Epidemiology of oesophageal atresia and tracheo-oesophageal fistula in Hawaii, 1986-2000.

The most common major birth defects affecting the oesophagus and trachea are oesophageal atresia (OA) and tracheo-oesophageal fistula (TOF). Epidemiological information on OA and/or TOF in the USA has been derived from only a few populations. Sixty-one cases of OA or TOF were identified through a population-based birth defects registry in Hawaii during 1986-2000. The relationship between various clinical and demographic factors and OA or TOF were examined. The rate of OA or TOF was 2.2 per 10,000 live births. The cases were 67.2% OA with TOF, 21.3% TOF alone, and 11.5% OA alone. Risk of OA or TOF was significantly higher among multiple births and live births with low birth weight and gestational age. The risk of OA or TOF was significantly higher for whites. The rate of OA or TOF was consistent with that reported elsewhere. The risk of the defects differed significantly between the major racial/ethnic groups in Hawaii. The impact of many factors on OA or TOF in Hawaii was similar to that reported elsewhere.

Population-based study of small intestinal atresia and stenosis, Hawaii, 1986-2000.

Atresia and stenosis are some of the most common birth defects affecting the small intestine. Few population-based studies have examined the epidemiology of small intestinal atresia/stenosis. Eighty-two cases of small intestinal atresia/stenosis were identified through a population-based birth defects registry in Hawaii during 1986-2000. The relationships of various clinical and demographic factors with small intestinal atresia/stenosis and duodenal atresia/stenosis were examined. The small intestinal atresia/stenosis and duodenal atresia/stenosis rates were 2.9 per 10,000 live births [95% confidence interval (CI) 2.3-3.6] and 1.3 per 10,000 live births (95% CI 1.0-1.9), respectively. No secular trend was observed (P = 0.067 and 0.090, respectively). Maternal age risk for small intestinal atresia/stenosis was U-shaped, while duodenal atresia/stenosis rates were highest with maternal age of 35 years or more. Small intestinal atresia/stenosis was substantially more common among Far East Asians than Caucasians [rate ratio (RR) 1.96, 95% CI 1.24-2.94]. Duodenal atresia/stenosis risk was higher in Hawaii County than in Honolulu County (RR 2.55, 95% CI 1.10-5.02). Small intestinal atresia/stenosis was also associated with low birth weight (RR 11.50, 95% CI 8.05-15.92), low gestational age (RR 8.60, 95% CI 6.34-11.41) and multiple births (RR 3.79, 95% CI 1.39-8.24). In conclusion, this study found associations between small intestinal atresia/stenosis and maternal age, maternal race/ethnicity, county of residence, birth weight, gestational age and plurality, but not delivery period. Many of the associations between small intestinal atresia/stenosis and other factors noted in this investigation were similar to those reported by other studies.

Residence, delivery and referral patterns of infants and fetuses with birth defects delivered in Hawaii, 1986-1999.

Information on residence, delivery and referral patterns is useful to a birth defects program for allocation of resources, predicting where deliveries may have occurred, and estimating the impact of altering geographic inclusion criteria. The purpose of this study was to describe the residence, delivery and referral patterns for infants and fetuses with birth defects delivered in Hawaii. Data were obtained from the Hawaii Birth Defects Program and included birth defects cases delivered between 1986 and 1999 with known delivery residence and place of delivery. Of 12,873 total cases, 171 (1%) were delivered to out-of-state residents. Of the remaining 12,702 cases delivered to residents in the four Counties of Hawaii, 9905 (78%) were to City and County of Honolulu residents and 2797 (22%) were to residents of Hawaii, Kauai and Maui Counties. Of the cases delivered to City and County of Honolulu residents, 9903 were delivered in that County. Of the cases delivered to residents of the other three Counties, 591 (21%) were referred to the City and County of Honolulu for delivery, and 1602 (57%) were referred to the City and County of Honolulu for any reason. Honolulu delivery referral rates and total referral rates for cases delivered to Hawaii, Kauai and Maui County residents were higher with prenatal diagnosis of a birth defect (59 and 87%, respectively) and elective termination (70 and 85%, respectively), and varied among 53 different types of birth defect (0-83% and 23-100%, respectively).

Inclusion of early fetal deaths in a birth defects surveillance system.

This investigation evaluated the impact of collecting data on early fetal deaths (less than 20 weeks' gestation) on a birth defects surveillance system. Data were obtained from the Hawaii Birth Defects Program (HBDP), a statewide registry for Hawaii with active case ascertainment methodology. In 1986 through 1997, 257 early fetal deaths with birth defects were identified, representing 2.2% of the total birth defects cases. Two hundred sixteen (84.1%) of the early fetal deaths had chromosomal defects (mainly trisomies, polyploidies, and Turner syndrome) and 59 (23.0%) had structural defects. Most (65.4%) of the early fetal deaths with chromosomal defects occurred at 8-12 weeks' gestation, and 62.3% of the early fetal deaths with structural defects occurred at 16-19 weeks' gestation. For half of the 26 specific birth defects examined, early fetal deaths accounted for at least 4% of all cases. The proportion of total birth defects cases accounted for by early fetal deaths increased over the 12-year period of the study (p = 0.003). Most of this secular trend appeared to result from an increase over time in early fetal deaths where a birth defect was prenatally detected (p = 0.004). Although ascertainment of early fetal deaths is not believed to be complete, their inclusion in a birth defects registry may be beneficial because of confusion about the pregnancy outcome and/or gestational age reported in the medical record, their importance in cluster investigations, and their contribution to birth defects prevention strategies.

Birth defects prevalence among infants of Persian Gulf War veterans born in Hawaii, 1989-1993.

BACKGROUND: Gulf War veterans (GWVs) have expressed concern about possible teratogenic exposures. However, epidemiologic studies on birth defects prevalence among their progeny have been limited to military hospitals, anomalies diagnosed among newborns, or self-reported data. To measure the prevalence of selected birth defects among infants of GWVs and nondeployed veterans (NDVs) in Hawaii, using birth defects surveillance records. METHODS: Personal identifiers of 684,645 GWVs and 1,587,102 NDVs and their families were matched against birth certificate records of 99,545 live births reported to the State of Hawaii Department of Health between 1989 and 1993 to identify births to military personnel. These births were matched with records from the Hawaii Birth Defects Program. RESULTS: A total of 17,182 military infants (3,717 GWV infants and 13,465 NDV infants) were identified. Of these, 367 infants (2.14/100 live births) were identified with one or more of 48 major birth defects diagnoses. The prevalence of the 48 birth defects were similar for GWV and NDV infants during the prewar and postwar periods, and among GWV infants who were conceived before and after the Gulf war. CONCLUSIONS: The results must be interpreted with caution because of the small number of affected infants in each birth defects category. This study demonstrated the feasibility of measuring birth defects prevalence among military infants through multiple data linkage. Further, it included live births to parents who had separated from the military, births in civilian hospitals, and birth defects diagnosed through the first year of life.

Epidemiology of neural tube defects, Hawaii, 1986-1997.

Neural tube defects (NTDs) in Hawaii between 1986 and 1997 were examined using data from a statewide birth defects surveillance system. The prevalence increased significantly over the twelve-year period. NTD prevalence did not appear to vary by place of residence. The relationship of type of defect, maternal age, and infant/fetus sex was similar to that reported in the literature.

Prenatal diagnosis and elective termination of neural tube defects in Hawaii, 1986-1997.

OBJECTIVE: To determine the influence of various factors on the prenatal diagnosis and elective termination of neural tube defects (NTDs) in Hawaii in 1986-1997. METHODS: Data from a birth defects registry were analyzed and included 245 cases. RESULTS: 74% of the cases were prenatally diagnosed and 48% were terminated. Anencephaly was more likely to be prenatally diagnosed and electively terminated than spina bifida or encephalocele. Other factors such as maternal age, race/ethnicity, place of residence, and elevated maternal serum alpha-fetoprotein influenced the prenatal diagnosis and/or elective termination of NTD-affected pregnancies. However, a given factor may influence prenatal diagnosis and elective termination in different ways. CONCLUSIONS: Various diagnostic and demographic factors can influence the prenatal diagnosis and the subsequent termination of NTD-affected pregnancies.

Epidemiology of holoprosencephaly in Hawaii, 1986-97.

Holoprosencephaly is a birth defect affecting the medial structures of the brain and face. This investigation examined the epidemiology of holoprosencephaly in Hawaii between 1986 and 1997, using data obtained from a birth defects registry, and compared the results with those of other population-based studies. Twenty-five cases were identified, producing a prevalence of 1.09 per 10,000 livebirths. There were 17 (68.0%) livebirths, two (8.0%) fetal deaths and six (24.0%) elective terminations. Ten (58.8%) of the livebirths died before the age of 1 year. Seven (28.0%) had a known chromosomal abnormality, most often trisomy 13. Prevalence rates were higher for maternal age > 39 years, maternal race/ethnicity of Far East Asian or Filipino, females and residence in Maui County. The small number of cases limited the statistical significance of the study. However, this report confirms many of the findings from the previous studies and adds new findings, particularly the higher prevalence among Far East Asians and Filipinos.

Epidemiology of abdominal wall defects, Hawaii, 1986-1997.

The various types of abdominal wall defects are considered to differ in their etiologies, a hypothesis suggested by differences in their epidemiologies. This study examined the impact of selected demographic factors on abdominal wall defects (omphalocele, gastroschisis, and body stalk anomaly) included in a birth defects registry in Hawaii from 1986-1997. The total prevalence for the various defects were: omphalocele (2.76 per 10,000 births, 95% confidence interval (CI), 2.14-3.50), gastroschisis (3.01, 95% CI, 2. 36-3.77), and body stalk anomalies (0.32, 95% CI, 0.14-0.64). The prevalence increased over the 12-year period for both omphalocele (P = 0.052) and gastroschisis (P = 0.008). Women less than age 20 were at increased risk for a gastroschisis-affected pregnancy, while those age 40 and over were disproportionately more likely to have an omphalocele-affected pregnancy. Pacific Islanders had the lowest risk for omphalocele, whereas Far East Asians were least likely to have gastroschisis. Omphalocele rates were lower outside metropolitan Honolulu, while place of residence did not significantly impact gastroschisis risk. The 1-year survival rate was higher for gastroschisis than for omphalocele (88.5% and 70.7%, respectively), while none of the infants with body stalk anomalies was live-born. The results of this study tend to support the hypothesis of differing etiologies for the studied abdominal wall defects.

Impact of demographic factors on prenatal diagnosis and elective pregnancy termination because of abdominal wall defects, Hawaii, 1986-1997.

OBJECTIVE: The intent of this study was to investigate the impact of various demographic factors on the antenatal diagnosis and elective termination of abdominal wall defect pregnancies. METHOD: Data were obtained from a birth defects registry in Hawaii between 1986 and 1997. RESULTS: The antenatal diagnosis rate was higher for gastroschisis than for omphalocele (76 vs. 60%). However, gastroschisis pregnancies were substantially less frequently electively terminated than omphalocele pregnancies (8 vs. 29%). Factors such as year of diagnosis and delivery, maternal age, race/ethnicity, residence, and maternal serum alpha-fetoprotein screening affected the prenatal diagnosis and/or elective termination of both omphalocele and gastroschisis pregnancies, but frequently in different ways. CONCLUSION: This investigation determined that antenatal diagnosis and elective termination varied with the type of abdominal wall defect and selected demographic factors.

Prenatal diagnosis and elective termination of Down syndrome in a racially mixed population in Hawaii, 1987-1996.

The impact of demographic factors on the prenatal diagnosis and elective termination of Down syndrome in Hawaii between 1987 and 1996 were examined. Data were obtained from a population-based birth defects registry and included 306 Down syndrome cases. 131 (43 per cent) of the cases were prenatally diagnosed. Of the prenatally diagnosed cases, 110(84 per cent) were electively terminated. Advanced maternal age or having a maternal serum alpha-fetoprotein screen performed increased the probability of having an affected pregnancy prenatally diagnosed and electively terminated. Far East Asians were substantially more likely to have an affected pregnancy prenatally diagnosed and electively terminated. Pacific Islanders and Filipinos were less likely to have cases prenatally diagnosed and electively terminated. Prenatally diagnosed and electively terminated Down syndrome cases had disproportionately fewer additional birth defects than live births or fetal demises, suggesting that for many of the electively terminated cases additional birth defects may not have been identified. This implies that the elective termination of Down syndrome-affected pregnancies may influence not only the Down syndrome prevalence but also that of other birth defects.

Trisomies 13 and 18: prenatal diagnosis and epidemiologic studies in Hawaii, 1986-1997.

Using a birth defects registry, this study examined the influence of prenatal diagnosis and elective termination of pregnancy on trisomy 13 and trisomy 18 prevalence in Hawaii between 1986 and 1997. The investigation also evaluated the impact of various demographic factors on risk for the aneuploidies. Forty-seven cases of trisomy 13 and 116 cases of trisomy 18 were identified. The total prevalence of trisomy 13 was 1.91 per 10,000 births and of trisomy 18 was 4.71 per 10,000 births. Elective terminations accounted for 38.3% of trisomy 13 cases and 48.3% of trisomy 13 cases. The 1-year mortality rate for trisomy 13 was 89.5% and for trisomy 18 was 74.3%. Rates for both aneuploidies increased during the time period. The racial/ethnic group with the highest prevalence of both anomalies was Far East Asian. The aneuploidies were more common in metropolitan Honolulu than the rest of Hawaii. Demographic factors demonstrated differences in risk for trisomies 13 and 18, although most of these differences appeared to be due, at least in part, to differences in maternal age distribution. For the secular trend, increased prenatal diagnosis of the anomalies also contributed to the observed increase.

Impact of prenatal diagnosis and elective termination on the prevalence of selected birth defects in Hawaii.

This study examined the effect of prenatal diagnosis and elective termination on the prevalence of neural tube defects, oral clefts, abdominal wall defects, and chromosomal anomalies in Hawaii by using actively ascertained surveillance data collected between 1987 and 1996 by the Hawaii Birth Defects Program. Because the Program has nearly universal access to prenatal diagnostic information and to follow-up data on elective terminations, Hawaii is an ideal setting in which to study their effects on prevalence rates of birth defects. Except for oral clefts, a large proportion of the defects studied were prenatally diagnosed: anencephaly (87%), spina bifida (62%), encephalocele (83%), cleft palate (0%), cleft lip with or without cleft palate (14%), omphalocele (60%), gastroschisis (76%), Down syndrome (43%), trisomy 18 (61 %), and trisomy 13 (40%). The effect of elective terminations on the birth prevalence rates for most of these birth defects was significant. Including electively terminated cases in the calculations of birth prevalence rates increased the rates by more than 50% for five of the 10 birth defects studied.

PIP: A surveillance study was conducted to examine the effects of prenatal diagnosis and elective terminations on the prevalence of neural tube defects (NTDs), oral clefts, abdominal wall defects, and chromosomal anomalies in Hawaii. The analysis involved 10 years of data collected through the Hawaii Birth Defects Program during 1987-96; the data comprised all reported cases of anencephaly, spina bifida, encephalocele, cleft palate, cleft lip with or without cleft palate, omphalocele, gastroschisis, Down syndrome, trisomy 18, and trisomy 13. Findings showed that there were 211 infants with NTDs (87% anencephaly, 62% spina bifida, and 83% encephalocele), 376 infants with oral cleft (14% cleft lip with or without cleft palate), 117 with abdominal wall defects (60% omphalocele and 76% gastroschisis), and 449 chromosomal anomalies (43% Down's syndrome, 61% trisomy 18, and 40% trisomy 13). Prenatal diagnosis and elective pregnancy terminations have a significant impact on the birth prevalence rates of NTDs and chromosomal anomalies. These finding have important implications for other birth defects surveillance programs.

Epidemiology of congenital diaphragmatic hernia, Hawaii, 1987-1996.

Congenital diaphragmatic hernias (CDHs) in Hawaii between 1987 and 1996 were examined with data from a birth defects surveillance system. There were 51 cases of CDH (prevalence 2.45 per 10,000 births). Forty-nine percent of livebirths survived, an increase over the rate reported in Hawaii in 1975-1982. These results are similar to those reported by other population-based studies.

Surveillance for anencephaly and spina bifida and the impact of prenatal diagnosis--United States, 1985-1994.

PROBLEM/CONDITION: The reported prevalence of anencephaly and spina bifida in the United States has steadily declined since the late 1960s. During this time, the ability to diagnose these defects prenatally has progressed rapidly. Many U.S. birth defects surveillance systems ascertain defects only among live-born infants or among infants and fetuses beyond a certain gestational age, thus excluding defects among pregnancies prenatally diagnosed as being affected by a neural tube defect (NTD) and electively terminated before the gestational age limit. The impact of prenatal diagnosis and subsequent pregnancy termination on the reported prevalence of anencephaly and spina bifida in the United States has not been well established. However, assessment of this impact is crucial to the use of surveillance data to monitor trends in the occurrence of NTDs and the effectiveness of interventions for these defects (e.g., increased consumption of folic acid). REPORTING PERIOD: This report presents data from birth defects surveillance systems in six states over different time periods: Arkansas, 1985-1989; California, 1989-1991; Georgia, 1990-1991; Hawaii, 1988-1994; Iowa, 1985-1990; and South Carolina, 1992-1993. DESCRIPTION OF SYSTEMS: Population-based data about a) live-born and stillborn infants with anencephaly and spina bifida and b) pregnancies electively terminated after prenatal diagnosis of these defects were analyzed from the Arkansas Reproductive Health Monitoring System; the California Birth Defects Monitoring Program; CDC's Metropolitan Atlanta Congenital Defects Program; the Iowa Birth Defects Registry, the University of Iowa, and the Iowa Department of Public Health; and the Greenwood Genetic Center in South Carolina. Data also were analyzed from the Hawaii Birth Defects Monitoring Program, which includes data for some women who were not residents of the state. The systems differed in the size and racial/ethnic composition of the populations studied, the surveillance methods used, the completeness of ascertainment, and the availability and utilization of prenatal testing and pregnancy termination. RESULTS AND INTERPRETATION: Among all pregnancies ascertained in which the infant or fetus had anencephaly or spina bifida, the percentages that were electively terminated ranged from 9% in Arkansas to 42% in Atlanta and Hawaii, with a corresponding increase in the adjusted prevalence of these defects compared with the prevalence at birth. In each system, pregnancies associated with anencephaly were terminated more frequently than were those associated with spina bifida. These data indicate that the impact of prenatal diagnosis and subsequent pregnancy termination on the prevalence at birth of anencephaly and spina bifida differs among geographic areas and populations. Comprehensive surveillance for these defects requires inclusion of pregnancies that are prenatally diagnosed and then terminated. ACTIONS TAKEN: CDC will use these data to promote the inclusion of prenatally diagnosed and terminated pregnancies in estimates of the prevalence of anencephaly and spina bifida generated by birth defects surveillance programs in the United States. Including such pregnancies is crucial to the ability of these programs to monitor trends accurately and to establish the effectiveness of interventions, including the use of folic acid, for these defects.