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 10 1.8 (0.9,3.3) NA
  Atrial septal defect 943 167.3 (156.8,178.3) NA
  Atrioventricular septal defect 31 5.5 (3.7,7.8) NA
  Coarctation of the aorta 27 4.8 (3.2,7.0) NA
  Common truncus 13 2.3 (1.2,3.9) NA
  Double outlet right ventricle 7 1.2 (0.5,2.6) NA
  Ebstein anomaly 9 1.6 (0.7,3.0) NA
  Hypoplastic left heart syndrome 8 1.4 (0.6,2.8) NA
  Inerrupted aortic arch 32 5.7 (3.9,8.0) NA
  Pulmonary valve atresia and stenosis 71 12.6 (9.8,15.9) NA
  Single ventricle 8 1.4 (0.6,2.8) NA
  Teratology of fallot 32 5.7 (3.9,8.0) NA
  Total anomalous pulmonary venous sonnection - - NA
  Transposition of the great arteries 17 3.0 (1.8,4.8) NA
  Tricuspid valve atresia and stenosis - - NA
  Ventricular septal defect 555 98.5 (90.4,107.0) NA
Central Nervous System
  Anencephalus 7 1.2 (0.5,2.6) 0.3929 1.0000 2.8 0.5 (0.1,1.3)
  Spina bifida without anencephalus 18 3.2 (1.9,5.0) 0.5946 0.9999 14.2 2.5 (1.5,4.2)
  Encephalocele 11 2.0 (1.0,3.5) 0.3778 1.0000 4.5 0.8 (0.3,1.8)
  Holoprosencephaly 77 13.7 (10.8,17.1) NA
Chromosomal
  Deletion 22 q11 6 1.1 (0.4,2.3) NA
  Trisomy 13 - - 0.5000 1.0000 1.5 0.3 (0.0,1.0)
  Trisomy 18 12 2.1 (1.1,3.7) 0.5833 1.0000 7.0 1.2 (0.5,2.6)
  Trisomy 21 (Down syndrome) 91 16.1 (13.0,19.8) 0.8182 0.9999 79.9 14.2 (11.3,17.5)
  Turner syndrome* - - NA
Ear
  Anotia / microtia 23 4.1 (2.6,6.1) NA
Eye
  Anophthalmia / microphthalmia - - NA
  Congenital cataract 26 4.6 (3.0,6.8) NA
Gastrointestinal
  Biliary atresia 7 1.2 (0.5,2.6) NA
  Esophageal atresia / tracheoesophageal fistula 14 2.5 (1.4,4.2) NA
  Rectal and large intestinal atresia / stenosis 46 8.2 (6.0,10.9) NA
  Small intestinal atresia / stenosis 34 6.0 (4.2,8.4) NA
Genitourinary
  Bladder exstrophy - - NA
  Cloacal exstrophy - - NA
  Congenital posterior urethral valves 53 9.4 (7.0,12.3) NA
  Hypospadias** 334 115.6 (103.5,128.7) 0.8618 0.9996 297.9 103.1 (91.8,115.2)
  Renal agenesis / hypoplasia 41 7.3 (5.2,9.9) NA
Musculoskeletal
  Clubfoot 198 35.1 (30.4,40.4) NA
  Craniosynostosis 8 1.4 (0.6,2.8) NA
  Diaphragmatic hernia 22 3.9 (2.4,5.9) 0.7083 0.9999 18.6 3.3 (2.0,5.0)
  Gastroschisis 46 8.2 (6.0,10.9) 0.6174 1.0000 31.0 5.5 (3.7,7.6)
  Limb deficiencies 54 9.6 (7.2,12.5) NA
  Omphalocele 72 12.8 (10.0,16.1) 0.1856 1.0000 13.5 2.4 (1.4,3.9)
Orofacial
  Choanal atresia 20 3.5 (2.2,5.5) NA
  Cleft lip with celft palate 69 12.2 (9.5,15.5) NA
  Cleft lip alone 17 3.0 (1.8,4.8) NA
  Cleft palate alone 69 12.2 (9.5,15.5) NA
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

Note: The Alaska Birth Defects Registry (ABDR) was established and operates under Alaska statute 7 AAC 27.012. Statue allows reports to by age six years of a child. This report includes defects reported before the 3rd 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:**
Cleft Lip (CL), Cleft Palate (CP), and Cleft Lip and Palate (CLP) are coded to be mutually exclusive groups.Because an individual can be reported multiple times and for any condition, this coding ensures that for these cleft conditions the classifications conform to the expectation of being mutually exclusive.

Hypospadias is restricted to male births (N = 28889).
Turner Syndrome is restricted to female births (N = 27481).

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 May 25, 2018. Available at: https://rpubs.com/AK_ABDR/Prevalence10_14.

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

Updated: May 25, 2018
Code source: R:\ABDR\Analysis_New\Published Data\Prevalence10.14.Rmd