The changing prevalence of neural tube defects: a population‐based study in the North of England, 1984–96

Abstract

Using data from the Northern Congenital Abnormality Survey, we describe trends in the prevalence of neural tube defects (NTDs), maternal age-specific prevalence, outcome of pregnancy and the sensitivity of antenatal diagnosis of NTD-affected pregnancies in the Northern Region during 1984-96. This population-based sample consisted of 934 NTDs: there were 403 (43.1%) with anencephaly, 472 (50.5%) with spina bifida and 59 (6.3%) with encephalocele. The total prevalence at birth was 17.9 per 10,000 births and terminations (95% confidence interval [CI] = 16.7, 19.0) with a significant reduction over time (chi(2) for trend = 7.2; P = 0.007). The overall birth prevalence was 5.6 per 10,000 births [95% CI = 5.0, 6.3]; there was also a significant reduction in birth prevalence with time (chi(2) for trend = 68.3; P < 0.0001). Maternal age-specific prevalence rates decreased with increasing age. The proportion of NTD pregnancies terminated increased from 60.3% (325 cases) during 1984-90 to 78.6% (293 cases) during 1991-96, whereas the proportion of livebirths declined from 31.7% (171 cases) to 15.0% (56 cases) (P < 0.001). The sensitivity of antenatal diagnosis was consistently high for anencephaly (98%) and increased significantly for spina bifida from 60% during 1984-90 to 85% during 1991-96 (P < 0.05). Ascertainment of all cases of NTD in the Northern Region revealed a twofold reduction in birth prevalence between 1984-90 and 1991-96. This has resulted from improvements in the accuracy of antenatal detection of NTD-affected pregnancies with an increase in terminations of pregnancy.

Incidence of neural tube defects in Afyonkarahisar, Western Turkey

“…In Turkey, the incidence of NTDs is found to be very high when compared even with rates in the British Isles in the 1980s. The spina bifida/anencephaly percentage is low due to an increase of anencephaly cases when the incidence rate of total NTDs is high in the geographical region (Rankin et al, 2000). An inverse relationship between the male preponderance and the incidence of NTDs has also been suggested in different ethnic groups.…”

Registries of cases with neural tube defects in Denizli, Turkey, 2004-2010

“…Encephalocele was found in only 2 cases (0.8%). In a similar study, Rankin et al (2000) reported a total of 984 NTD cases, including 403 (43.1%) cases of anencephaly, 472 (50.5%) spina bifida, and 59 (6.3%) encephalocele. Zlotogora et al (2002) reported 401 NTD cases (167 cases of anencephaly, 167 cases of spina bifida, 48 cases of encephalocele, and 19 cases with other malformations) between the years 1999-2000.…”

“…Environmental factors are well known to affect the etiology of neural tube defects (Rankin et al, 2000). Women who smoked during pregnancy showed a mildly elevated risk [odds ratio (OR) =1.03, 95%CI = 0.80-1.33] of having infants with NTDs (Wang et al, 2014).…”

“…Since then, more than 50 countries worldwide have implemented similar programs (Herrmann and Obeid, 2011). Peri-conceptional use of folic acid in women of child-bearing potential has significantly decreased the incidence of NTD in England and Ireland (Rankin et al, 2000). A study performed in Ontario, Canada found that the prevalence of NTDs decreased from 1.13 to 0.58 per 1000 births in women following fortification with food with an additional 0.2 mg folic acid content (Ray et al, 2002).…”

Prevalencia y Caracterización de los Recién Nacidos con Anomalías Craneofaciales en el Instituto Materno Infantil de Bogotá

“…Se consideran dentro de las anomalías craneofaciales las anencefalias, encefaloceles y otros defectos del sistema nervioso central como la holoprosencefalia, con una prevalencia de 1 a 5 por 1 000 recién nacidos (5,9). Los defectos de primero y segundo arco branquial, incluidas las microtias con una prevalencia de 0,3-5,5 por 10 000 (10,11) y las craneosinostosis con una prevalencia de 0,6 por 1 000 (3,4) también hacen parte de las anomalías craneofaciales.…”