If you think you are in the active phase of 1
st stage, you should definitely contact the hospital staff (or your caregiver) now, (if you are still at home). Let them know how frequent the contractions are coming and how long they are lasting. There is no need to time every single contraction from the very beginning of the labour, just measure a couple when you notice the labour changing into this phase. This is something your partner or support person can do. You may wish to revise
how to time contractions.
First baby. If this is your first baby, then the active 1st phase is usually the time you would consider moving to your birthplace or calling your midwife to come. The caregiver may ask to speak with the woman directly when you ring. This enables them to listen to the sounds and breathing she is making during a contraction. It also helps them to determine how advanced the labour may be.
Second or subsequent baby. If this is your second or subsequent baby, by rights you should already be at your birthplace, if not get there as soon as possible (unless you're planning a homebirth!)
As the woman, trust your instincts. You usually have an accurate sense of 'when it is time' to call your caregiver, or to leave for the hospital. As the woman's partner or support, have trust in her instincts. Don't try to move her too early (to possibly take the pressure / responsibility off you). Conversely, don't try to keep her at home if she feels too uncomfortable (or nervous) about this. She will only labour well if she is feeling at ease, and in control of the decisions.