Hypothyroidism Complicating Pregnancy: A Local Perspective

Objective: To examine the thyroid status and adequacy of thyroxine replacement at the first antenatal visit in Hong Kong women with a known history of hypothyroidism prior to pregnancy. Methods: Data were obtained from an electronic database, which registered all medical diseases complicating pregnancy among women attending the high-risk obstetric clinic in a teaching hospital between 1 April 2006 and 31 December 2009. Results: A total of 136 eligible subjects were identified from 24,424 maternities during the study period. Thyroiditis was the most common cause of hypothyroidism followed by post-radioactive iodine treatment for previous hyperthyroidism. Overall, 96 (70.6%) women were hypothyroid according to the gestational age–specific reference ranges, and 29 (21.3%) were diagnosed with overt hypothyroidism. Furthermore, 63.5% of the women needed a mean dose increment of 44.6 ± 45.1% during pregnancy. Conclusion: The majority of women with hypothyroidism complicating pregnancy did not receive adequate hormone replacement early in the course of their pregnancy in Hong Kong. Hong Kong J Gynaecol Obstet Midwifery 2014; 14(1):38-42