Preterm Birth: A Prominent Risk Factor for Low Apgar Scores

Table 3

Risk factors for Apgar scores < 7 at 5 minutes. Analyses performed by univariate and multivariate logistic regression.

	Total	AS^5 min < 7		Univariate logistic regression			Multivariate logistic regression
			(%)	OR	95% conf. int.		OR	95% conf. int.
Level of care
Secondary	7011	96	1.37	1.00
Tertiary	13632	273	2.00	1.48	1.17–1.87	0.001	—	—	—
Age (years)
≤26	5387	100	1.86	1.00			1.00
27–30	5976	102	1.71	1.01	0.92–1.10		1.10	0.97–1.24
31–33	4343	72	1.66	1.01	0.84–1.22		1.20	0.93–1.54
≥34	4937	95	1.92	1.02	0.77–1.34	0.897	1.31	0.90–1.91	0.152
Height (cms)
≥175	1800	17	0.94	1.00			1.00
159–174	14992	229	1.53	1.83	1.44–2.32		2.06	1.56–2.72
≤158	2084	60	2.88	3.34	2.06–5.39	<0.001	4.23	2.43–7.39	<0.001
BMI (kg/m^2)
<25	11359	156	1.37	1.00			1.00
25–29.9	4862	84	1.73	1.38	1.19–1.60		1.29	1.08–1.54
≥30	2319	61	2.63	1.91	1.43–2.56	<0.001	1.67	1.17–2.36	0.004
Smoking
No	15784	246	1.56	1.00
Yes	3236	62	1.92	1.25	0.95–1.66	0.113	—	—	—
Thyroid disease
No	18379	290	1.58	1.00
Yes	550	17	3.09	1.99	1.21–3.27	0.007	—	—	—
Type 1 diabetes mellitus
No	18823	302	1.60	1.00
Yes	134	5	3.73	1.21	0.97–5.85	0.059	—	—	—
Inflammatory bowel disease
No	18762	302	1.61	1.00
Yes	194	5	2.58	1.62	0.66–3.96	0.292	—	—	—
Epilepsy
No	18798	303	1.61	1.00
Yes	158	4	2.53	1.59	0.58–4.30	0.366	—	—	—
Parity
0	8418	191	2.27	1.00			1.00
≥1	10602	117	1.10	0.48	0.38–0.60	<0.001	0.34	0.25–0.48	<0.001
Gestational age (weeks)
37 + 0–41 + 6	18251	206	1.13	1.00			1.00
≥42 + 0	1080	26	2.41	2.8	2.6–3.1		2.0	1.7–2.3
32 + 0–36 + 6	1026	45	4.39	8.0	6.8–9.4		3.9	2.9–5.3
28 + 0–31 + 6	149	27	18.1	23	18–29		8	5–12
<28 + 0	111	62	55.9	64	46–88	<0.001	15	8–29	<0.001
Previous cesarean section
No	17796	271	1.52	1.00			1.00
Yes	1224	37	3.02	2.01	1.42–2.84	<0.001	3.66	2.31–5.81	<0.001
Multiple pregnancy
No	20338	336	1.65	1.00			1.00
Yes	305	33	10.82	7.20	4.95–10.49	<0.001	3.57	1.81–7.05	<0.001
Preeclampsia
No	20092	334	1.66	1.00
Yes	551	35	6.35	4.01	2.80–5.74	<0.001	—	—	—
Induction
No	18067	299	1.65	1.00
Yes	2576	70	2.72	1.65	1.27–2.15	<0.001	—	—	—
CTG at admission
Normal	16524	214	1.30	1.00			1.00
Nonnormal	1176	36	3.06	2.47	1.73–3.53	<0.001	1.95	1.45–2.62	<0.001