I say ‘new’. The CMACE/RCOG advice on folic acid actually came out in 2010, but I can’t be the only one who knew nothing about it?
Basically, the RCOG has suggested that obese women should take 5mg doses of folic acid daily instead of the 400μg advised for ‘normal’ weight women, because obese women have a greater risk of having babies with neural tube defects, and tend to have lower folate levels.
There isn’t actually any evidence yet to suggest that larger doses will work, and there is a study to show that in women with high BMI, taking folic acid supplements did not affect the proportion of babies with neural tube defects, but ho hum.
If you didn’t know anything about it, you’re not alone, a CMACE audit in 2010 showed that only 2.1% of women were taking the recommended dose.
More info here.