Outcome of clinical hypothyroidism in pregnancy: a case control study

Abstract

INTRODUCTIONThyroid gland dysfunctions in the form of hypo or hyperthyroidism have been known to have a deleterious effect on fertility as well as pregnancy. The various hypofunction thyroid disorders encountered in pregnant women are clinical or clinical and subclinical hypothyroidism. Pregnancy itself modifies thyroid gland functions in the form of 50% increase in thyroxine (T4) and triiodothyronine (T3) production, decreased levels of thyrotropin (TSH) due to effect of human chorionic gonadotropin and 50% increase in daily iodine requirement.1 Clinical hypothyroidism is defined as decreased free thyroxine levels with an increased value of thyrotropin (>2.5miu/L). This has been associated with increased incidence of gestational hypertension and diabetes, preterm delivery and Caesarean section in pregnant women.2 This study is undertaken to find out the effects of adequately treated clinical hypothyroidism in pregnancy when compared with pregnant euthyroid controls. METHODSThis study was conducted in a tertiary care centre over a period of one year and 144 cases of clinical hypothyroidism in pregnancy were taken into account who formed the case group. Inclusion criteriaNewly diagnosed clinical hypothyroidism in pregnancy, TSH>2.5 mIU/L in 1 st and 3mIU/L in the 2 nd and 3 rd trimesters respectively according to American thyroid association guidelines. ABSTRACTBackground: Hypothyroidism in pregnancy is generally associated with various adverse outcomes. Also worldwide, there is an increased awareness about morbidity caused by this endocrinological disorder in pregnancy .This study is undertaken to evaluate the outcome of this condition in pregnancy. Methods: 144 newly diagnosed clinical hypothyroid pregnant women were taken as the case group and 145 age and parity matched euthyroid pregnant women were taken as controls. The outcome compared in between these two groups were pregnancy complications like gestational diabetes and hypertension , oligohydramnios, intrauterine growth restriction , intrauterine demise, Caesarean section rates and it's indication as well as neonatal outcome like birth weight and need for neonatal intensive care.Results: Clinical hypothyroidism in pregnancy constituted 6.1% of the total number of deliveries. There was a significantly higher number of gestational diabetes in the case group (p=0.0001). Caesarean sections done for the indication of foetal distress was significantly higher when compared with the control group (p=0.00002). Large for gestational age babies were more common in case group. Conclusions: Clinical hypothyroidism in pregnancy even when treated adequately might lead to complications.