The mhGAP-IG folate dose
This 24-year-old woman has just been diagnosed with epilepsy and started on carbamazepine. The WHO mhGAP Intervention Guide advises folic acid 5 mg a day for all women of childbearing age who have epilepsy, whether or not they are planning a pregnancy. The correct answer is 5 mg daily, the mhGAP-IG recommendation. The advice applies to every woman of childbearing potential with epilepsy, because many pregnancies are unplanned and neural tube closure happens very early, often before a woman knows she is pregnant.
Why folate matters with antiseizure medicines
Several antiseizure medicines, including carbamazepine and valproate, interfere with folate metabolism and are associated with an increased risk of neural tube defects and other birth defects. Folate supplementation before conception and in early pregnancy reduces this risk. Carbamazepine is also an enzyme inducer that lowers the effectiveness of hormonal contraceptives, so she should receive counseling about reliable contraception and about planning any pregnancy with her health worker.
| Dose | Context | Correct for this question? |
|---|
| 0.4 mg | General preconception supplement | No |
| 4 mg | High-risk dose in some other guidelines | No |
| 5 mg | mhGAP-IG: all women of childbearing age with epilepsy | Yes |
| 10 mg | Double the recommended dose | No |
Why the other doses are wrong
0.4 mg is the usual supplement for the general population of women planning pregnancy, not the mhGAP-IG dose for women with epilepsy. 4 mg is a high-risk dose used in some other guidelines, but the stem specifies mhGAP-IG, which fixes the answer at 5 mg. 10 mg is double the recommended dose and is not advised.
Watch out! When a question names a specific guideline, answer according to that guideline even if other sources use a different number. Here the phrase "According to mhGAP-IG" points to 5 mg.
Exam takeaway
Key point! mhGAP-IG advises folic acid 5 mg daily for all women of childbearing age with epilepsy. Combine this with contraception counseling, since carbamazepine reduces the effect of hormonal methods, and with planning for any pregnancy.