It can be difficult to be sure about position. I know i get it wrong sometimes and I've been trying hard to get it right for over 20 years! And position can change from ideal to unhelpful DURING labour. Which is very annoying. It happened to me?.
In early labour, where the cervix is not very dilated, its difficult, and uncomfortable for the woman, to feel the landmarks on the head that identify position on VE. And not a lot of point in trying too hard because what you are mainly looking for is whether the labour is progressing. Awkward positions often self correct with good contractions, which might need a syntocinon drip to happen.
there's a bit of a circle that goes on. An awkwardly postioned head, especially in a first labour, can lead to poor stimulation of the cervix, where it doesn't sit in it neatly, like an egg in an eggcup.It might be back to back or it might be sideways where the head is tilted to one side or anterior but not with the chin tucked under. This inhibits the cascade of hormones that should progress the labour. Labour can be slow to start anfd fitful. Contractions are often painful, irregular and do not progress labour. The cervix does not change as expected. The contractions are called "inco-ordinate" ie they happen but they are not effective in the normal way.
Non-invasive methods of dealing with this are; alternately resting and being upright and active; avoiding dehydration and low blood glucose; keeping bladder and bowel empty; pain relief as wanted. The aim is that gravity, varaitions in postion will encourage small changes in position and stronger co-ordinated contractions that will promote progress.
Sometimes, a syntocinon drip is the best option. It encourages the contractions to become co-ordinated, to open the cervix, push the baby down and rotate its head to a more helpful position.
The good news is that this scenario much more often self corrects in a second labour. The uterus "learns" in a first labour (even if it ended in cs or instrumental) and the most likely outcome is a normal vaginal birth without syntocinon.