| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[33] Hypothyroidism in pregnancy: Vadiveloo T, Mires GJ, Donnan PT, Leese GP. Thyroid testing in pregnant women with thyroid dysfunction in Tayside, Scotland: the thyroid epidemiology, audit and research study (TEARS). ClinEndocrinol (Oxf) 2013; 78:466.http://www.ncbi.nlm.nih.gov/pubmed/22548296
Hypothyroidism in pregnancy: Yassa L, Marqusee E, Fawcett R, Alexander EK. Thyroid hormone early adjustment in pregnancy (the THERAPY) trial. J ClinEndocrinolMetab 2010; 95:3234. http://www.ncbi.nlm.nih.gov/pubmed/20463094
Hypothyroidism in pregnancy: Alexander EK, Marqusee E, Lawrence J, Jarolim P, Fischer GA, Larsen PR. Timing and magnitude of increases in levothyroxine requirements during pregnancy in women with hypothyroidism. N Engl J Med. 2004 Jul 15;351(3):241-9.http://www.ncbi.nlm.nih.gov/pubmed/15254282
Hypothyroidism in pregnancy: Abalovich M, Gutierrez S, Alcaraz G, Maccallini G, Garcia A, Levalle O. Overt and subclinical hypothyroidism complicating pregnancy. Thyroid. 2002 Jan;12(1):63-8. http://www.ncbi.nlm.nih.gov/pubmed/11838732