross sectional study carried out in 60 women admitted to the Department of Obstetrics and Gynaecology in MVJ Medical College and Research Hospital. 30 women with preeclampsia constituted the case group. 30 normotensive gestational age matched pregnant women admitted to the antenatal ward participated as controls. Ethical approval was obtained from the Institutional Ethical Committee and an informed consent was taken from all the participants of the study. Blood samples collected from the study participants were assayed for TSH (ECLIA) and LDH (DGKC) in the Clinical Biochemistry Laboratory of MVJ Medical College and Research Hospital.

 RESULTS

The preeclampsia group had 16 cases of mild preeclampsia and 14 cases of severe preeclampsia. Figure I and Figure II show the percentage of participants having elevated TSH in control and cases group and it is clearly seen that the preeclampsia group had a substantially higher percentage of women with hypothyroidism.

Further, we observed that a large proportion of these patients were unaware of their hypothyroid status throughout their gestational period and hence received no supplementation or treatment for the same, either due to non-attendance to antenatal check-ups in the early gestation or failure to comply to the physician ordered tests which might have aggravated and worsened their adverse outcomes pertaining but not limited to preeclampsia alone. Further, LDH (marker of tissue anoxemia and anaerobiosis) was measured in preeclampsia patients. The serum LDH in patients with normal thyroid function was lower when compared with LDH in patients with elevated TSH levels and difference was found to be statistically significant showing a P value of 0.04 (Table I).

 

              Figure I: Pie chart showing TSH levels in control group                         Figure II: Pie chart showing TSH values in preeclamptic group