TABLE VI.

Characteristics of Nonsyndromic^a Cases With Amelia and by Clinical Phenotype Among 20 Surveillance Programs of the International Clearinghouse for Birth Defects Surveillance and Research

Variables	All casesa (n = 319)a		Cases with isolated amelia (n = 101)		Cases with amelia and MCA (n = 218)
	n	(%)	n	(%)	n	(%)
Sex
Male	167	52.4	61	60.4	106	48.6
Female	110	34.5	35	34.7	75	34.4
Indeterminate	28	8.8	0	0.0	28	12.8
Missing data	14	4.4	5	5.0	9	4.1
Outcome
Live births	172	53.9	62	61.4	110	50.5
Stillbirths	84	26.3	23	22.8	61	28.0
ETOPFA	62	19.4	16	15.8	46	21.1
Missing data	1	0.3	0	0.0	1	0.5
Birth weight among live births (g)
<1,500	26	15.1	6	9.7	20	18.2
1,500–2,499	58	33.7	18	29.0	40	36.4
≥2,500	70	40.7	36	58.1	34	30.9
Missing data	18	10.5	2	3.2	16	14.5
Gestational age among live births (weeks)
< 32	39	22.7	4	6.5	35	31.8
33–36	29	16.9	8	12.9	21	19.1
≥37	97	56.4	46	74.2	51	46.4
Missing data	7	4.1	4	6.5	3	2.7
Previous parity
0	71	22.3	32	31.7	39	17.9
1	102	32.0	25	24.8	77	35.3
≥2	49	15.4	19	18.8	30	13.8
Missing data	97	30.4	25	24.8	72	33.0
Previous spontaneous abortions
0	124	38.9	44	43.6	80	36.7
≥1	27	8.5	11	10.9	16	7.3
Missing data	168	52.7	46	45.5	122	56.0
Plurality
Single	278	87.1	93	92.1	185	84.9
Twin	24	7.5	4	4.0	20	9.2
Triplet	1	0.3	0	0.0	1	0.5
Missing data	16	5.0	4	4.0	12	5.5
Maternal age
<20	38	11.9	11	10.9	27	12.4
20–24	100	31.3	31	30.7	69	31.7
25–29	81	25.4	26	25.7	55	25.2
30–34	60	18.8	25	24.8	35	16.1
≥35	22	6.9	4	4.0	18	8.3
Missing data	18	5.6	4	4.0	14	6.4
Parental age difference
Mother same age or older	32	10.0	14	13.9	18	8.3
Mother 1–2 years younger	26	8.2	11	10.9	15	6.9
Mother 3–4 years younger	30	9.4	14	13.9	16	7.3
Mother >4 years younger	26	8.2	6	5.9	20	9.2
Missing data	205	64.3	56	55.4	149	68.3
Maternal education (years)
<9	27	8.5	10	9.9	17	7.8
≥9	70	21.9	20	19.8	50	22.9
Missing data	222	69.6	71	70.3	151	69.3

^aSyndromic cases (n = 7) were excluded from analysis.