Table 1.

Thyroid function reference values for fT3, fT4, TSH and fT3/fT4 ratio across pregnancy.

Pregnancy	fT3 pmol/l		fT4 pmol/l		TSH mIU/l		fT3/fT4
Week	Mean	S.D.	Mean	S.D.	Mean	S.D.	Mean
6	4.55	0.35	14.45	0.35	1.57	0.63	0.31
7	5.06	0.68	15.30	2.63	2.22	1.45	0.33
8	5.08	0.64	16.03	2.99	1.33	0.97	0.32
9	5.04	0.57	15.35	3.32	1.48	2.33	0.33
10	5.03	0.75	15.75	2.67	0.96	0.76	0.32
11	4.89	0.59	14.89	2.79	1.21	1.12	0.33
12	4.89	0.56	14.84	2.26	1.41	1.75	0.33
13	4.78	0.64	14.72	2.58	1.65	1.96	0.32
14	4.75	0.56	14.02	1.88	1.52	1.23	0.34
15	4.69	0.45	14.02	2.04	1.57	1.01	0.33
16	4.66	0.54	14.02	1.89	1.67	1.58	0.33
17	4.54	0.44	14.03	2.19	1.61	0.89	0.32
18	4.55	0.45	13.23	1.66	1.91	2.28	0.34
19	4.61	0.50	13.86	2.19	1.90	1.06	0.33
20	4.39	0.40	13.19	1.83	1.83	1.26	0.33
21	4.52	0.46	13.83	1.91	1.63	0.94	0.33
22	4.38	0.48	13.69	2.16	1.70	0.98	0.32
23	4.31	0.45	13.43	1.96	1.70	0.86	0.32
24	4.33	0.45	13.39	1.62	1.41	0.79	0.32
25	4.31	0.48	13.17	2.07	1.77	1.32	0.33
26	4.21	0.54	13.29	2.32	2.77	10.97	0.32
27	4.30	0.43	13.07	2.47	1.49	0.92	0.33
28	4.25	0.40	13.33	1.80	1.44	0.98	0.32
29	4.28	0.42	13.33	1.93	1.72	1.56	0.32
30	4.26	0.41	13.90	1.78	1.32	0.65	0.31
31	4.34	0.48	12.97	2.04	1.44	0.92	0.33
32	4.35	0.46	13.32	1.93	1.60	0.95	0.33
33	4.23	0.41	13.63	2.25	1.55	1.16	0.31
34	4.27	0.55	13.14	1.86	2.10	5.36	0.32
35	4.23	0.44	13.24	1.86	1.58	0.82	0.32
36	4.24	0.40	13.46	1.87	1.57	1.03	0.31
37	4.25	0.43	13.12	2.32	1.56	0.96	0.32
38	4.29	0.39	12.82	1.43	1.68	0.93	0.33
39	4.18	0.42	13.60	1.78	1.89	1.03	0.31
40	4.04	0.32	12.56	2.70	1.74	1.04	0.32
41	3.97	0.49	13.23	0.76	2.29	0.58	0.30
Total mean	4.47	0.48	13.81	2.06	1.66	1.53	0.32