Prevalence of subclinical hypothyroidism in North-Indian pregnant women

Abstract

INTRODUCTIONSubclinical hypothyroidism (SCH) in pregnancy is defined by a serum thyroid-stimulating hormone (TSH) concentration higher than the upper limit of the pregnancy related reference range associated with a normal serum thyroxine [T 4; either total (TT 4) or free (FT 4 )] concentration.The prevalence of hypothyroidism during pregnancy is estimated to be 0.3-0.5% for overt hypothyroidism (OH) and 2-3% for subclinical hypothyroidism (SCH).1 There are few reports of prevalence of hypothyroidism during pregnancy from India with prevalence rates ranging from 4.8% to 14.3%. [2][3][4] It is now well established that not only overt but subclinical thyroid dysfunction can also have adverse effects on fetal and maternal outcome. Current data indicate an increase in pregnancy loss, gestational diabetes, gestational hypertension, pre-eclampsia and preterm delivery in women with SCH in pregnancy. The association between SCH in pregnancy and impaired neuropsychological development of the offspring is inconsistent.Many of these adverse effects could be prevented or ameliorated by early detection and appropriate treatment. ABSTRACT Background:It is now well established that not only overt but subclinical thyroid dysfunction can also have adverse effects on fetal and maternal outcomes. In recent years several studies show a much larger prevalence of SCH and marked variation between different ethnic groups. The aim of this study was to find out the prevalence of subclinical hypothyroidism during first trimester in a teaching hospital in North India. Methods: A prospective observational study was conducted in all the consecutive first trimester pregnant women attending Santosh Medical College, Hospital, Ghaziabad from June 2014 to April 2015 after institutional ethics approval and consent from the study subjects. Morning samples of serum were tested for TSH. If serum TSH value was more than 2.5mIU/L then Free T4 and TPO Antibody level were estimated. Results: Serum TSH level was normal in 66.2 % women, 32.5 % women had subclinical hypothyroidism and 1.3 % women had overt hypothyroidism using a first trimester normal reference range of 0.1 to 2.5 mU/l suggested by American Thyroid Association or by the American Endocrine Society. Using 5 mIU/L as upper limit of TSH suggested by some Indian studies serum TSH level was normal in 90.6 % women, 8.1 % women had subclinical hypothyroidism and 1.3 % women had overt hypothyroidism. Conclusion:The prevalence of SCH is very high in our study population. We feel that the use of thyroid function reference values based on studies using different populations and different backgrounds can introduce bias in the evaluation of a local population.

A Clinical Study on Thyroid Dysfunctions in Pregnancy and Its Effect on Maternal and Neonatal Outcome

“…Prevalence was high in age group of 21 -25 years (48.6%) than 26 -30 years' age group (37.5%), and all the study subjects belonged to either poor or lower middle socio-economic status and mean maternal age was 25.4 years. [12] Study conducted by Singh Alpana et al showed that most of the cases were primigravidae; however, there was no statistically significant association between gravidity and thyroid dysfunction. [11] A study conducted by Nirmala C et al showed high prevalence of hypothyroidism in primigravidae (57.7%) and age group <30 years (71.8%) and majority of them belonged to middle class status (57.7%).…”

“…Sci. 2018;7 (12):1520-1523, DOI: 10.14260/jemds/2018/344 BACKGROUND Thyroid dysfunction is a common occurrence in pregnancy and the second most common cause of endocrine dysfunction in the pregnancy after diabetes. Thyroid dysfunctions in pregnancy may be overlooked and underdiagnosed, because of very non-specific and the physiological hypermetabolic state of normal pregnancy.…”

Prevalence of hypothyroidism in term pregnancies in North India

“…Table 1 lists recently published data on this aspect of thyroidology. [ 4 5 6 7 8 9 10 11 12 13 14 15 16 17 ] It must be noted that there is a wide heterogeneity in results, probably due to differing TSH cut offs for diagnosis. Some studies with uncertain or unreliable methodology have not been included in the table.…”