Two of my pregnancy yoga mums welcomed their babies to the world this week. One four weeks early, one a week late, but they both said that long, focused, exhales, helped them with their births. So we focused on the Golden Thread breath this week in class.
As a summary :
Relax your jaw / face / shoulders.
Big inhale
As you exhale (slowly), through the nose, have the lips only a tiny bit apart, as though you'd just get a piece of paper in between your lips. Then slowly exhale, visualising a golden thread coming out of your lips, leading you to your baby. The lips are relaxed (not pursed).
Some people prefer to visualise a rope, which is pulling them over the stormy seas of contractions, to your baby.
Whichever visualisation works for you is fine.