Morris J K, Wald N J
Wolfson Institute of Preventive Medicine, Barts and the London Queen Mary's School of Medicine and Dentistry, Charterhouse Square, London EC1M 6BQ, UK.
J Med Screen. 2007;14(2):55-9. doi: 10.1258/096914107781261945.
To determine the prevalence of pregnancies with a neural tube defect (NTD) in England and Wales between 1964 and 2004 and to estimate the relative impact of antenatal screening and a change in the incidence of these defects on the prevalence of births with NTDs.
Use of data published by the Office for National Statistics (ONS) on terminations of pregnancies with an NTD and births with an NTD from 1964 to 2004.
Estimates were made of the total number of terminations of pregnancies and births with an NTD by taking account of the under-reporting of these terminations and births using a previously described method. In 1995 ONS started to report the number of terminations with an NTD rather than the total numbers of terminations with a central nervous system (CNS) malformation that had previously been used to estimate the number of NTD terminations. Adjustment was made for this and new estimates of the total number of NTD pregnancies were produced to 2004.
There were an estimated 969 pregnancies with NTDs (168 (17%) births and 801(83%) terminations) in England and Wales in 2004. An estimated 44% of NTD terminations and 32% of births were not reported as such. The birth prevalence per 1000 decreased fallen 93% from 3.6 in 1964 to 0.3 in 2004, 59% due to an underlying decrease in the prevalence of NTDs and 34% due to screening diagnosis and subsequent termination of affected pregnancies.
The prevalence of NTD pregnancies decreased by around two per 1000 from 1964 to 1990 and thereafter remained fairly constant. The prevalence of NTD pregnancies is substantially underestimated if it is based only on reported NTD births (by 88%) and also if it is based on reported NTD births and terminations (by 52%), because most NTD pregnancies in England and Wales are terminated following antenatal screening and most of these terminations are not reported.
确定1964年至2004年间英格兰和威尔士神经管缺陷（NTD）妊娠的患病率，并评估产前筛查以及这些缺陷发病率的变化对NTD出生患病率的相对影响。
使用英国国家统计局（ONS）公布的1964年至2004年间NTD妊娠终止和NTD出生的数据。
采用先前描述的方法，考虑到这些妊娠终止和出生报告不足的情况，估算NTD妊娠终止和出生的总数。1995年，ONS开始报告NTD妊娠终止的数量，而不是此前用于估算NTD妊娠终止数量的中枢神经系统（CNS）畸形妊娠终止总数。对此进行了调整，并得出了截至2004年NTD妊娠总数的新估算值。
2004年，英格兰和威尔士估计有969例NTD妊娠（168例（17%）为活产，801例（83%）为妊娠终止）。估计44%的NTD妊娠终止和32%的NTD活产未得到此类报告。每1000例活产中的出生患病率从1964年的3.6降至2004年的0.3，下降了93%，其中59%归因于NTD患病率的潜在下降，34%归因于筛查诊断及随后对受影响妊娠的终止。
1964年至1990年，NTD妊娠患病率每1000例下降了约2例，此后基本保持稳定。如果仅基于报告的NTD活产（低估88%）或基于报告的NTD活产和妊娠终止（低估52%）来估算NTD妊娠患病率，会严重低估，因为英格兰和威尔士的大多数NTD妊娠在产前筛查后终止，且这些终止大多未得到报告。
