Oo naman, possible pa rin mag-pregnant kahit retroverted uterus ka at missionary lang ang position, maraming successful pregnancies with tilted uterus, kaya hindi yan barrier sa conception! The pillow under your bum is actually a smart idea na ginagamit ng maraming moms, helps with angle and gravity din. If concerned ka pa rin after trying for a while, mas better na i-consult mo na with your OB kasi sila na ang makikita ng full picture ng fertility mo overall.