One of the most common questions among first time mothers is, "When will I know it's time to push?" The most common answer among experienced mothers is, "You'll just know!" The body is designed to begin pushing when pushing will provide assistance at getting the baby out.
When you feel an urge to push may not line up with ten centimeters dilation, although the general medical practice is to prevent pushing until the cervix is dilated to 10 and begin pushing immediately when 10 is reached. This came into practice in an attempt to prevent the cervix from swelling, however it is now known that the cervix is more likely to swell from pushing without an urge than it is from pushing before reaching a specified dilation.
As the baby descends into the birth canal (vagina), the head or other presenting part puts pressure on the rectum. This pressure stimulates the nerves of the rectum which send a signal to bear down and empty the bowels. It feels exactly like having to go to the bathroom.
Sometimes the pressure is overwhelming, and the mother's body pushes involuntarily. You may recognize this by her bearing down, grunting, bracing herself against a sturdy object or by her exclaiming "I have to push!" Other times the urge to push begins mildly, with urges to push only at the peak of the contractions.
If the urge is only at the peak, changing position will either take the urge away, or will allow the baby to slip further into the birth canal and begin strong urges to push. Some women find that simply leaning forward is enough to remove the pressure from gentle urges to push. If the urge to push is not strong, it may be better to change position or lean into the contraction until the pushing urge is strong. This helps to prevent fatigue and allows the strongest pushing to be done when it will be the most effective.
When left alone to push as necessary, most women will do between 3 and 5 pushes that last approximately 6 seconds in one contraction. The variation in length, duration and number of urges in a contraction is due to the position of the baby. Sometimes the baby moves enough with a push that for the next contraction the uterus needs to contract to get tight against the baby again to push on the baby and put pressure on the rectum. Every contraction will have a different pushing pattern.
Some mothers find that they have no urge to push, the baby is simply pushed out by the contractions of the uterus. Most women find that some form of breath holding and contracting of the abdominal muscles similar to a bowel movement feels the most comfortable.
Pushing is done when the baby is outside of the mother. This can take anywhere from 20 minutes to over three hours. After the baby is out, the third stage of labor begins. This is the expulsion of the placenta. It is generally less than 20 minutes and is no more uncomfortable than giving a moderate push when the pelvis feels full.