TABLE 2. Risk of perinatal distress and low Apgar score for two subgroups of intrauterine growth-retarded infants (crude and adjusted analysis for birth weight).

Risk factor	Crude analysis Odds ratio (95% CI)	Adjusted* analysis (by birth weight) Odds ratio (95% CI)
Perinatal distress	5.6 (2.4-13.0)	3.2 (1.4-7.5)
Apgar score 5 min <6	3.0 (1.3-6.2)	1.6 (0.7-3.5)

Rate ratios or odds ratios are calculated comparing the IUGR-low ponderal index group (N=432) with the IUGR-adequate ponderal index group (N=2030). They should be interpreted as increased risk of the low PI-IUGR over the API-IUGR group. No effect: odds ratio = 1.00.

* Logistic regression analysis.

Adapted from Villar J. et al. (22).