Table 3.
Weighted Multivariate Cross-Sectional Associations Between Thyroid Function Parameters and Birth Weight z Scores by Study Visit of Sample Collection (n = 439 Pregnant Women)
| Hormones | Visit 1 (Median 10 wk) | Visit 2 (Median 18 wk) | Visit 3 (Median 26 wk) | Visit 4 (Median 35 wk) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | β (95% CI) | P Value | n | β (95% CI) | P Value | n | β (95% CI) | P Value | n | β (95% CI) | P Value | |
| TSHa | 303 | −0.02 (−0.13 to 0.10) | 0.79 | 308 | 0.02 (−0.17 to 0.20) | 0.86 | 297 | −0.14 (−0.36 to 0.09) | 0.23 | 259 | −0.16 (−0.38 to 0.05) | 0.13 |
| FT4a | 359 | −0.41 (−0.64 to −0.18) | <0.001 | 357 | −0.26 (−0.46 to −0.05) | 0.01 | 339 | −0.24 (−0.44 to −0.05) | 0.02 | 330 | −0.10 (−0.27 to 0.07) | 0.25 |
| T4 | 349 | −0.01 (−0.06 to 0.05) | 0.79 | 346 | −0.06 (−0.12 to 0.00) | 0.06 | 324 | −0.08 (−0.13 to −0.02) | 0.01 | 323 | −0.05 (−0.11 to 0.00) | 0.06 |
| T3 | 290 | 0.25 (−0.09 to 0.59) | 0.15 | 292 | 0.25 (−0.09 to 0.59) | 0.16 | 277 | 0.35 (0.01 to 0.69) | 0.04 | 228 | 0.18 (−0.13 to 0.50) | 0.26 |
All models adjusted weighted by preterm birth case-control sampling probabilities and adjusted for gestational age at time of sample collection, maternal age, race/ethnicity, BMI at initial study visit, insurance provider, parity, and fetal sex.
a
ln-transformed prior to analysis.
b
Bold text indicates P < 0.05.