Exploring the association between thyroid dysfunction in pregnancy and Gestational diabetes mellitus

Thyroid dysfunction and gestational diabetes present notable challenges during pregnancy leading to a range of maternal complications such as miscarriage, gestational hypertension, preeclampsia, preterm delivery, cesarean section deliveries and birth trauma. In addition to maternal complications, GDM and thyroid dysfunction are linked to various perinatal and neonatal morbidities including macrosomia, increased birth weight, shoulder dystocia, respiratory distress syndrome, neonatal hypoglycemia, hyperbilirubinemia, low birth weight, congenital hypothyroidism, hypocalcemia, impaired neurodevelopment in the child, etc. Placental human chorionic gonadotropin, sharing structural similarities with TSH transiently suppresses TSH secretion in the first trimester. Simultaneously, serum concentrations of FT4 and FT3 rise regulating key metabolic processes such as glucose, protein and lipid metabolism Yanachkova V et al study observed that higher TSH and FT3 concentration, lower FT4 concentrations and higher FT3:FT4 ratios may indicate an increased risk of developing GDM. Further research was needed to validate these results and explore the relationship between thyroid dysfunction and gestational diabetes. Hindi E. Stohl et al study conducted at John Hopkins showed a higher incidence of GDM in women with hypothyroidism compared to those with hyperthyroidism. Women with hypothyroidism had significantly higher rates of cesarean delivery. Huang K et al study showed a significant association between higher TSH levels in early pregnancy and an elevated risk of gestational diabetes, particularly in women with a pre pregnancy BMI more than or equal to 24kg/m2. Stressing the importance of early thyroid function evaluation, the findings propose potential preventive measures for GDM, especially in those with her BMI.

In proposed study, pregnant women visiting OPD/ANC at Kasturba Hospital fitting into inclusion criteria will be recruited.  TSH will be sent as a part of routine antenatal investigation. If TSH value is found to be abnormal, patient will be referred to Department of Endocrinology for evaluation. As part of evaluation FT4, anti TPO levels will be sent. Patient will then be classified into one of the five following categories: 1) Euthyroid (TSH- normal) 2) Subclinical hypothyroid (TSHelevated, FT4-normal) 3) Overt Hypothyroid (TSH- elevated, FT4- decreased) 4) Hyperthyroidism (TSH- decreased, FT4 increased) 5) Anti TPO positive.  In subsequent ANC visit, screening for GDM will be done either by Glucose tolerance test or 75 grams glucose challenge test. According to  IADPSG( Fasting blood glucose 92 mg/dl 1 hour post glucose value 180 mg/dl 2 hour post glucose value 153 mg/dl )Patient will be labelled as GDM if any one of the above mentioned values in deranged OR based on DIPSI guidelines (Blood sugar value > 140mg/dl).  Patient will then be grouped into either  Thyroid dysfunction in pregnancy with GDM or Thyroid dysfunction in pregnancy without GDM. Patient will be followed up till delivery. Perinatal and maternal outcomes will be studied. Collected data will be analyzed