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 14 2.7 (1.5,4.6) NA
  Atrial septal defect 882 172.1 (161.0,183.9) NA
  Atrioventricular septal defect 21 4.1 (2.5,6.3) NA
  Coarctation of the aorta 27 5.3 (3.5,7.7) 0.5775 1.0000 15.8 3.1 (1.8,4.8)
  Common truncus - - 0.2174 1.0000 0.9 0.2 (0.0,0.7)
  Double outlet right ventricle - - 0.4483 1.0000 1.5 0.3 (0.0,1.1)
  Ebstein anomaly - - 0.8333 1.0000 2.5 0.5 (0.1,1.4)
  Hypoplastic left heart syndrome - - 0.6471 1.0000 2.1 0.4 (0.1,1.4)
  Interrupted aortic arch 11 2.1 (1.1,3.8) 0.1765 1.0000 2.8 0.5 (0.1,1.4)
  Pulmonary valve atresia and stenosis 71 13.9 (10.8,17.5) 0.7308 1.0000 51.9 10.1 (7.6,13.1)
  Single ventricle - - 0.2414 1.0000 0.7 0.1 (0.0,0.7)
  Teratology of fallot 12 2.3 (1.2,4.1) 0.6324 1.0000 7.6 1.5 (0.7,2.8)
  Total anomalous pulmonary venous connection 9 1.8 (0.8,3.3) 0.8400 1.0000 7.6 1.5 (0.7,2.8)
  Transposition of the great arteries 7 1.4 (0.5,2.8) 0.6071 1.0000 4.7 0.9 (0.3,2.0)
  Tricuspid valve atresia and stenosis - - 0.4167 1.0000 0.8 0.2 (0.0,0.7)
  Ventricular septal defect 416 81.2 (73.6,89.4) NA
Central Nervous System
  Anencephalus 11 2.1 (1.1,3.8) 0.3929 1.0000 4.3 0.8 (0.3,2.0)
  Spina bifida without anencephalus 24 4.7 (3.0,7.0) 0.5946 0.9999 17.4 3.4 (2.1,5.3)
  Encephalocele - - 0.3778 1.0000 1.8 0.4 (0.0,1.1)
  Holoprosencephaly 46 9.0 (6.6,12.0) NA
Chromosomal
  Deletion 22 q11 8 1.6 (0.7,3.1) NA
  Trisomy 13 - - 0.5000 1.0000 1.5 -
  Trisomy 18 - - 0.5833 1.0000 2.3 0.5 (0.1,1.4)
  Trisomy 21 (Down syndrome) 82 16.0 (12.7,19.9) 0.8182 0.9999 72.1 14.1 (11.2,17.7)
  Turner syndrome* 6 2.4 (0.9,5.2) NA
Ear
  Anotia / microtia 28 5.5 (3.6,7.9) NA
Eye
  Anophthalmia / microphthalmia 13 2.5 (1.4,4.3) NA
  Congenital cataract 21 4.1 (2.5,6.3) NA
Gastrointestinal
  Biliary atresia 23 4.5 (2.8,6.7) NA
  Esophageal atresia / tracheoesophageal fistula 10 2.0 (0.9,3.6) NA
  Rectal and large intestinal atresia / stenosis 31 6.0 (4.1,8.6) NA
  Small intestinal atresia / stenosis 30 5.9 (4.0,8.4) NA
Genitourinary
  Bladder exstrophy - - NA
  Cloacal exstrophy - - NA
  Congenital posterior urethral valves 12 2.3 (1.2,4.1) NA
  Hypospadias** 231 87.6 (76.7,99.7) 0.8618 0.9996 208.3 79.0 (68.9,90.4)
  Renal agenesis / hypoplasia 42 8.2 (5.9,11.1) NA
Musculoskeletal
  Clubfoot 143 27.9 (23.5,32.9) 0.3000 1.0000 44.0 8.6 (6.4,11.5)
  Craniosynostosis 146 28.5 (24.1,33.5) NA
  Diaphragmatic hernia 20 3.9 (2.4,6.0) 0.7083 0.9999 16.9 3.3 (1.9,5.1)
  Gastroschisis 37 7.2 (5.1,10.0) 0.6174 1.0000 25.2 4.9 (3.3,7.2)
  Limb deficiencies 47 9.2 (6.7,12.2) NA
  Omphalocele 184 35.9 (30.9,41.5) 0.1856 1.0000 34.3 6.7 (4.8,9.3)
Orofacial
  Choanal atresia 16 3.1 (1.8,5.1) NA
  Cleft lip with celft palate*** 50 9.2 (2.5, 23.7) 5.18 (2.96, 8.46)
  Cleft lip alone*** 43 7.9.0 (2.5 20.2) 0.3913 1.0000 18.2 1.62 (0.6, 3.78)
  Cleft palate alone*** 106 22.2 (11.1, 39.5) 0.5610 0.9998 70.7 5.88 (3.5, 9.34)
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 = 26357).
Turner Syndrome is restricted to female births (N = 24885).

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 June 06, 2023. 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: June 06, 2023
Code source: R:\ABDR\Analysis_New\Published Data\Prevalence15_19.Rmd

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