Table 4.
Descriptive variables in spontaneous, preterm, and term births.a
| Descriptive variable | SPTB | STB | P value (ANOVA) |
|---|---|---|---|
| Gestational age at enrollment (days) | 144.8±51, 143 (46–254) | 144.0±48.9, 142 (38–279) | 0.736 |
| Maternal age (years) | 24.6±6, 24 (16–43) | 24.3±5.9, 23 (16–42) | 0.307 |
| Maternal weight (kg) | 59.5±14, 56.6 (34–129.8) | 63.8±14.4, 60.7 (30.1–136) | <0.001 |
| Maternal length (cm) | 158±6, 158 (141–177) | 159±6, 159 (138–184) | 0.002 |
| Maternal head circumference (mm) | 542±19, 540 (485–602) | 545±19, 545 (215–696) | 0.002 |
| Maternal mid upper arm circumference (mm) | 262.5±43.4, 251.3 (185–535) | 273.4±44.1, 265 (175–480) | <0.001 |
| BMI (kg/m2) | 23.9±5.3, 22.5 (14.9–50.1) | 25.3±5.5, 24.1 (13.7–52.3) | <0.001 |
| Gravidity | 2.3±1.4, 2 (1–9) | 2.1±1.2, 2 (1–10) | <0.001 |
| Maternal education years | 9.6±1.7, 10 (3–13) | 10±1.7, 10 (3–13) | <0.001 |
| Household income (Rands b) | 802.4±609.8, 666.7 (71.4–3000) | 853.1±595.1, 750 (45.5–6000) | 0.020c |
| Edinburgh Depression Score d | 13.6±6.1, 14 (0–30) | 12.9±5.9, 13 (0–30) | 0.014 |
| Daily cigarettes | 4.7±3.7, 4 (0–20.5) | 4.3±3.7, 3.6 (0–53) | 0.040 c |
| Birth weight (g) | 2244.1±626.1, 2330 (460–4440) | 3097.2±451, 3080 (1160–5740) | <0.001 |
| Birth weight Z-score | −0.3±1, −0.2 (−6.3 to 3.2) | −0.4±1, −0.4 (–5.7 to 4.1) | 0.007 |
| Birth weight centile | 42.8±26.8, 41.7 (0–99.9) | 38.9±28.1, 34.2 (0–100) | 0.003 |
| Days kept in hospital | 5.5±12.9, 1 (0–97) | 0.9±1.5, 0 (0–23) | <0.001 |
| P value (χ2) | |||
| Marital status: married | 101 (20.0) | 968 (23.7) | 0.078 |
| Poor housing e | 140 (33.5) | 1208 (30.2) | 0.164 |
| Maternal underweight | 40 (8.1) | 201 (5.0) | 0.008 |
| Maternal obesity | 61 (12.3) | 745 (18.7) | <0.001 |
| Telephone | 336 (80.8) | 3592 (89.6) | <0.001 |
| Water at home | 310 (74.3) | 3302 (82.4) | <0.001 |
| Drinking of alcohol during pregnancy | 336 (68.7) | 2738 (67.3) | 0.536 |
| Smoking of cigarettes during pregnancy | 376 (76.9) | 2782 (68.4) | <0.001 |
| Use of marijuana | 59 (12.7) | 450 (11.1) | 0.302 |
| Use of methamphetamine | 43 (9.3) | 231 (5.7) | 0.004 |
| Primigravida | 186 (41.0) | 1718 (42.5) | 0.533 |
| Previous stillbirth | 17 (6.3) | 37 (1.5) | <0.001 |
| Previous preterm birth | 81 (30.2) | 278 (12.0) | <0.001 |
| Placenta abruption f | 15 (3.0) | 4 (0.1) | <0.001 |
| Pre-eclampsia f | 13 (2.6) | 80 (2.0) | 0.384 |
| Eclampsia f | 3 (0.6) | 6 (0.2) | 0.075 |
| Diabetes f | 7 (1.4) | 8 (0.2) | <0.001 |
| Gestational hypertension f | 34 (6.8) | 332 (8.3) | 0.247 |
| LBW infants | 310 (61.3) | 307 (7.5) | <0.001 |
| SGA infants | 64 (12.9) | 776 (19.0) | <0.001 |
| Infant in NICU | 125 (27.3) | 122 (3.1) | <0.001 |
Abbreviations: ANOVA, analysis of variance; BMI, body mass index; LBW, low birth weight; NICU, neonatal intensive care unit; SD, standard deviation; SGA, small for gestational age; SPTB, spontaneous preterm birth; STB, spontaneous term birth.
a
Values are given as mean ± SD, median (range), or number (percentage).
b
1 USD = 15.22 Rands.
c
Mann–Whitney U test.
d
Validated.
e
Small model toy house (Wendy), informal shack, shelter, trailer.
f
Current pregnancy.