TABLE VII.

Crude and Adjusted Odds Ratios (OR) With 95% Confidence Intervals (95% CI) for the Association of Various Characteristics Among Multiple Congenital Anomalies Cases (Cases) Versus Isolated Cases (Controls) of Amelia Reported by 20 Surveillance Programs of the International Clearinghouse for Birth Defects Surveillance and Research

	Crude OR	95% CI		Adjusted OR (aOR)a	95% CI
Sex
Male	1.00	Referent		1.00	Referent
Female	1.23	0.74	2.05	1.21	0.71	2.05
Outcome
Live births	1.00	Referent		1.00	Referent
Stillbirths	4.81	1.70	13.66	5.18	1.70	15.73
ETOPFA	2.56	1.26	5.20	3.09	1.41	6.79
Birth weight among live births (g)
<1,500	3.53	1.26	9.84	2.63	0.81	8.47
1,500–2,499	2.35	1.14	4.87	1.64	0.74	3.65
≥2,500	1.00	Referent		1.00	Referent
Gestational age among live births (weeks)
<32	7.89	2.60	23.91	5.40	1.61	18.08
32–36	2.37	0.96	5.86	3.17	1.13	8.92
≥37	1.00	Referent		1.00	Referent
Previous parity
0	1.00	Referent		1.00	Referent
1	2.85	1.39	5.83	1.60	0.68	3.73
≥2	1.49	0.64	3.45	1.06	0.40	2.80
Previous spontaneous abortions
0	1.00	Referent		1.00	Referent
≥1	0.69	0.29	1.66	0.64	0.25	1.69
Plurality
Single	1.00	Referent		1.00	Referent
Twin	2.51	0.83	7.57	2.95	0.92	9.45
Maternal age
<20	1.00	Referent		1.00	Referent
20–24	0.91	0.40	2.06	1.24	0.53	2.90
25–29	0.86	0.37	2.00	1.38	0.56	3.38
30–34	0.57	0.24	1.36	0.91	0.36	2.28
≥35	1.83	0.50	6.66	2.89	0.74	11.21
Parental age difference
Mother same age or older	0.94	0.33	2.68	0.83	0.26	2.64
Mother 1–2 years younger	1.00	Referent		1.00	Referent
Mother 3–4 years younger	0.84	0.29	2.41	0.58	0.18	1.90
Mother >4 years younger	2.44	0.74	8.11	2.91	0.75	11.29

ETOPFA, elective termination of pregnancy for fetal anomalies; aOR, adjusted odds ratio.

OR computed only for the 16 programs reporting ETOPFA; surveillance programs with more than 20% missing data were excluded from the analysis; seven cases with syndromes were excluded from the analysis.

^aAdjustments were made for tertiles of percentage of MCA cases in each program.