Mama, please check with your OB right away about this, any unusual pain at 38+ weeks needs professional eyes on it, okay? Evening primrose oil at that stage is something your doctor should know about and approve, so best to call them or go to your clinic/hospital para sure. A few of my mum friends consulted their OB before using anything like that kasi they wanted to be 100% safe na, especially na ganitong malapit na ang due date mo. Your baby's safety and yours comes first, always!