Table 2.

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.