Estimation of the number of pregnancies with a neural tube defect (NTD) that would have been prevented if folic acid fortification of flour had been implemented in 1998 in the UK
| Year of notification | Number of pregnancies with an NTD* | Proportion of women taking folic acid before pregnancy (%)† | Estimated additional percentage reduction in women if folic acid fortification implemented from 1998 (%) | Number of pregnancies with an NTD that would have been prevented by folic acid fortification |
|---|---|---|---|---|
| A | B | C=(1−B/100)×23 | AxC | |
| 1998 | 936 | 39.6 | 0‡ | 0 |
| 1999 | 898 | 39.6 | 14 | 125 |
| 2000 | 898 | 39.6 | 14 | 125 |
| 2001 | 884 | 39.6 | 14 | 123 |
| 2002 | 915 | 35.6 | 15 | 136 |
| 2003 | 931 | 35.6 | 15 | 138 |
| 2004 | 910 | 35.6 | 15 | 135 |
| 2005 | 905 | 31.8 | 16 | 142 |
| 2006 | 931 | 31.8 | 16 | 146 |
| 2007 | 875 | 31.8 | 16 | 137 |
| 2008 | 863 | 29.9 | 16 | 139 |
| 2009 | 1019 | 29.9 | 16 | 164 |
| 2010 | 1022 | 29.9 | 16 | 165 |
| 2011 | 1034 | 27.8 | 17 | 172 |
| 2012 | 1012 | 27.8 | 17 | 168 |
| Total (1998–2012) | 2014 |
*From online supplementary appendix table 1.
†From ref. 19.
‡Conservative assumption of no reduction in the first year of fortification.