Prepregnancy Hypothyroidism versus Gestational Hypothyroidism: A Comparative Study

Hypothyroidism managed inadequately in pregnancy may have grave outcomes for both mother and baby. Understanding pregnancy outcomes in our country with low awareness about thyroid diseases is important.

The objectives of the study were to evaluate demographic features and biochemical parameters in patients with prepregnancy hypothyroidism versus patients diagnosed to have primary hypothyroidism during pregnancy and to assess pregnancy outcomes.

Prospective design.

The study was conducted in a tertiary care center in Bengaluru for 2 years. The patients were divided into two groups - Group I: Prepregnancy hypothyroidism and Group II: Hypothyroid during pregnancy. They were further staged according to ESI guidelines as subclinical or overt hypothyroidism.

Chi-square and Mann-Whitney test.

A total of 452 pregnant women with hypothyroidism were analyzed. The data of 371 delivered pregnancies were available. Group I and II had 196 (43.36%) and 256 (56.64%) patients, respectively. Age at presentation (years) was 27.09 ± 4.19 in Group I versus 25.74 ± 4.29 in Group II (P = 0.003); gestational age (weeks) was 9.04 ± 5.41 in Group I versus 13.81 ± 9.12 in Group II (P = 0.000). There was one case of congenital hypothyroidism in baby in each group. Mean birth weight was 2.90 ± 0.39 kg in Group I versus 2.88 ± 0.36 kg in Group II; P = 0.608. There were four abortions in Group I versus ten in Group II (P = 0.231), 104 cesarean sections in Group I compared to 133 in Group II; (P = 0.382). There was no difference in number of cesarean sections, abortions and low birth weight babies between overt and subclinical hypothyroidism subgroups.

Group I patients presented earlier for testing suggesting awareness was good in this group. There was no difference in pregnancy outcome between the two groups. Overt versus subclinical status did not have any different effects on pregnancy outcomes in any group.