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. 2020 Oct 16;20:628. doi: 10.1186/s12884-020-03328-6

Table 4.

Factors associated with Preterm Birth and Low Birth Weight (n = 760)

Crude Odds Ratio p-value Adjusted Odds Ratio (95% CI) p-value
Preterm Birth
 Maternal age
  Prime fertility age (20–30 years) 1 1
  Teenager (15–19 years) 1.2 0.5 1.2 (0.6–2.3) 0.6
  Middle aged (>  30 years) 1.7 0.02 1.8 (1.1–2.9) 0.01
 Maternal BMI at trimester 1
  Normal BMI (18.5–24.9 kg/m2) 1 1
  Low BMI (<  18.5 kg/m2) 1.4 0.4 0.9 (0.4–2.4) 0.9
  High BMI (25–29.9 kg/m2) 0.6 0.03 0.5 (0.3–0.9) 0.02
  Obese (>  30 kg/m2) 0.6 0.03 0.5 (0.3–0.9) 0.01
Past history of tuberculosis 3.5 0.02 2.0 (0.6–6.6) 0.3
Past history of sexually transmitted infections 2.6 0.2 2.7 (0.6–12.2) 0.2
Syphilis 0.3 0.02 0.4 (0.1–0.9) 0.04
Hypertension
 Normotensive
  Chronic 0.7 0.8 0.8 (0.09–6.7) 0.8
  PIH 1.1 0.9 0.5 (0.06–4.2) 0.5
HIV positive 1.4 0.1 1.4 (1.0–2.2) 0.1
Current Smoker 3.22 0.001 2.7 (1.3–5.8) 0.01
 Delivery Type
  Normal delivery 1 1
  Caesarian section 1.54 0.03 1.7 (1.1–2.7) 0.01
Low Birth Weight
 Weight gain
  Normal 1 1
  High (>  6.3 kg)a 0.74 0.2 0.6 (0.4–1.03) 0.07
 Maternal age
  Prime fertility age (20–30 years) 1 1
  Teenager (15–19 years) 1.7 0.1 1.6 (0.9–3.1) 0.1
  Middle aged (> 30 years) 1.4 0.1 1.7 (1.0–2.9) 0.07
 Maternal BMI at trimester 1
  Normal (18.5–24.9) 1 1
  Low BMI (< 18.5 kg/m2) 1.7 0.2 1.3 (0.5–3.3) 0.5
  High BMI (25–29.9 kg/m2) 0.5 0.01 0.5 (0.3–0.8) 0.01
  Obese (>  30 kg/m2) 0.5 0.02 0.4 (0.2–0.7) 0.002
Past history of sexually transmitted infections 3.3 0.09 4.2 (1.0–18.3) 0.06
Syphilis 0.7 0.4 1.0 (0.6–1.7) 0.9
 Hypertension
  Normotensive 1 1
  Chronic Not available Not available
  PIH 1.4 0.6 1.2 (0.1–10.6) 0.9
HIV Positive 1.2 0.5 1.2 (0.8–2.03) 0.4
 Smoking
  Non-smoker 1 1
  Current-smoker 2.4 0.03 1.9 (0.8–4.3) 0.1
 Delivery Type
  Normal delivery 1 1
  Caesarian section 1.4 0.1 1.7 (1.1–2.7) 0.03

aMean weight gain across the first and third trimester for mothers during this pregnancy

- LBW (Yes = 1, No = 0), with “YES” when LBW < 2500 g

CI Confidence interval; BMI Body mass index; Ref Reference; PIH Pregnancy induced hypertension; HIV Human immunodeficiency virus; NVD Normal vaginal delivery