Premium
Trends in neural tube defects 1980–1989
Author(s) -
Bower Carol,
Raymond Marque,
Lumley Judith,
Bury Graham
Publication year - 1993
Publication title -
medical journal of australia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 131
eISSN - 1326-5377
pISSN - 0025-729X
DOI - 10.5694/j.1326-5377.1993.tb121690.x
Subject(s) - anencephaly , spina bifida , neural tube , encephalocele , medicine , poisson regression , pregnancy , neural tube defect , population , obstetrics , gestation , pediatrics , demography , surgery , environmental health , biology , embryo , microbiology and biotechnology , genetics , sociology
Objectives To determine trends in prevalence of neural tube defects in Australia over the past decade; to investigate the impact of terminations of pregnancy on the birth prevalence of neural tube defects; and to provide a baseline against which to evaluate the potential effects of preventive public health measures. Data sources Two population‐based registries in Victoria and Western Australia and a statewide survey from Tasmania. Design and method A cohort study. Data on the numbers and the prevalence proportions of neural tube defects from three States — Western Australia, Victoria and Tasmania — were compared by Poisson regression. Results The prevalence proportions for all neural tube defects for all three States remained level over the study period 1980–1989. Terminations of pregnancy for all neural tube defects increased significantly over the decade in all three States. By 1989, 39.9% of all neural tube defects were ascertained as terminations before 20 weeks’ gestation, while 10 years previously only 2.9% were. The percentage of cases of anencephaly ascertained as terminations of pregnancy increased from 4.8% in 1980 to 58.6% in 1989. Corresponding figures for spina bifida were 1.4% (1980) and 26.9% (1989), and for encephalocele 0% (1980) and 12.5% (1989). This increase in terminations was associated with a decrease per year in the birth prevalence proportion for anencephaly of 7.0%, for spina bifida of 4%, and for encephalocele of 11.0%, and a reduction in the risk of a birth with a neural tube defect in 1989 of 47% compared with the risk in 1980. Conclusion Complete ascertainment of all terminations for neural tube defects as well as births with neural tube defects is necessary to provide reliable baseline data on the prevalence of neural tube defects. Such data are essential in evaluating primary preventive measures such as the effect of an increase in folic acid intake by women of child‐bearing age.