Table 1. Characteristics of Study Population Stratified According to Tertiles of Infant Birth Weight.
| Characteristic | Infant Birth Weight Tertile | ||
|---|---|---|---|
| Lowest (1800-3060 g) |
Middle (3100-3450 g) |
Highest (3500-6000 g) |
|
| Pregravid Assessment | |||
| Participants, No. | 343 | 434 | 387 |
| Weeks before pregnancy, median (IQR) | 15.4 (2.6 to 46.3) | 20.3 (5.6 to 53) | 22.4 (5.9 to 60.7) |
| Age, mean (SD), y | 25 (3) | 25 (3) | 26 (4) |
| Education, median (IQR), y | 10 (9 to 12) | 9 (9 to 12) | 12 (9 to 12) |
| Smoking, No. (%) | 0 | 1 (0.2) | 5 (1.3) |
| Weight, mean (SD), kg | 47.8 (5.8) | 49.8 (6.8) | 51.5 (7.1) |
| BMI, mean (SD) | 19.5 (2.1) | 20.1 (2.5) | 20.7 (2.8) |
| Waist, mean (SD), m | 69 (8) | 71 (7) | 72 (7) |
| BP, mean (SD), mm Hg | |||
| Systolic | 111 (12) | 112 (12) | 110 (13) |
| Diastolic | 71 (9) | 72 (9) | 71 (9) |
| Cholesterol, mean (SD), mg/dL | |||
| Total | 150.6 (50.2) | 150.6 (38.6) | 150.6 (46.3) |
| LDL | 81.1 (30.9) | 77.2 (27.0) | 81.1 (30.9) |
| HDL | 57.9 (19.3) | 61.8 (15.4) | 57.9 (19.3) |
| Triglycerides, median (IQR), mg/dL | 70.8 (53.1 to 106.2) | 79.6 (53.1 to 115.0) | 79.6 (61.9 to 115.0) |
| Blood glucose, mean (SD), mg/dL | 81.1 (21.6) | 79.3 (21.6) | 82.9 (19.8) |
| During Pregnancy | |||
| Weight gain during gestational intervals, median (IQR), kg | |||
| Pregravid to 14 wk | 1.0 (−1.0 to 4.0) | 0.6 (−1.0 to 3.0) | 1.5 (−0.5 to 4.0) |
| 14-18 wk | 1.5 (0.3 to 2.7) | 1.8 (0.8 to 3.0) | 2.0 (1.0 to 3.5) |
| 19-23 wk | 2.8 (2.0 to 4.0) | 3.0 (2.0 to 4.5) | 3.0 (2.0 to 4.5) |
| 24-28 wk | 3.0 (2.0 to 4.4) | 3.0 (2.0 to 4.0) | 3.0 (2.0 to 4.7) |
| 29-30 wk | 2.5 (1.5 to 4.0) | 2.5 (1.5 to 3.7) | 2.2 (1.2 to 3.5) |
| 31-32 wk | 1.5 (0.5 to 2.0) | 1.0 (0.3 to 2.0) | 1.0 (0.3 to 2.0) |
| 33-34 wk | 1.0 (0 to 2.0) | 1.0 (0.5 to 2.0) | 1.0 (0.5 to 2.0) |
| 35-36 wk | 1.0 (0.5 to 2.0) | 1.3 (0.5 to 2.5) | 1.0 (0.5 to 2.3) |
| 37-38 wk | 1.1 (0.5 to 2.0) | 1.0 (0 to 2.0) | 1.0 (0.5 to 2.0) |
| 39-40 wk | 0.8 (0.3 to 1.5) | 1.0 (0 to 1.5) | 1.0 (0.4 to 2.0) |
| At Delivery | |||
| Length of gestation, mean (SD), wk | 38.9 (1.6) | 39.1 (1.1) | 39.6 (3.0) |
| Preterm delivery, No. (%) | 32 (9.3) | 3 (0.7) | 3 (0.8) |
| Male infant, No. (%)a | 154 (45.2) | 228 (52.8) | 237 (61.4) |
| Gestational diabetes, No. (%) | 3 (0.9) | 6 (1.4) | 13 (3.4) |
| Pre-eclampsia, No. (%) | 16 (4.7) | 10 (2.3) | 4 (1.0) |
| Total maternal weight gain in pregnancy, median (IQR), kg | 14.5 (12.0-18.5) | 16.0 (13.0-19.5) | 17.5 (14.5 to 22.0) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); BP, blood pressure; HDL, high-density lipoprotein; IQR, interquartile range; LDL, low-density lipoprotein.
SI conversion factors: To convert total, LDL, and HDL cholesterol to millimoles per liter, multiply by 0.0259; glucose to millimoles per liter, multiply by 0.0555; and triglycerides to millimoles per liter, multiply by 0.0113.
a
Infant sex was missing for 1 woman in the highest tertile and for 2 women in each of the other 2 tertiles.