Report and Estimated Defect Prevalence Estimates (per 10,000 live births)
Defect Reports Report Prevalence (95%CI) PPV NPV Estimated Defects Defect Prevalence (95%CI)
Cardiovascular
  Aortic valve stenosis 12 2.4 (1.3,4.2) NA
  Atrial septal defect 1069 216.2 (203.4,229.5) NA
  Atrioventricular septal defect 24 4.9 (3.1,7.2) NA
  Coarctation of the aorta 29 5.9 (3.9,8.4) 0.5775 1.0000 16.9 3.4 (2.0,5.3)
  Common truncus - - 0.2174 1.0000 0.9 0.2 (0.0,0.7)
  Double outlet right ventricle - - 0.4483 1.0000 0.6 0.1 (0.0,0.7)
  Ebstein anomaly - - 0.8333 1.0000 3.3 0.7 (0.2,1.8)
  Hypoplastic left heart syndrome - - 0.6471 1.0000 2.7 0.6 (0.1,1.5)
  Interrupted aortic arch 7 1.4 (0.6,2.9) 0.1765 1.0000 2.0 0.4 (0.1,1.5)
  Pulmonary valve atresia and stenosis 82 16.6 (13.2,20.6) 0.7308 1.0000 59.9 12.1 (9.3,15.4)
  Single ventricle - - 0.2414 1.0000 0.5 0.1 (0.0,0.7)
  Teratology of fallot 13 2.6 (1.4,4.5) 0.6324 1.0000 8.2 1.7 (0.8,3.2)
  Total anomalous pulmonary venous connection 9 1.8 (0.8,3.5) 0.8400 1.0000 7.6 1.5 (0.7,2.9)
  Transposition of the great arteries 8 1.6 (0.7,3.2) 0.6071 1.0000 5.3 1.1 (0.4,2.4)
  Tricuspid valve atresia and stenosis - - 0.4167 1.0000 0.8 0.2 (0.0,0.7)
  Ventricular septal defect 451 91.2 (83.0,100.0) NA
Central Nervous System
  Anencephalus 9 1.8 (0.8,3.5) 0.3929 1.0000 3.5 0.7 (0.2,1.8)
  Spina bifida without anencephalus 27 5.5 (3.6,7.9) 0.5946 0.9999 19.1 3.9 (2.5,6.0)
  Encephalocele - - 0.3778 1.0000 1.4 0.3 (0.0,1.1)
  Holoprosencephaly 43 8.7 (6.3,11.7) NA
Chromosomal
  Deletion 22 q11 8 1.6 (0.7,3.2) NA
  Trisomy 13 6 1.2 (0.4,2.6) 0.5000 1.0000 3.0 -
  Trisomy 18 6 1.2 (0.4,2.6) 0.5833 1.0000 3.5 0.7 (0.2,1.8)
  Trisomy 21 (Down syndrome) 80 16.2 (12.8,20.1) 0.8182 0.9999 70.3 14.2 (11.2,17.9)
  Turner syndrome* 7 2.9 (1.2,6.0) NA
Ear
  Anotia / microtia 30 6.1 (4.1,8.7) NA
Eye
  Anophthalmia / microphthalmia 11 2.2 (1.1,4.0) 0.1818 1.0000 2.0 0.4 (0.0,1.5)
  Congenital cataract 27 5.5 (3.6,7.9) NA
Gastrointestinal
  Biliary atresia 20 4.0 (2.5,6.2) NA
  Esophageal atresia / tracheoesophageal fistula 15 3.0 (1.7,5.0) NA
  Rectal and large intestinal atresia / stenosis 34 6.9 (4.8,9.6) NA
  Small intestinal atresia / stenosis 29 5.9 (3.9,8.4) NA
Genitourinary
  Bladder exstrophy - - NA
  Cloacal exstrophy - - NA
  Congenital posterior urethral valves 13 2.6 (1.4,4.5) NA
  Hypospadias** 203 79.7 (69.1,91.4) 0.8618 0.9996 183.8 72.1 (62.1,83.0)
  Renal agenesis / hypoplasia 44 8.9 (6.5,11.9) NA
Musculoskeletal
  Clubfoot 142 28.7 (24.2,33.8) 0.3000 1.0000 43.7 8.8 (6.5,11.7)
  Craniosynostosis 163 33.0 (28.1,38.4) NA
  Diaphragmatic hernia 24 4.9 (3.1,7.2) 0.7083 0.9999 19.6 4.0 (2.5,6.0)
  Gastroschisis 35 7.1 (4.9,9.8) 0.6174 1.0000 23.9 4.8 (3.1,7.0)
  Limb deficiencies 40 8.1 (5.8,11.0) 0.5476 0.9999 25.4 5.1 (3.4,7.5)
  Omphalocele 96 19.4 (15.7,23.7) 0.1856 1.0000 18.0 3.6 (2.2,5.5)
Orofacial
  Choanal atresia 15 3.0 (1.7,5.0) NA
  Cleft lip with celft palate*** 50 10.5 (3, 34.6) 0.6600 1.0000 33.6 2.6 (1.46, 4.26)
  Cleft lip alone*** 43 8.6.0 (1.2 26.7) 0.82 (0.32, 1.96)
  Cleft palate alone*** 89 18.2 (5.2, 42) 0.5610 0.9998 60.7 2.5 (1.46, 4.26)
Ref: NA = Information not available as of publication; '-' = supressed for cell counts <6; 95% CI = 95% Confidence Interval; g = grams, PPV = Positive Predictive Value; NPV = Negative Predictive value

*per 10,000 live female births

**per 10,000 live male births

***All cleft condition defect estimates include additional adjustments (not displayed here) for intra-conditional misclassification (i.e. individuals reported for the wrong, or multiple cleft conditions)

Note: The Alaska Birth Defects Registry (ABDR) was established and operates under Alaska statute 7 AAC 27.012. Statue allows reports to by age three years of a child. This report includes defects reported before the third birthday.

Column descriptions:
Defect = The Nationally reportable birth defect grouping name.
Reports = Unless otherwise noted, the number of unique reports of defect received by ABDR during the specified birth year(s). Each report represents a unique child with specified defect.
Report Prevalence (95% CI) = The number of reported defects divided by the number of Alaska resident in-state births (Children can be reported multiple times. they are counted only once for each condition).
PPV = The probability of being defect positive given being reported for the defect.
NPV = The probability of being defect negative given not being reported for the defect.
Estimated Defects = The estimated number of defects based on the report prevalence, PPV, and 1-NPV.
Defect Prevalence (95% CI) = The estimated defect prevalence calculated using a Bayesian approach based on the reported prevalence, PPV and 1-NPV (see formula below).

*Through medical records review and case confirmation of a random sample of reported cases, the defect prevalence is calculated as:

\[PPV (Positive Predictive Value) = p(defect)|report)\] \[NPV (Negative Predictive Value) = p(\overline{defect}|\overline{report})]\]

\[p(defect) \approx [p(report)\cdot PPV]+[p(\overline{report})\cdot 1-NPV)]\]

Defect prevalence estimates are a more accurate estimation of the actual diagnosed prevelance of birth defects compared to the reported prevelance estimates in Alaska. ABDR obtains reports from medical providers using International Classification of Disease (ICD) codes that are extracted from individual systems which when aggregated may not reflect true diagnostics. Caution should be used when interpreting and comparing the reported prevalence estimates with national estimates.

Condition Notes:

Hypospadias is restricted to male births (N = 25483).
Turner Syndrome is restricted to female births (N = 23968).

Resources:
National Birth Defects Prevention Network
Centers for Diesase Control and Prevention

Suggested Citation

State of Alaska Department of Health and Social Services, Division of Public Health, Section of Women’s, Children’s, and Family Health. Alaska Birth Defects Registry Nationally reportable major congenital anomalies. Updated April 12, 2024. Available at: https://rpubs.com/AK_ABDR/Prevalence.

Contact
Alaska Birth Defects Registry (ABDR)
3601 C Street, Suite 358
Anchorage, AK 99503
(907) 269-3400 phone
(907) 754-3529 fax

Updated: April 12, 2024
Code source: R:\ABDR\Analysis_New\Published Data\Prevalence15_19.Rmd

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