Section V - Comparison of Selected Malformation Prevalence with Other Birth Defects Registries

Introduction to Table

The CMR relies on reports from hospitals and physicians for case ascertainment. Underreporting is an obvious concern, and the CMR monitors hospital reporting and follows up if there appears to be underreporting. In this section, CMR live birth prevalence are compared with the prevalences of two other registries, the Metropolitan Atlanta Congenital Defects Program (MACDP)1 and the California Birth Defects Monitoring Program (CBDMP)2. These two registries send data collection specialists to hospitals to identify and abstract records of children with malformations. To help evaluate possible underreporting, CMR prevalences of selected malformations, defined using BPA codes, were compared with prevalence from these two registries. (See Appendix 4 for further information on these BPA codes.) These two programs follow children through one year of age. The CMR follows children through two years; however, more than 95% of cases are reported in the first year. Most of the malformations in this table are recognized at birth. The exceptions are fetal alcohol syndrome and some cardiac malformations.

The most striking difference among the registries is the low prevalence of anencephaly in New York State. This probably is largely due to the inclusion of stillborn infants in the MACDP and the CBDMP. The CMR includes only live born children (see Section VI, Current Topics). Underreporting is not the only reason for possible differences. The prevalences of some birth defects differ by race. True geographic differences may also exist3.

Section V
Comparison of Selected Malformation Prevalence
with two other Birth Defects Registries
MACDP
Code
 
Malformation
CMR
1995
MACDP4
1995
CBDMP4
1995
A01 Anencephalus 0.6 2.2 2.9
A04 Spina bifida 3.7 1.2 3.6
A15 Hydrocephalus 7.8 5.0 5.9
A13 Encephalocele 1.0 1.2 0.9
A16 Microcephalus 5.8 5.2 -.-
B01 An/Microphthalmos 1.7 3.5 2.7
D01 Common truncus 0.7 0.7 1.1
D02 Trans of great vessels 4.8 4.7 4.6
D03 Tetralogy of Fallot 4.8 2.7 2.9
D05 Ventricular septal defect 34.5 21.6 14.8
D26 Coarctation of aorta 4.1 4.2 4.0
E01 Choanal atresia 1.0 1.2 1.3
E06 Lung agenesis/hypoplasia 3.6 4.5 -.-
F01 Cleft palate 5.8 4.7 5.4
F02 Cleft lip ± cleft palate 7.7 9.9 10.9
F09 Esophageal/tracheoesophageal atresia 2.4 2.5 2.3
F16 Rectal/large intestine atresia 4.2 2.7 4.2
F08 Pyloric stenosis 16.6 7.7 14.2
F17 Hirschsprung's disease 1.8 1.2 1.7
F21 Biliary atresia 0.7 1.0 0.9
H01 Renal agenesis/hypoplasia 3.3 2.0 -.-
H08 Bladder exstrophy 0.2 -.- 0.3
G02 Hypo/epispadias 33.7 33.5 12.9
K01 Reduct deform of upper limb 3.0 4.2 3.1
K02 Reduct deform of lower limb 1.9 2.5 1.2
N01 Diaphragmatic hernia 2.0 1.5 2.7
N02 Omphalocele 1.2 1.5 1.8
N04 Gastroschisis 1.2 2.2 2.2
R01 Down syndrome 10.1 10.7 13.1
R02 Trisomy 13 0.8 2.0 1.1
R03 Trisomy 18 1.0 2.2 2.0
S02 Fetal alcohol syndrome 2.0 3.0 0.9
K05 Amniotic bands 0.3 1.0 1.6

References

  1. Edmonds LD, Layde PM, Levy JM, et al. Congenital malformations surveillance: two American systems. Inter J Epidemiol 1981; 10:247-251.

  2. Grether JK. New California program monitors birth defects. J Perinatology 1985; 5:8-10.

  3. Schulman J, Edmonds LD, McClern AB, et al. Surveillance for and comparison of birth defect prevelences in two geographic areas - United States 1983-1988. In: CDC Surveillance Summaries; March 19, 1993. Morbidity and Mortality Weekly Report 1993; 42(No. SS-1):1-7.

  4. Birth defects surveillance data from selected states, A report from the National Birth Defects Prevention Network. Teratology 1997; 56:115-175.