Table 1.
Maternal and infant characteristics
| 400 m European n= 44 | 3600 m European n= 37 | 400 m Andean n= 44 | 3600 m Andean n= 43 | P-values | |
|---|---|---|---|---|---|
| Maternal characteristics | |||||
| Gestational age at ultrasound (weeks) | 37.7 ± 03 | 37.8 ± 0.2 | 38.3 ± 0.2 | 38.0 ± 0.2 | NS |
| Age (years) | 27 ± 1 | 30 ± 1 | 29 ± 1 | 33 ± 1 | P < 0.0001 altitude |
| P < 0.01 ancestry | |||||
| Parity (#) | 1.0 ± 0.2 | 1.0 ± 0.2 | 1.7 ± 0.2 | 1.5 ± 0.2 | P < 0.01 ancestry |
| Height (cm) | 161 ± 1 | 162 ± 1 | 156 ± 1 | 152 ± 1 | P < 0.0001 ancestry |
| Non-pregnant weight (kg) | 62 ± 2 | 61 ± 1 | 59 ± 2 | 58 ± 2 | NS |
| Non-pregnant Body Mass Index (kg m−2) | 24 ± 1 | 24 ± 1 | 24 ± 1 | 25 ± 1 | NS |
| Weight gain with pregnancy (kg) | 11 ± 1 | 13 ± 2 | 12 ± 1 | 14 ± 1 | P < 0.05 altitude |
| Infant characteristics | |||||
| Birth weight (grams (unadjusted values) | 3420 ± 65 | 2993 ± 56 | 3526 ± 44 | 3316 ± 59 | P < 0.0001 altitude |
| P < 0.0001 ancestry | |||||
| P= 0.10 interaction | |||||
| Birth weight (grams, adjusted values) | 3414 ± 33 | 2978 ± 37 | 3567 ± 24 | 3367 ± 36 | P < 0.0001 altitude |
| P < 0.0001 ancestry | |||||
| P < 0.005 interaction | |||||
| Fetal heart rate (BPM) | 140 ± 2 | 142 ± 1 | 143 ± 1 | 142 ± 2 | NS |
| Placental weight (g) | 477 ± 16 | 478 ± 20 | 463 ± 14 | 497 ± 17 | NS |
| Birth/placental weight ratio | 7.4 ± 0.2 | 6.5 ± 0.2 | 7.8 ± 0.2 | 6.9 ± 0.2 | P < 0.0001 altitude |
| P= 0.06 ancestry | |||||
| Ponderal index | 2.69 ± 0.03 | 2.64 ± 0.04 | 2.68 ± 0.04 | 2.70 ± 0.05 | P= 0.08 ancestry |
| Birth length (cm) | 50.1 ± 0.1 | 48.3 ± 0.1 | 50.9 ± 0.2 | 48.8 ± 0.1 | P < 0.0001 altitude |
| P < 0.0001 ancestry | |||||
| Abdominal circumference (cm) | 34.0 ± 0.1 | 32.9 ± 0.1 | 34.5 ± 0.1 | 34.6 ± 0.1 | P < 0.0001 ancestry |
| P < 0.001 interaction | |||||
| Head circumference (cm) | 34.7 ± 0.1 | 34.2 ± 0.1 | 34.9 ± 0.1 | 34.6 ± 0.1 | P < 0.01 altitude |
| P < 0.001 ancestry | |||||
| Clinically assessed gestational age at birth (weeks) | 38.5 ± 0.2 | 38.2 ± 0.2 | 38.8 ± 0.1 | 38.6 ± 0.2 | P= 0.08 ancestry |
| Days (from LMP) | 271 ± 1 | 270 ± 1 | 273 ± 1 | 272 ± 1 | P= 0.09 ancestry |
| Sex ratio M/F | 22/22 | 26/11 | 21/23 | 22/21 | NS |
Birth weights (BW) were adjusted for maternal age (MA) and parity (P) and for the infant's gestational age (GA, days from LMP) and sex (S, 0 male, 1 female), as follows: 400 m European BW =–4366 – 0.7(MA) + 89.3(P) + 29.5(GA) – 97(S); 3600 m European BW =–3559 + 8.3(MA) – 23.2(P) + 24.1(GA) – 251(S); 400 m Andean BW =–1552 – 0.9(MA) + 1.7(P) + 18.9(GA) – 51.0(S); 3600 m Andean BW =–2817 – 0.1(MA) + 90.1(P) + 22.3(GA) – 10 (S)).