Pathophysiology and prevention
from Section 2 - Fetal disease
Published online by Cambridge University Press: 05 February 2013
Introduction
Neural tube defects (NTDs) are among the most common major congenital abnormalities worldwide, with birth incidence varying between 0.5 and 2 per 1000 births. The incidence is known to vary according to geography and race, with historically higher rates seen in China, Egypt, and India (greater than 8 per 1000 births). Worldwide rates however have been steadily declining. In England the rates peaked between 1954 and 1955 with a substantial decrease seen since, starting in the early 1970s. This decline predated widespread preventative strategies and is unlikely to be explained entirely by prenatal screening. Further reductions have been seen in recent years which have been attributed to the successful preventative strategy of folate supplementation. Current rates are as low as 0.6 per 1000 births in the United States and other countries that have folate food fortification strategies in place.
Open NTDs result from failure of the embryonic process of neural tube closure. This leaves brain or spinal cord neural tissue exposed to the extra-embryonic environment. The spectrum of malformations defined as NTDs include anencephaly, encephalocele, and spina bifida.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.