If you're trying to get pregnant at 41, you probably don't want to mess around with wondering if prenatal vitamins increase your chances.
Months are precious at this age. If you've been trying for more than a couple months unsuccessfully, both you and your partner probably should go in for a medical evaluation.
Continue and have balance diet as well. Success
In short no prenatal can't help you get pregnant however having a healthy lifestyle can contribute to being more fertile. You should keep taking them and read a book like "Taking Charge of Your Fertility" for some good points on how to get pregnant. The it's really important to keep track of you cycle and have intercourse at the appropriate time