Table 3. . Society of Obstetricians and Gynecologists of Canada Recommendation.

Risk category	Recommendation
Low risk group†	0.4 mg/day: beginning at least 2–3 months before conception, continuing throughout the pregnancy and for 4–6 weeks postpartum or as long as breastfeeding continues
Moderate risk group‡	1.0 mg/day: beginning at least 3 months before conception, continuing until 12 weeks’ gestational age. From 12 weeks, throughout the pregnancy, and for 4-6 weeks postpartum or as long as breastfeeding continues, daily multivitamin supplementation with 0.4–1.0 folic acid is recommended
Increased/high risk group§	4.0 mg/day: beginning at least 3 months before conception, continuing until 12 weeks’ gestational age. From 12 weeks’ gestational age, continuing throughout the pregnancy, and for 4-6 weeks postpartum or as long as breastfeeding continues, daily multivitamin supplementation with 0.4–1.0 folic acid is recommended

Personal positive or family history of other folate-sensitive congenital anomalies (limited to specific anomalies for cardiac, limb, cleft palate, urinary tract, congenital hydrocephaly).

Family history of NTD in a first or second-degree relative. Maternal diabetes (type I or II) with secondary fetal teratogenic risk. Measurement of red blood cell folate levels could be part of the preconception evaluation to determine the multivitamin and folic acid supplementation dose strategy (1.0 mg with RBC folate< 906 and 0.4 to 0.6 mg with RBC folate >906) with a multivitamin).

Teratogenic medications with secondary fetal teratogenic effects by folate inhibition via anticonvulsant medications (carbamazepine, valproic acid, phenytoin, primidone, phenobarbital), metformin, methotrexate, sulfasalazine, triamterene, trimethoprim (as in cotrimoxazole), and cholestyramine.

Maternal GI malabsorption conditions secondary to co-existing medical or surgical conditions that have been shown to result in decreased RBC folate levels (Crohn's or active Celiac disease, gastric bypass surgery, advanced liver disease, kidney dialysis, alcohol overuse).

^†LOW risk group: women or their male partners with no personal or family history of health risks for folic acid sensitive birth defects.

^‡MODERATE risk group: women with the following personal or co-morbidity scenarios (1–5) or their male partner with a personal scenario (1 and 2).

^§INCREASED/HIGH risk group: women or their male partners with a personal NTD history or a previous neural tube defect pregnancy.

Data taken from [17].