Evening Primrose Oil to induce Labor????

I'm 37 weeks & my first pregnancy experience ended in a 22 hour labor that took pitocin to get her out. Have any of you used evening primrose oil to induce labor? I wouldn't start until I'm 39 weeks cause I hear it thins the cervix which helps for a faster birth. I'm in no hurry to get the pregnancy over, simply want a fast, safe, healthy delivery. If you used it, Did you take it orally or insert the capsule?? If taken orally, did it cause any side effects?