Adding folic acid to bread-making flour is expected to also decrease the number of miscarriages

It will be compulsory for millers to put the B vitamin in non-organic wheat flour, from mid to late 2023.

The move could prevent up to 240 neural tube defects over 30 years.

The College of Public Health Medicine says as many as 200 miscarriages could also be prevented each year.

Food Safety Minister Ayesha Verrall says it's tricky to quantify the prevention of miscarriages in early pregnancy.

But she'd be very happy to save some families the grief of miscarriage.