Table 1
Maternal and neonatal clinical characteristics of the study sample (N = 408).
| CHARACTERISTIC | CONTROLS (AGA), N = 272 | CASES (SGA), N = 136 | TOTAL, N = 408 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| MEAN (SD) | MIN | MAX | MEAN (SD) | MIN | MAX | MEAN (SD) | MIN | MAX | |
| Birth weight (g) | 2806 (319) | 1446 | 3600 | 2257 (329) | 700 | 2760 | 2623 (413) | 700 | 3600 |
| Gestational age (weeks) | 38 (2) | 31 | 41 | 39 (2) | 30 | 41 | 38 (2) | 30 | 41 |
| Maternal age (years) | 28 (6) | 16 | 41 | 27 (5) | 17 | 44 | 28 (6) | 16 | 44 |
| Prepregnancy weight (kg)* | 52.7 (10.5) | 34.0 | 85.0 | 49.1 (11.5) | 30.5 | 83.6 | 51.6 (10.9) | 30.5 | 85.0 |
| Maternal height (cm)** | 155 (6) | 142 | 172 | 152 (6) | 139 | 180 | 154 (6) | 139 | 180 |
| Prepregnancy BMI (kg/m2) | 21.9 (4.2) | 13.6 | 37.3 | 21.1 (4.8) | 12.7 | 37.2 | 21.7 (4.4) | 12.7 | 37.3 |
| Gestational weight gain (kg) | 9.7 (4.1) | 1.0 | 23.6 | 9.5 (4.5) | 1.7 | 22.0 | 9.7 (4.2) | 1.0 | 23.6 |
[i] Abbreviations: AGA, average‑for‑gestational‑age; BMI, body mass index; SD, standard deviation; SGA, small‑for‑gestational‑age. *48 records (11.8%) missing prepregnancy weight. **12 records (2.9%) missing height data.
Table 2
Unadjusted univariate analysis of maternal and antenatal factors associated with SGA (N = 408).
| VARIABLE | TOTAL (N = 408) N (%) | SGA CASES (N = 136) N (%) | AGA CONTROLS (N = 272) N (%) | P VALUE |
|---|---|---|---|---|
| Maternal anthropometric factors | ||||
| Prepregnancy weight (kg) | <0.001a | |||
| <50 kg | 165 (45.8) | 68 (59.1) | 97 (39.6) | |
| >= 50 kg (reference) | 195 (54.2) | 47 (40.9) | 148 (60.4) | |
| Maternal height (cm) | 0.007a | |||
| <= 150 cm | 118 (29.2) | 52 (38.8) | 66 (24.4) | |
| 151–160 cm | 229 (56.7) | 69 (51.5) | 160 (59.3) | |
| >160 cm | 57 (14.1) | 13 (9.7) | 44 (16.3) | |
| Prepregnancy BMI (kg/m2) | 0.003a | |||
| <18.5 (underweight) | 93 (26.0) | 41 (36.0) | 52 (21.3) | |
| 18.5–24.9 (normal; reference) | 185 (51.7) | 45 (39.5) | 140 (57.4) | |
| >= 25 (overweight/obese) | 80 (22.3) | 28 (24.6) | 52 (21.3) | |
| Obstetric history | ||||
| Parity (primiparous) | 170 (40.9) | 63 (46.3) | 107 (39.3) | 0.177 |
| History of subfertility | 13 (3.1) | 7 (5.1) | 6 (2.2) | 0.136 |
| Previous LBW infant | 74 (17.8) | 40 (29.4) | 34 (12.5) | <0.001a |
| Previous miscarriage | 64 (15.4) | 21 (15.4) | 43 (15.8) | 0.923 |
| Previous cesarean section | 52 (12.5) | 14 (10.3) | 38 (14.0) | 0.294 |
| Consanguinity | 13 (3.1) | 7 (5.1) | 6 (2.2) | 0.136 |
| Antenatal and delivery factors | ||||
| Anemia in pregnancy | 111 (26.7) | 45 (33.8) | 66 (25.1) | 0.067 |
| Folic acid supplementation (yes) | 274 (65.9) | 83 (61.0) | 191 (70.2) | 0.062 |
| Gestational weight gain | 0.471 | |||
| Below recommended | 170 (47.8) | 58 (51.3) | 112 (46.1) | |
| Within recommended | 133 (37.4) | 37 (32.7) | 96 (39.5) | |
| Above recommended | 53 (14.9) | 18 (15.9) | 35 (14.4) | |
| Antepartum hemorrhage | 9 (2.2) | 4 (2.9) | 5 (1.8) | 0.489b |
| Gestational hypertension | 11 (2.6) | 4 (3.0) | 7 (2.6) | 1.000b |
| Mode of delivery (cesarean section) | 137 (33.6) | 57 (41.9) | 80 (29.4) | 0.012a |
[i] Abbreviations: AGA, average‑for‑gestational‑age; LBW, low birth weight; LSCS, lower segment cesarean section; SGA, small‑for‑gestational‑age. aP < 0.05 (statistically significant). bFisher exact test applied.
Table 3
Multivariable binary logistic regression: adjusted odds ratios for maternal risk factors of SGA (N = 408).
| MODEL | VARIABLE | ADJUSTED OR | 95% CI LOWER | 95% CI UPPER | P VALUE |
|---|---|---|---|---|---|
| Model 1 | Prepregnancy weight <50 kg (ref: >= 50 kg) | 2.18 | 1.28 | 3.69 | 0.004a |
| Height < = 150 cm (ref: 151‑160 cm) | 1.98 | 1.14 | 3.45 | 0.015a | |
| Height > 160 cm (ref: 151–160 cm) | 0.82 | 0.37 | 1.82 | 0.615 | |
| Previous LBW infant | 3.87 | 1.98 | 7.57 | <0.001a | |
| Consanguinity | 1.95 | 0.69 | 5.58 | 0.210 | |
| Folic acid supplementation | 1.44 | 0.84 | 2.49 | 0.186 | |
| Anemia in pregnancy | 1.37 | 0.77 | 2.41 | 0.285 | |
| Model 2 | BMI < 18.5 kg/m2 (ref: 18.5–24.9 kg/m2) | 2.24 | 1.27 | 3.94 | 0.005a |
| BMI >= 25 kg/m2 (ref: 18.5–24.9 kg/m2) | 1.95 | 1.04 | 3.64 | 0.036a | |
| Previous LBW infant | 3.87 | 2.01 | 7.47 | <0.001a | |
| Consanguinity | 1.61 | 0.59 | 4.44 | 0.354 | |
| Folic acid supplementation | 1.33 | 0.78 | 2.28 | 0.295 | |
| Anemia in pregnancy | 1.32 | 0.76 | 2.32 | 0.325 |
[i] Abbreviations: BMI, body mass index; CI, confidence interval; LBW, low birth weight; OR, odds ratio; SGA, small‑for‑gestational‑age. Both models adjusted a priori for infant sex, maternal age, parity, and educational level. Reference categories: weight >= 50 kg; height 151–160 cm; BMI 18.5–24.9 kg/m2. aStatistically significant (P < 0.05).