Table 3.
The association of free and total T3 concentrations with birth weight
| Small for gestational age | Large for gestational age | Birth weight (g) | |||||
|---|---|---|---|---|---|---|---|
| n | OR (95% CI) | P value | OR (95% CI) | P value | Mean difference (95% CI) | P value | |
| Z-scores (full range) | |||||||
| FT3 | 26 269 | 1.02 (0.97 to 1.06) | .34 | 1.00 (0.96 to 1.05) | .75 | 2.38 (−2.8 to 7.6) | .37 |
| TT3 | 15 848 | 0.97 (0.91 to 1.01) | .22 | 1.03 (0.98 to 1.09) | .19 | 12.8 (6.5 to 19.1) | <.0001 |
| Z-scores (normal range) | |||||||
| FT3 | 25 059 | 1.00 (0.95 to 1.06) | .78 | 0.99 (0.94 to 1.05) | .88 | 3.87 (−2.4 to 10.1) | .22 |
| TT3 | 15 091 | 0.94 (0.88 to 1.00) | .068 | 1.02 (0.96 to 1.09) | .48 | 15.0 (7.4 to 22.5) | .0001 |
Table shows the association of maternal FT3 and TT3 (Z-scores) in full or within the normal range (2.5th-97.5th percentiles) with small for gestational age (SGA), large for gestational age (LGA) and continuous birth weight (grams). All analyses were adjusted for maternal age, BMI, ethnicity, smoking, parity, gestational age at blood sampling and fetal sex and gestational age at birth (for birth weight only).