Table 3.
Association of Maternal Thyroid Disease with Selected Birth Defects, National Birth Defects Prevention Study, 1997–2004
| Isolated cases | All casesa | |||
|---|---|---|---|---|
|
|
|
|||
| Thyroid disease/unexposed | OR (CI)b | Thyroid disease/unexposed | OR (CI)b | |
| Central nervous system | ||||
| Anencephaly | 5/263 | 1.0 (0.4–2.5) | 6/288 | 1.1 (0.5–2.6) |
| Spina bifida | 11/519 | 1.1 (0.6–2.1) | 12/570 | 1.1 (0.6–2.0) |
| Encephalocele | 3/83 | 1.9 (0.4–5.8) | 3/112 | 1.4 (0.3–4.3) |
| Dandy-Walker | 2/51 | 2.0 (0.2–7.9) | 4/85 | 2.4 (0.6–6.7) |
| Holoprosencephaly | 3/48 | 3.2 (0.6–10.3) | 3/70 | 2.2 (0.4–6.9) |
| Hydrocephaly | 11/171 | 3.6 (1.9–6.9) | 13/247 | 2.9 (1.6–5.2) |
| Eye | ||||
| Anophthalmia/microphthalmia | 0/72 | — | 3/124 | 1.3 (0.2–3.9) |
| Congenital cataracts | 2/140 | — | 2/156 | — |
| Ear | ||||
| Anotia/microtia | 2/261 | — | 4/353 | 0.6 (0.2–1.7) |
| Orofacial clefts | ||||
| CPO | 18/643 | 1.3 (0.8–2.2) | 19/799 | 1.2 (0.7–1.9) |
| CL/P | 24/1329 | 1.0 (0.6–1.5) | 27/1500 | 1.0 (0.6–1.5) |
| Gastrointestinal | ||||
| Esophageal atresia | 1/157 | — | 5/372 | 0.6 (0.2–1.5) |
| Small intestinal atresia | 5/192 | 1.7 (0.7–4.2) | 7/227 | 2.0 (0.9–4.3) |
| Duodenal atresia | 1/65 | 0.9 (0.1–6.3) | 1/106 | 0.5 (0.1–3.8) |
| Anorectal atresia | 10/244 | 2.4 (1.2–4.6) | 15/532 | 1.6 (0.9–2.7) |
| Genitourinary | ||||
| Hypospadias | 40/989 | 1.6 (1.0–2.5) | 43/1086 | 1.6 (1.0–2.5) |
| Renal agenesis | 1/62 | — | 1/91 | — |
| Musculoskeletal | ||||
| Longitudinal limb defects | 5/126 | 2.1 (0.8–5.2) | 6/228 | 1.5 (0.6–3.5) |
| Transverse limb defects | 7/303 | 1.2 (0.6–2.7) | 8/358 | 1.2 (0.6–2.5) |
| Diaphragmatic hernia | 2/343 | — | 4/426 | 0.5 (0.1–1.3) |
| Omphalocele | 5/132 | 1.9 (0.8–4.9) | 7/218 | 1.7 (0.8–3.7) |
| Gastroschisis | 6/540 | 1.8 (0.7–4.2) | 6/593 | 1.6 (0.7–3.8) |
| Other | ||||
| Amniotic band sequence | — | — | 0/150 | — |
Controls: 110 maternal thyroid disease/5743 unexposed; for crude odds ratios: 111 maternal thyroid disease/5764 unexposed.
Both cases with isolated anomalies and those with additional defects are included in this group.
For defects with more than five exposed cases, estimates were adjusted for mother’s state of residence at the time of infant’s birth, age, and race/ethnicity. Asymptotic confidence intervals were calculated. Additional covariates were included in analysis of anencephaly (plurality), spina bifida (body mass index [BMI]), hypospadias (gestational diabetes, maternal use of fertility medications or procedures), gastroschisis (BMI and smoking). Control n’s were slightly lower for analysis of case groups that were adjusted for BMI and smoking because of missing values for these covariates. For the analysis of hypospadias, the number of male controls was 52 and 2887 with and without maternal thyroid disease, respectively. Crude odds ratios with exact 95% confidence intervals are presented for defects with 3–4 exposed cases. Estimates are not presented for analyses based on <3 exposed cases.
CPO, cleft palate only; CL/P, cleft lip with or without cleft palate; OR, odds ratio; CI, confidence interval.