False-rarely does a woman grow a baby that is too big to fit! A much more important factor in having a vaginal birth is the position of the baby. if the babys back is towards moms back, or if babys head is tilted, delivery can be impacted. even small babies can be misaligned! Another important consideration is the position of the mother. labouring women who are active during labour, and assume upright, varied positions, often find labour goes more quickly. trying different positions and avoiding artificial breaking of the waters allows baby to move more easily and get into an optimal position for birth.