Preterm Birth, Low Gestational Age, Low Birth Weight, Parity, and Other Determinants of Breech Presentation: Results from a Large Retrospective Population-Based Study

Table 1

Distribution and corresponding odds ratios of cases with vertex and breech presentation according to selected factors. Lombardy, Italy.

	Presentation				Unadjusted logistic regression			Adjusted logistic regression
	Vertix		Breech			95% CI			95% CI
	N	%	N	%	OR	Lower	Upper	OR	Lower	Upper
Maternal age
<25	43408	97.0	1344	3.0	1+			1+
25–29	90850	96.6	3165	3.4	1.12	1.05	1.20	1.23	1.15	1.31
30–34	140980	96.1	5750	3.9	1.32	1.24	1.40	1.50	1.41	1.60
35–39	110433	95.9	4763	4.1	1.39	1.31	1.48	1.67	1.56	1.79
40+	29461	95.3	1448	4.7	1.59	1.47	1.71	1.84	1.69	2.00
Maternal education
University	118047	96.1	4844	3.9	1+			1+
High school degree	179993	96.1	7367	3.9	1.00	0.96	1.04	1.08	1.04	1.12
Primary/intermediate school or no education	116464	96.5	4247	3.5	0.89	0.85	0.93	1.09	1.04	1.14
Citizenship
Italian	293243	95.9	12379	4.1	1+			1+
Foreign	123054	96.7	4146	3.3	0.80	0.77	0.83	0.95	0.91	0.99
Albanian	11036	96.6	388	3.4	0.83	0.75	0.92
Chinese	6277	97.5	163	2.5	0.62	0.53	0.72
Egyptian	7189	97.2	205	2.8	0.68	0.59	0.78
Moroccan	16206	97.1	478	2.9	0.70	0.64	0.77
Romanian	14371	95.8	623	4.2	1.03	0.95	1.11
Other	67975	96.7	2289	3.3	0.80	0.76	0.83
Previous delivery
0	210014	95.2	10689	4.8	1+			1+
1	147313	97.2	4239	2.8	0.57	0.55	0.59	0.47	0.45	0.49
2+	51874	97.5	1311	2.5	0.50	0.47	0.53	0.40	0.37	0.43
Previous parity in unidentified number	6932	96.1	282	3.9	0.80	0.71	0.90	0.55	0.48	0.63
Previous caesarean
Nulliparous	210014	95.2	10689	4.8	2.15	2.07	2.24	NE
0	133385	97.7	3156	2.3	1+			1+
1	38316	95.5	1821	4.5	2.01	1.89	2.13	1.81	1.70	1.93
2+	7808	96.4	291	3.6	1.58	1.39	1.78	1.60	1.40	1.82
Previous spontaneous or induced abortion
No	294791	96.1	11849	3.9	1+			1+
Yes	121506	96.3	4676	3.7	0.96	0.92	0.99	1.05	1.01	1.09
Mode of conception
Spontaneous conception	408332	96.2	15959	3.8	1+			1+
Assisted conception	7965	93.4	566	6.6	1.82	1.67	1.98	1.14	1.04	1.25
Gestational age (weeks)
23-24	176	69.0	79	31.0	12.81	9.82	16.71	16.08	12.18	21.22
25-26	294	70.0	126	30.0	12.23	9.92	15.07	14.27	11.42	17.82
27-28	468	73.6	168	26.4	10.24	8.58	12.23	11.45	9.48	13.83
29-30	770	79.8	195	20.2	7.22	6.17	8.46	8.07	6.82	9.54
31-32	1532	86.9	230	13.1	4.28	3.72	4.92	4.67	4.03	5.42
33-34	3948	88.6	506	11.4	3.66	3.33	4.02	3.76	3.41	4.16
35-36	14626	91.3	1393	8.7	2.72	2.57	2.88	2.68	2.52	2.84
37+	394483	96.6	13828	3.4	1+			1+
Sex
Male	215446	96.5	7781	3.5	1+			1+
Female	200847	95.8	8743	4.2	1.21	1.17	1.24	1.22	1.18	1.26
Small for gestational age
No	377022	96.4	14181	3.6	1+			1+
Yes	39271	94.4	2343	5.6	1.59	1.52	1.66	1.34	1.27	1.40
Total	416297	96.2	16525	3.8

In some cases the sum does not add up to the total because of missing values.NE = Item risk not estimated because of collinearity with “previous deliveries” variable.^°Including all the above listed variables.