TABLE 2.
Associations of early pregnancy serum ferritin with systolic blood pressure and diastolic blood pressure during pregnancy (n = 5979)1
| Early pregnancy | Mid pregnancy | Late pregnancy | ||||
|---|---|---|---|---|---|---|
| Early pregnancy serum ferritin | β (95% CI) | n | β (95% CI) | n | β (95% CI) | n |
| Differences in systolic blood pressure (mmHg) | ||||||
| Quintile 12, 2–26 μg/L | –0.07 (–0.99 to 0.85) | 1189 | –0.09 (-1.02 to 0.83) | 1121 | –0.64 (–1.59 to 0.31) | 1110 |
| Quintile 22, 26–42 μg/L | 0.33 (–0.57 to 1.24) | 1190 | –0.33 (–1.24 to 0.57) | 1141 | –0.75 (–1.67 to 0.17) | 1146 |
| Quintile 3, 42–63 μg/L | reference | 1187 | reference | 1132 | reference | 1127 |
| Quintile 42, 63–96 μg/L | 0.14 (–0.76 to 1.04) | 1190 | –0.36 (–1.26 to 0.54) | 1156 | –0.12 (–1.03 to 0.80) | 1144 |
| Quintile 52, 96–390 μg/L | 0.35 (–0.56 to 1.26) | 1184 | 0.64 (–0.26 to 1.55) | 1159 | –0.08 (–1.01 to 0.84) | 1150 |
| SDS3 | –0.01 (–0.31 to 0.30) | 5940 | 0.20 (–0.10 to 0.51) | 5709 | 0.18 (–0.13 to 0.49) | 5709 |
| Differences in diastolic blood pressure, mmHg | ||||||
| Quintile 12, 2–26 μg/L | –0.23 (–0.94 to 0.48) | 1189 | 0.16 (–0.56 to 0.89) | 1120 | –0.06 (–0.79 to 0.67) | 1110 |
| Quintile 22, 26–42 μg/L | –0.02 (–0.72 to 0.68) | 1190 | 0.07 (–0.64 to 0.78) | 1141 | 0.0 (–0.72 to 0.72) | 1146 |
| Quintile 3, 42–63 μg/L | reference | 1187 | reference | 1132 | reference | 1126 |
| Quintile 42, 63–96 μg/L | 0.53 (–0.16 to 1.23) | 1190 | 0.38 (–0.33 to 1.08) | 1155 | 0.56 (–0.15 to 1.28) | 1144 |
| Quintile 52, 96–390 μg/L | 0.68 (–0.03 to 1.38) | 1184 | 0.90 (0.18–1.61)4 | 1159 | 0.62 (–0.10 to 1.34) | 1150 |
| SDS3 | 0.27 (0.03–0.51)4 | 5940 | 0.23 (–0.01 to 0.47) | 5707 | 0.23 (–0.02 to 0.47) | 5676 |
Models are adjusted for maternal age, ethnicity, educational level, parity, prepregnancy BMI, folic acid supplementation, smoking, gestational age at time of blood sampling, gestational age at time of blood pressure measurements, and CRP levels. CRP, C-reactive protein; SDS, standard deviation score.
Values are regression coefficients (95% CIs) and reflect the difference in mmHg blood pressure per serum ferritin quintile. Groups are compared to women in quintile 3 (serum ferritin: 42 μg/L–63 μg/L) as a reference. Estimates are from multiple imputed data.
Values are regression coefficients (95% CI) and reflect the difference in mmHg blood pressure per log serum ferritin SDS.
4 P value < 0.05.