Table 1.
Maternal and birth characteristics in the second live birth pregnancy categorised by maternal weight change gain from the first live birth pregnancy for the period of January 2003 to September 2017, University Hospital Southampton NHS Foundation Trust, Hampshire, England
| Lost ≤ −1 kg/m2 from previous pregnancy | Weight stable (> −1 to <1 kg/m2) | Gained 1−3 kg/m2 from previous pregnancy | Gained ≥3 kg/m2 from previous pregnancy | P value* | |
|---|---|---|---|---|---|
| N | 2548 | 5785 | 4446 | 3161 | |
| Maternal age, years (mean±SD) | 28.7±5.4 | 29.8±5.3 | 29.2±5.4 | 27.3±5.5 | <0.001 |
| Timing of first booking appointment, weeks (mean±SD) | 10.8±2.3 | 11.0±2.3 | 11.1±2.4 | 11.0±2.6 | <0.001 |
| Maternal BMI at booking, kg/m2 (mean±SD) | 24.1±5.1 | 23.8±4.4 | 25.9±4.7 | 30.8±5.9 | <0.001 |
| Maternal BMI at booking in first pregnancy (%, 95% CI) | |||||
| Underweight (<18.5) | 0.8 (0.5 to 1.2) | 4.3 (3.8 to 4.8) | 5.3 (4.7 to 6.0) | 3.7 (3.1 to 4.4) | <0.001 |
| Normal weight (18.5 to 24.9) | 47.6 (45.6 to 49.5) | 67.4 (66.2 to 68.6) | 62.5 (61.0 to 63.9) | 49.0 (47.2 to 50.7) | |
| Overweight (25.0 to 29.9) | 30.1 (28.3 to 31.9) | 19.4 (18.4 to 20.5) | 22.0 (20.8 to 23.3) | 29.5 (28.0 to 31.2) | |
| Obese (≥30.0) | 21.5 (19.9 to 23.2) | 8.9 (8.2 to 9.7) | 10.2 (9.3 to 11.1) | 17.8 (16.5 to 19.2) | |
| Maternal BMI at booking in second pregnancy (%, 95% CI) | |||||
| Underweight (<18.5) | 6.9 (5.9 to 7.9) | 4.3 (3.8 to 4.8) | 0.6 (0.4 to 0.9) | 0.0 (0.0 to 0.2) | <0.001 |
| Normal weight (18.5 to 24.9) | 61.1 (59.2 to 63.0) | 66.8 (65.6 to 68.1) | 50.7 (49.2 to 52.1) | 14.9 (13.7 to 16.2) | |
| Overweight (25.0 to 29.9) | 20.1 (18.6 to 21.7) | 19.7 (18.7 to 20.7) | 32.6 (31.2 to 34.0) | 36.7 (35.0 to 38.4) | |
| Obese (≥30.0) | 11.9 (10.7 to 13.3) | 9.2 (8.5 to 10.0) | 16.1 (15.0 to 17.2) | 48.3 (46.6 to 50.1) | |
| Maternal smoking status at booking (%, 95% CI) | |||||
| Never smoked/quit | 57.2 (55.3 to 59.2) | 63.0 (61.8 to 64.3) | 60.5 (59.0 to 62.0) | 50.7 (48.9 to 52.4) | <0.001 |
| Stopped >1 year before conceiving | 16.1 (14.6 to 17.5) | 17.2 (16.3 to 18.2) | 17.7 (16.5 to 18.8) | 14.9 (13.7 to 16.2) | |
| Stopped <1 year prior to conceiving | 4.0 (3.3 to 4.8) | 2.8 (2.4 to 3.2) | 3.5 (3.0 to 4.1) | 4.9 (4.2 to 5.7) | |
| Stopped when pregnancy confirmed | 6.8 (5.8 to 7.8) | 5.9 (5.3 to 6.6) | 6.9 (6.2 to 7.7) | 10.3 (9.3 to 11.4) | |
| Continued smoking | 15.9 (14.5 to 17.4) | 11.0 (10.2 to 11.8) | 11.4 (10.5 to 12.4) | 19.1 (17.8 to 20.6) | |
| Maternal education (%, 95% CI) | |||||
| Secondary (GCSE) or under | 30.7 (28.9 to 32.5) | 24.0 (22.9 to 25.2) | 29.4 (28.1 to 30.8) | 36.3 (34.6 to 38.0) | <0.001 |
| College (A levels) | 40.4 (38.5 to 42.3) | 38.8 (37.6 to 40.1) | 39.5 (38.1 to 41.0) | 45.8 (44.0 to 47.5) | |
| University degree or above | 28.9 (27.2 to 30.7) | 37.1 (35.9 to 38.4) | 31.1 (29.7 to 32.5) | 17.9 (16.6 to 19.3) | |
| Maternal employment (%, 95% CI) | |||||
| Employed | 66.2 (64.3 to 68.0) | 71.7 (70.5 to 72.9) | 67.2 (65.8 to 68.5) | 56.5 (54.8 to 58.2) | <0.001 |
| Unemployed | 31.8 (30.0 to 33.7) | 26.9 (25.8 to 28.1) | 31.1 (29.7 to 32.5) | 41.6 (39.8 to 43.3) | |
| In education | 0.9 (0.6 to 1.4) | 0.8 (0.6 to 1.1) | 1.1 (0.8 to 1.4) | 1.3 (0.9 to 1.8) | |
| Not specified | 1.0 (0.7 to 1.5) | 0.6 (0.4 to 0.8) | 0.7 (0.5 to 1.0) | 0.6 (0.4 to 1.0) | |
| Ethnicity (%, 95% CI) | |||||
| White | 89.9 (88.7 to 91.1) | 88.0 (87.1 to 88.8) | 85.1 (84.0 to 86.1) | 84.8 (83.5 to 86.1) | <0.001 |
| Mixed | 0.8 (0.5 to 1.3) | 0.9 (0.7 to 1.2) | 1.4 (1.1 to 1.8) | 1.6 (1.1 to 2.0) | |
| Asian | 4.8 (4.0 to 5.7) | 5.6 (5.0 to 6.0) | 7.2 (6.5 to 8.0) | 7.7 (6.8 to 8.7) | |
| Black/African/Caribbean | 0.6 (0.4 to 1.0) | 1.0 (0.8 to 1.3) | 1.6 (1.3 to 2.1) | 2.4 (1.9 to 3.0) | |
| Other | 0.7 (0.4 to 1.1) | 1.0 (0.8 to 1.3) | 1.0 (0.8 to 1.4) | 1.3 (0.9 to 1.7) | |
| Not specified | 3.1 (2.5 to 3.9) | 3.5 (3.0 to 4.0) | 3.6 (3.1 to 4.2) | 2.2 (1.8 to 2.8) | |
| Interpregnancy interval (median, IQR) | 21.7 (14.4 to 32.7) | 21.6 (14.1 to 32.0) | 23.7 (14.4 to 35.6) | 27.7 (16.0 to 45.6) | <0.001 |
| Interpregnancy interval (%, 95% CI) | |||||
| 0–11 months | 17.4 (15.9 to 18.9) | 17.6 (16.6 to 18.6) | 18.1 (17.0 to 19.3) | 16.6 (15.4 to 17.9) | <0.001 |
| 12–23 months | 39.8 (37.8 to 41.7) | 39.9 (38.6 to 41.1) | 33.1 (31.7 to 34.5) | 26.3 (24.8 to 27.9) | |
| 24–35 months | 22.6 (21.0 to 24.2) | 23.6 (22.5 to 24.7) | 24.4 (23.2 to 25.7) | 20.5 (19.1 to 21.9) | |
| 36 months or more | 20.3 (18.7 to 21.9) | 18.9 (17.9 to 20.0) | 24.3 (23.1 to 25.6) | 36.5 (34.9 to 38.2) | |
| Birth weight, g (mean±SD) | 3463±563 | 3467±523 | 3507±536 | 3531±558 | |
| Previous size at birth (first pregnancy) | |||||
| Small-for-gestational age | 13.1 (11.8 to 14.4) | 12.6 (11.8 to 13.5) | 11.7 (10.8 to 12.7) | 12.4 (11.3 to 13.6) | 0.11 |
| Appropriate-for-gestational age | 79.6 (77.9 to 81.1) | 81.1 (80.0 to 82.1) | 81.2 (80.1 to 82.4) | 79.9 (78.4 to 81.3) | |
| Large-for-gestational age | 7.4 (6.4 to 8.5) | 6.3 (5.7 to 7.0) | 7.1 (6.3 to 7.8) | 7.7 (6.8 to 8.7) | |
| Size at birth (second pregnancy) | |||||
| Small-for-gestational age | 8.7 (7.6 to 9.8) | 7.0 (6.4 to 7.7) | 6.2 (5.5 to 6.9) | 6.7 (5.9 to 7.6) | <0.001 |
| Appropriate-for-gestational age | 79.0 (77.3 to 80.5) | 81.1 (80.0 to 82.1) | 80.3 (79.1 to 81.5) | 77.4 (75.9 to 78.9) | |
| Large-for-gestational age | 12.4 (11.1 to 13.7) | 11.9 (11.1 to 12.8) | 13.5 (12.5 to 14.5) | 15.9 (14.6 to 17.2) | |
*
P values calculated using ANOVA for continuous and χ2 test for categorical variables.