For most of labor, women feel like an observer instead of a participant. This feeling changes dramatically when the cervix reaches 10 centimeters dilated and 100% effaced. At this point the cervix is said to be “complete” and pushing can begin without fear of causing the cervix to swell or bruise (which can happen if pushing begins BEFORE the cervix is completely dilated or effaced).
The dynamics of pushing can be divided into 3 parts: position, breathing and effort.
Techniques such as pushing while on a toilet, relaxes the perineal muscles while supporting the long bones of the upper legs. Psychologically, moms relax their bottoms when on the toilet and this become important during the Second Stage.
Many mothers will sit at a 30-40 degree angle or C-Position in the birthing bed. Any farther back or even a lying down position will work against gravity and often prolong the pushing part of labor.
Squatting either at the side of the bed or with the aid of a squatting bar encourages rapid descent, requires less physical effort and increases the diameter of the pelvis. Some moms may even do early squat pushing on egg-shaped birth balls. You work with gravity in a squat.
The hands-and-knees position is good for trying to turn a posterior baby, helps with fetal distress and takes the pressure off of the perineum. Many midwives say that this position is the best when there is suspected shoulder dystocia.
During a rapid birth, you may be instructed to side-lie, with your partner or assistant supporting the leg on top. This position slows descent somewhat, lowers the need for episiotomy and helps maintain good oxygen to the baby.
Continuous Breath Holding, also known as purple pushing refers to holding the breath so long and with such force that the small capillaries in the cheeks and face burst. Purple pushing produces Valsalva's Maneuver. Valsalva's Maneuver occurs with prolonged breath-holding ~ longer than 6 clock seconds. With prolonged breath-holding, there is an increase in the heart rate and the blood pressure. Immediately, a reflex of slower heart rate occurs. All of this disrupts the blood flow to the uterus and ultimately to the baby. This disruption in blood flow indicates a disruption in oxygen flow, which ultimately shows up on the fetal heart monitor as fetal distress. There is no clear evidence that closed glottis pushing (Valsalva's Maneuver) shortens second stage, decreases fatigue or minimizes pain. It has otherwise been suggested that bearing down for a prolonged period with a closed glottis alters the effectiveness of the contractions, leading to inefficient contractions and failure to progress.