Maternal characteristics and neonatal outcomes in PPG (1978–1993) and CSL (2002–2008) cohorts
| Maternal characteristics | PPG | CSL | P values |
| n=333 | n=358 | ||
| Maternal age at delivery (years) | 26.4±5.1 | 27.5±6.0 | 0.008 |
| Married, yes* | 224 (67.3) | 217 (60.6) | 0.01 |
| Race | <0.001 | ||
| White | 282 (84.7) | 225 (62.8) | |
| Black | 47 (14.1) | 69 (19.3) | |
| Other | 4 (1.2) | 64 (17.9) | |
| Nulliparous, yes | 166 (49.9) | 183 (51.1) | 0.74 |
| Prepregnancy BMI (kg/m2) | 23.0±3.4 | 26.9±6.3 | <0.001 |
| Prepregnancy BMI category | <0.001 | ||
| Underweight (BMI <18.5 kg/m2) | 11 (3.3) | 6 (1.7) | |
| Normal (18.5 kg/m2≤BMI<25.0 kg/m2) | 253 (76.0) | 168 (46.9) | |
| Overweight (25.0 kg/m2≤BMI<30.0 kg/m2) | 56 (16.8) | 97 (27.1) | |
| Obese (BMI ≥30.0 kg/m2) | 13 (3.9) | 87 (24.3) | |
| Prepregnancy overweight/obese | 69 (20.7) | 184 (51.4) | <0.001 |
| Gestational weight gain (kg) | 14.4±5.6 | 14.5±7.4 | 0.77 |
| IOM guidelines | |||
| Under | 74 (22.2) | 62 (17.3) | <0.001 |
| Within | 118 (35.5) | 95 (26.5) | |
| Over | 141 (42.3) | 201 (56.2) | |
| Pre-eclampsia, yes | 50 (15.0) | 55 (15.4) | 0.90 |
| Previous caesarean section, yes* | 105 (31.6) | 86 (24.0) | 0.08 |
| Caesarean section, yes | 233 (70.0) | 239 (66.8) | 0.36 |
| Preterm delivery, yes | |||
| Delivery prior to 34 weeks | 33 (9.9) | 48 (13.4) | 0.15 |
| Delivery prior to 37 weeks | 114 (34.2) | 152 (42.6) | 0.03 |
| Neonatal outcomes† | |||
| Male | 186 (56.2) | 193 (53.9) | 0.60 |
| Respiratory distress during labour | 37 (11.1) | 45 (12.8) | 0.49 |
| Gestational age (weeks) | 37.0±2.4 | 36.1±2.7 | <0.001 |
| Apgar less than 7 (@5 min) | 59 (17.7) | 23 (6.4) |
Mean±SD are shown for all continuous variables and n (%) are shown for categorical variables.
*PPG: marital status missing for 11 women; CSL, previous caesarean section missing for 20 women.
†Neonatal outcomes exclude stillbirths and neonatal deaths.
BMI, body mass index; CSL, Consortium on Safe Labor; IOM, Institute of Medicine; PPG, Pregnancy Program Project.