Major congenital malformation risks for antiepileptic drugs comparing monotherapy and polytherapy exposures
| Monotherapy | Polytherapy | |
| % with MCM | % with MCM | |
| Samren 199712 | 8.0 | 9.8 |
| Olafsson 19983 | 3.4 | 8.7 |
| Canger 199913 | 5.7 | 5.3 |
| Kaneko 199914 | 7.8 | 9.6 (2 AEDs), 11.5 (3AEDs), 13.5 (4 AEDs), 15.4 (5 AEDs) |
| Samren 199910 | 3.3 | 4.7 (2 AEDs), 4.4 (3 AEDs), 8 (4+ AEDs) |
| Holmes 200111 | 4.5 | 8.6 |
| Kaaja 200315 | 3.2 | 5.8 (2 AEDs), 8.3 (3+ AEDs) |
| Morrow 200616 | 3.7 | 6.0 |
AEDs, antiepileptic drugs; MCM, major congenital malformation.