Table 1 General characteristics of the study participants according to maternal age
Characteristics | Total (n = 19,854) | Maternal age | P-value | |
|---|---|---|---|---|
31–34 yr (n = 12,189) | ≥ 35 yr (n = 7665) | |||
Mothers | Â | Â | Â | Â |
Pre-pregnancy BMI (kg/cm2)a | 21.3 (19.7, 23.2) | 21.1 (19.5, 22.9) | 21.7 (20.1, 23.5) | < 0.0001 |
Underweight (n (%)) | 1965 (9.9) | 1422 (11.7) | 543 (7.1) | < 0.0001 |
Normal weight (n (%)) | 12,477 (62.8) | 7812 (64.1) | 4665 (60.9) | Â |
Overweight/obese (n (%)) | 5412 (27.3) | 2955 (24.2) | 2457 (32.1) | Â |
Gestational weight gain (kg) | 12.5 (10.0, 15.0) | 13.0 (10.0, 15.0) | 12.0 (9.5, 15.0) | < 0.0001 |
Rate of second and third trimester weight gain (kg/wk) | 0.46 (0.36, 0.55) | 0.47 (0.38, 0.56) | 0.44 (0.34, 0.54) | < 0.0001 |
Gestational diabetes mellitus (n (%)) | 5193 (26.2) | 2800 (23.0) | 2393 (31.2) | < 0.0001 |
Preeclampsia (n (%)) | 349 (1.8) | 180 (1.5) | 169 (2.2) | < 0.0001 |
Caesarean delivery (n (%)) | 13,723 (69.1) | 7754 (63.6) | 5969 (77.9) | < 0.0001 |
Newborns | Â | Â | Â | Â |
Gestational age at delivery (weeks) | 39.1 (38.7, 39.7) | 39.3 (38.7, 39.9) | 39.0 (38.5, 39.4) | < 0.0001 |
Gender, females (n (%)) | 9640 (48.6) | 5889 (48.3) | 3751 (48.9) | 0.39 |
Birth length (cm) | 50.0 (49.0, 51.0) | 50.0 (49.0, 51.0) | 50.0 (48.0, 51.0) | 0.0002 |
Birth weight (g) | 3300 (3035, 3570) | 3300 (3040, 3570) | 3300 (3030, 3570) | 0.38 |
Preterm birth (n (%)) | 881 (4.4) | 490 (4.0) | 391 (5.1) | 0.0003 |
Macrosomia (n (%)) | 926 (4.7) | 575 (4.7) | 351 (4.6) | 0.65 |
Large for gestational age (n (%)) | 1592 (8.0) | 936 (7.7) | 656 (8.6) | 0.03 |
Small for gestational age (n (%)) | 1133 (5.7) | 725 (6.0) | 408 (5.3) | 0.06 |