Dilation during labor is an important part of the birthing process. As a woman’s cervix dilates, it opens up to allow the baby to pass through the birth canal. There are many factors that can influence how quickly and easily a woman’s cervix dilates. Understanding what helps promote dilation can lead to a smoother labor and delivery.
What is cervical dilation?
During pregnancy, the cervix is normally closed and rigid to keep the baby safely inside the uterus. As a woman goes into labor, the cervix starts to soften, thin out, and open up. This process is known as cervical dilation or cervical effacement.
Full dilation is when the cervix opens to 10 centimeters. This allows enough space for the baby to move through the birth canal and vaginal opening during delivery. Early labor dilation is typically slower, from 0 to 6 centimeters. Active labor speeds things up, from 7 to 10 centimeters.
The timing and progress of dilation varies significantly from woman to woman due to factors like the baby’s size and position. For first-time moms, labor typically lasts an average of 12 to 19 hours. The cervix dilates an average of 1.2 centimeters per hour during active labor.
Why is cervical dilation important?
Cervical dilation is a crucial step for a vaginal delivery. Without enough dilation, the baby cannot descend through the birth canal.
If dilation is too slow, labor may stall out. This can lead to complications like fetal distress or the need for a C-section delivery. Promoting cervical dilation helps labor progress while decreasing the chances of problems.
Tracking cervical dilation during labor helps providers assess how labor is progressing. Interventions can be taken if dilation is not happening at an adequate rate. Monitoring dilation also lets providers offer encouragement during this intense part of labor.
Factors that influence dilation
Many maternal and fetal factors can impact the rate and ease of cervical dilation:
Parity
Parity refers to how many times a woman has given birth. The cervix often dilates faster in multiparous women who have had previous vaginal deliveries. The muscles and tissue have gone through dilation before and may be more pliable.
First-time mothers typically have slower dilation than women who have had multiple vaginal deliveries. However, subsequent deliveries may not always be faster. Factors like the baby’s size can also play a role.
Baby’s station and position
As the baby’s head descends into the pelvis and birth canal, it puts pressure on the cervix. This physical pressure from the descending baby aids with mechanical dilation of the cervix.
If the baby is in an occiput posterior position, with the back of its head against the cervix, there may be less pressure to help dilation along. A challenging position like a breech baby can also impede progress.
Baby’s size
A larger baby usually takes more time to descend through the birth canal. The bigger baby also puts more physical pressure on the cervix to help stimulate dilation.
With a smaller baby, the cervix may not experience as much pressure and stretching to promote efficient dilation during labor. Smaller babies do offer the advantage of moving through the birth canal more easily once fully dilated.
Pelvic size and shape
Some women have a narrow pelvic outlet or an abnormal pelvic shape that provides less room for the baby to pass through. This can slow descent into the birth canal and make cervical dilation more difficult.
A wider pelvis with good anatomical alignment allows an easier delivery that supports cervical dilation. Differences in the shape of the female pelvis account for some variations in the ease of labor between women.
Pelvic floor strength
The pelvic floor muscles support pelvic organs and help hold a baby in place during pregnancy. Toned pelvic floor muscles that have good elasticity may promote more effective dilation.
Weakened pelvic floor muscles that lack elasticity could impede the stretching and opening of the cervix during labor. Kegel exercises are often recommended during pregnancy to strengthen the pelvic floor.
Cervical scar tissue
Previous procedures like cone biopsies, LEEP procedures, or dilation and curettage can sometimes lead to cervical scarring. Scar tissue may make the cervix less pliable and slow the rate of dilation during labor.
However, many women who have had these procedures go on to have normal dilation during labor and delivery. The amount of scarring plays a role in whether it impedes dilation.
Medical inductions
When labor is induced through medical methods, the process of preparing the cervix for dilation happens in a shorter timeframe than with natural labor. This can increase the length of time needed to dilate compared to spontaneous labor.
However,induced labor does not always take longer. Factors like the ripeness of the cervix at the time of induction also play an important role in the rate of dilation.
Emotional support
Having continuous emotional comfort and support during labor has been associated with faster dilation times. The hormones released due to stress and anxiety can sometimes inhibit the labor process.
Relaxation helps promote the release of natural oxytocin, which encourages uterine contractions and cervical changes. The physical effects of tension can also impede labor progress.
Hydration and nutrition
Dehydration and nutritional deficits can contribute to inefficient uterine contractions and slower labor. Good hydration keeps needed oxygen and nutrients flowing to the uterus and cervix.
Eating and drinking as permitted during labor provides energy for the intense work of labor. Dehydration can sometimes manifest as a delay in cervical dilation.
Movement and positioning
Being upright and mobile during labor can promote more effective contractions and descent of the baby into the pelvis. Changing positions frequently may help speed dilation by using gravity to move the baby down.
Lying on the back can restrict circulation to the uterus and cause contractions to be less productive. If dilation stalls, switching positions may help in some cases. Certain positions also widen the pelvic outlet to allow more room for the baby to descend.
Uterine abnormalities
Anatomical variations in the uterus like a septum or bicornuate uterus can sometimes impede cervical dilation. The abnormal shape may provide less room for the baby to drop into the pelvis and birth canal.
However, many women with uterine variations go on to have normal vaginal deliveries. It depends on the degree of abnormality present.
Birth location
Giving birth outside of a hospital typically results in less medical intervention and restrictions on movement. This freedom of movement and lack of disruptive interventions may facilitate a faster, easier labor in some women.
However, access to interventions like induction drugs and epidurals in the hospital can promote dilation in women experiencing slow labor progress. The birth location itself does not directly impact physiology, but the associated practices may play a role.
Interventions to promote dilation
When labor stalls or dilation progresses too slowly, there are a number of options to help move things along:
Rupturing the membranes
If the amniotic sac is still intact, a provider may artificially rupture it to release the amniotic fluid in a process called amniotomy. This may stimulate contractions and descent of the baby.
However, risks like prolapse of the umbilical cord must be ruled out first. Artificially rupturing the membranes also introduces potential for infection.
Uterine massage
Massaging the fundus, which is the top part of the uterus, can encourage stronger contractions. Direct massage of the cervix may help relax the cervical muscles and promote thinning, known as effacement.
This is usually performed by a nurse or midwife trained in the proper technique. Applying hot compresses to the perineum may also provide some relief.
Nipple stimulation
Gentle stimulation of the nipples releases natural oxytocin, the same hormone that causes uterine contractions. The surge of oxytocin can help strengthen contractions to move labor along.
This should be done with care to avoid overstimulation that leads to contractions that are too strong or prolonged. Nipple stimulation is often done when women choose to avoid medicated inductions.
Medications
There are several types of medicinal agents that can be used to help promote cervical ripening and dilation:
– Prostaglandin gel – Applied inside the vagina near the cervix, it helps soften and thin the cervix to ripen it for labor.
– Oxytocin – Given through an IV, it stimulates uterine contractions to enhance dilation. However, it does not work if the cervix is still closed.
– Misoprostol – This prostaglandin tablet also helps ripen the cervix for dilation. It may be used along with oxytocin.
– Cervical ripening balloon – A catheter with a small balloon is inserted through the cervix. The balloon puts pressure on the cervix from inside to encourage dilation.
These medications carry some risks like uterine hyperstimulation, so they must be given carefully under provider supervision. Their use is only appropriate when medically indicated.
Rest and hydration
If maternal exhaustion is inhibiting labor progress, getting rest and hydration may provide the energy needed for labor to pick back up again. Walking around may also help boost energy and descent of the baby.
Taking a short rest to regain strength should not be overlooked. Labor is an endurance event that requires energy.
Operative delivery
If the cervix is not dilating adequately and the baby is showing signs of distress, an emergency C-section may be performed. Operative vaginal delivery with forceps or vacuum may also be an option in some cases.
These procedures bypass the cervix to deliver the baby when vaginal delivery is not feasible or safe. Every effort is usually made to allow labor to progress normally before moving to operative delivery.
When to call the provider
During labor, the cervix should dilate at a steady pace without stalling for too long. Frequent cervical exams track this progress. If dilation slows or stops, notify your provider right away. You should also call if you notice:
– Contractions slowing down or fading away
– Contractions that feel less intense
– Waters break but regular contractions don’t start within a few hours
– Active labor lasting over 24 hours with first delivery or over 12 hours with subsequent deliveries
– Feeling urge to push but cervix is not fully dilated
– Signs of infection like fever, foul odor, uterine tenderness
– Heavy bleeding from the vagina
– Severe abdominal pain between contractions
– Bowel symptoms like urge to move bowels
Your provider can perform an exam to see if any interventions are needed to get dilation back on track. Calling right away provides the best chance for options like induction rather than an emergency C-section.
When to go to the hospital or birthing center
For labor starting outside the hospital setting, the general rule is the “5-1-1” guide:
– Contractions 5 minutes apart
– Contractions lasting 1 minute long
– This pattern continuing for 1 hour
These indicators mean active labor is underway and it’s time to go in for delivery. Heading in sooner could mean being sent back home if not ready yet.
Of course, always go in immediately with any concerning symptoms like bleeding, decreased fetal movement, or fluid loss. It’s best to check in and be evaluated.
Conclusion
Cervical dilation is a critical step in the labor process that allows delivery of the baby through the birth canal. While multiple maternal and fetal factors can influence the ease and timing of dilation, there are tips that may promote a smooth progression:
– Staying mobile and upright during labor
– Changing positions frequently
– Having continuous emotional support
– Staying hydrated with clear fluids
– Using positions that open up the pelvic outlet
– Pushing only as directed while complete dilation is confirmed
If dilation stalls or is too slow, notify your provider promptly so interventions can be considered before problems arise. With adequate dilation, labor can proceed to the pushing stage for a safe vaginal delivery.