Table 1.
Biochemical characteristics of the study population. Mean values ± standard deviation of age and gestational age, vitamin D metabolites and biochemical, hematological, and endocrinological serum parameters in 1st, 2nd, and 3rd pregnancy trimesters.
| Variable, units | 1st trimester of pregnancy, mean ± SD | 2nd trimester of pregnancy, mean ± SD | 3rd trimester of pregnancy, mean ± SD | Changes throughout pregnancy |
|---|---|---|---|---|
| T25OHD, ng/mL | 18.80 ± 9.96 | 20.26 ± 11.09 | 20.55 ± 11.56 | ↔ |
| F25OHD, pg/mL | 2.84 ± 1.54 | 2.41 ± 1.41 | 2.31 ± 1.48*** | ↓ |
| B25OHD, ng/mL | 1.05 ± 0.57 | 0.76 ± 0.47*** | 0.69 ± 0.44*** | ↓ |
| T1,25(OH)2D, pg/mL | 105.80 ± 42.59 | 150.95 ± 47.28*** | 163.28 ± 43.68*** | ↑ |
| F1,25(OH)2D, pg/mL | 0.27 ± 0.10 | 0.30 ± 0.10** | 0.31 ± 0.10*** | ↑ |
| B1,25(OH)2D, pg/mL | 9.05 ± 3.47 | 8.84 ± 2.93 | 8.58 ± 2.68 | ↔ |
| Age, years | 30.63 ± 6.36 | 29.54 ± 5.28 | 29.87 ± 5.86 | ↔ |
| Gestational age, weeks | 7.98 ± 1.84 | 21.29 ± 4.06*** | 33.25 ± 2.19§§§, *** | ↑ |
| PTH, pg/mL | 15.37 ± 10.76 | 14.60 ± 13.48 | 17.93 ± 13.98 | ↔ |
| BSAP, µg/mL | 12.93 ± 5.12 | 13.97 ± 5.86 | 18.01 ± 8.21§§§,*** | ↑ |
| Calcium, mmol/L | 2.38 ± 0.12 | 2.25 ± 0.13*** | 2.24 ± 0.10*** | ↓ |
| Phosphate, U/L | 4.39 ± 1.65 | 4.07 ± 1.24 | 4.33 ± 2.23 | ↔ |
| DBP, mg/L | 532.56 ± 138.73 | 690.00 ± 171.15*** | 762.70 ± 254.08*** | ↑ |
| LDL, mg/dL | 118.04 ± 34.00 | 158.52 ± 39.12*** | 184.16 ± 40.60§§,*** | ↑ |
| HDL, mg/dL | 59.36 ± 13.25 | 65.10 ± 12.40** | 67.48 ± 12.64*** | ↑ |
| LDL/HDL ratio | 2.05 ± 0.61 | 2.49 ± 0.63*** | 2.83 ± 0.82*** | ↑ |
| Adiponectin, µg/mL | 9.28 ± 4.15 | 8.06 ± 3.73* | 8.41 ± 3.97 | ↓ |
| Free T3, pg/mL | 3.10 ± 0.38 | 3.15 ± 0.38 | 3.03 ± 0.38§ | ↓ |
| Free T4, ng/dL | 1.02 ± 0.14 | 0.87 ± 0.12*** | 0.85 ± 0.11*** | ↓ |
| TSH, uU/mL | 1.48 ± 0.97 | 1.54 ± 0.79 | 1.45 ± 0.66 | ↔ |
| Hemoglobin, g/dL | 12.55 ± 0.94 | 11.53 ± 0.83*** | 11.66 ± 0.93*** | ↓ |
| RBC count, 106/µL | 4.34 ± 0.39 | 3.90 ± 0.35*** | 4.00 ± 0.34*** | ↓ |
| WBC count, 103/µL | 8.54 ± 2.14 | 9.55 ± 2.83* | 9.75 ± 2.33*** | ↑ |
| Platelet count, 103/µL | 232.55 ± 50.51 | 214.12 ± 42.94 | 220.68 ± 54.10 | ↔ |
| MCV, fL | 89.13 ± 5.42 | 89.77 ± 5.67 | 89.34 ± 5.39 | ↔ |
| MCH, pg | 29.18 ± 1.96 | 29.73 ± 2.12 | 29.32 ± 1.95 | ↔ |
| MCHC, g/dL | 32.75 ± 0.97 | 33.15 ± 0.96* | 32.93 ± 1.11 | ↔ |
| RDW, % | 13.97 ± 1.23 | 13.99 ± 1.11 | 13.87 ± 1.16 | ↔ |
| Hematocrit, % | 38.57 ± 2.85 | 34.86 ± 2.39*** | 35.51 ± 2.96*** | ↓ |
| Urea, mg/dL | 23.07 ± 5.85 | 17.97 ± 4.89*** | 17.93 ± 4.58*** | ↓ |
| Albumin, g/dL | 4.09 ± 0.38 | 3.45 ± 0.30*** | 3.30 ± 0.24*** | ↓ |
| Vitamin B6, ng/mL | 14.43 ± 18.70 | 7.34 ± 7.78*** | 5.55 ± 13.11§,*** | ↓ |
| Vitamin B12, pg/mL | 368.63 ± 157.81 | 279.23 ± 123.68*** | 275.75 ± 121.83*** | ↓ |
| Sodium, mmol/L | 137.80 ± 4.46 | 138.03 ± 2.80 | 137.77 ± 3.43 | ↔ |
| Zinc, µmol/L | 12.50 ± 2.83 | 10.13 ± 2.21** | 9.86 ± 2.13*** | ↓ |
B25OHD, bioavailable 25OHD; B1,25(OH)2D, bioavaialble 1,25(OH)2D; BSAP, bone-specific alkaline phosphatase; F25OHD, free 25OHD; F1,25(OH)2D, free 1,25(OH)2D; fT3, free triiodothyronine; fT4, free thyroxine; HDL, high-density lipoprotein cholesterol; LDL, low-density lipoprotein cholesterol; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; MCV, mean corpuscular volume of red blood cells; PTH, parathyroid hormone; RBC, red blood cell; RDW, red blood cell distribution width; T25OHD, total 25OHD; T1,25(OH)2D, total 1,25(OH)2D; WBC, white blood cell. *p < 0.05 versus 1st trimester; **p < 0.01 versus 1st trimester; ***p < 0.001 versus 1st trimester; §§p < 0.01 versus 2nd trimester; §§§p < 0.001 versus 2nd trimester.