“Bearing down” is the purposeful muscular effort a person makes during the second stage of labor to push their baby through the birth canal. This voluntary action works in concert with the involuntary contractions of the uterus. It is the final, active push required to move the baby past the fully dilated cervix and out. This effort represents the culmination of the labor process.
The Mechanics of Bearing Down
The physical act of bearing down coordinates several major muscle groups. The primary mechanism involves using the diaphragm and abdominal muscles to increase intra-abdominal pressure. This voluntary force works alongside uterine contractions to exert downward pressure on the baby. The large diaphragm muscle is contracted downward while the abdominal muscles, particularly the rectus abdominis, are tightened.
This combined action simulates the physical strain of having a bowel movement, which is why the sensation is compared to intense rectal pressure. Proper technique directs this pressure deep into the pelvis, toward the rectum and perineum, rather than straining in the chest or throat. Tucking the chin to the chest helps stabilize the body and focus the force downward, maximizing the expulsive power for fetal descent.
Spontaneous Versus Directed Pushing
Two main approaches exist for bearing down: spontaneous and directed pushing. Spontaneous pushing, sometimes called physiologic pushing, relies on the birthing person’s natural, instinctive urge to bear down. The person pushes only when they feel an undeniable urge, typically performing several short pushes during the peak of a contraction. This approach allows for intermittent breathing and is characterized by open-glottis pushing, where air is released during the effort.
Directed pushing, also known as the Valsalva maneuver, is a coached technique. A care provider instructs the person to take a deep breath, hold it for about 10 seconds, and push as hard as possible. This method often results in three to four long, sustained pushes per contraction, regardless of the person’s natural urges. Directed pushing became common practice, especially with the rise of epidural use, which can diminish the natural sensation of the pushing urge.
Timing and Recognizing the Pushing Urge
The pushing stage, or second stage of labor, officially begins when the cervix is fully dilated to 10 centimeters. The physical cue to begin bearing down is not always immediate upon reaching full dilation, however. Readiness is indicated when the baby’s head descends deep enough into the pelvis to trigger the Ferguson reflex. This reflex is caused by the baby’s head pressing on stretch receptors, creating an overwhelming, involuntary sensation.
This urge is described as an intense, unavoidable pressure in the rectum, similar to the feeling of needing a bowel movement. If a person is fully dilated but does not yet feel this strong urge, a period of “laboring down” or delayed pushing is recommended. Pushing before the body or baby is optimally positioned can lead to maternal exhaustion and may cause the cervix to swell, impeding progress.
Physiological Considerations During Pushing
The method and duration of bearing down affect both maternal and fetal well-being. Directed pushing, with its long periods of breath-holding and sustained muscular effort, creates significant physiological changes. The forceful Valsalva maneuver can temporarily reduce the return of blood to the heart, which lowers blood pressure and cardiac output. This reduction in maternal circulation can decrease blood flow and oxygen transfer to the fetus, especially if the push lasts longer than six seconds.
For the mother, prolonged or uncoordinated pushing can increase the risk of exhaustion and contribute to perineal trauma, such as tears. The intense pressure of directed pushing may also increase the risk of nerve and structural damage to the pelvic floor muscles. Spontaneous pushing is associated with a more controlled descent of the baby. This allows the perineal tissues to stretch more gradually and may reduce the likelihood of severe perineal injury.