15.2: Factors Influencing the Process of Labor and Birth
By the end of this section, you will be able to:
- Discuss the role of the laboring person and fetus in initiating labor
- Explain the signs indicating impending labor
- Describe the five P’s influencing the process of labor and birth
- Analyze the influence of the five P’s on the process of labor and birth
Many factors impact the process of labor for laboring people and the fetus they carry. These factors range from physiology and pathophysiology to psychology and even the environment in which labor occurs. Understanding the expected progression and the factors that can help or hinder the labor process helps nurses provide the quality care necessary to improve outcomes and support physiologic birth .
To remember the crucial factors that influence labor and birth, nurses use the memory aid of the five P’s: power, passage, passenger, position, and psyche. These P’s describe the forces of labor, the pelvic anatomy, the fetal influence on labor, the physical positions involved, and the impact that the mind can have as well. This module will explore each of these as well as additional psychosocial and family factors and note how the nurse can support the process for the laboring person and the passenger they are birthing.
What Is Labor?
The Merriam-Webster online dictionary defines labor as follows: “to exert one’s powers of body or mind especially with painful or strenuous effort” (2023). While this definition is not specific to birth, it is worth noting that labor implies intense physical and emotional work. Nurses are uniquely qualified to support and care for people experiencing the intensity of labor. For the purpose of birth, labor is defined as uterine contractions that lead to dilation and effacement of the cervix and move the presenting fetal part through the pelvis (American College of Obstetricians and Gynecologists [ACOG], 2024). If the pregnant person is not in active labor, the nurse understands the need for providing education and support. The nurse can assist both laboring and nonlaboring persons in coping with their symptoms and providing comfort measures.
Factors in the Initiation of Labor
While the actual mechanisms that initiate labor have proven difficult to identify, it is theorized that the pregnant person, fetus, and placenta each have a part in the process. The initiation of labor includes complex adaptations of multiple systems, including psychologic factors such as perception of safety versus danger (Hundley et al., 2020). Suggested factors originating from the pregnant person include uterine stretch from the growing fetus and amniotic fluid as well as a decrease in circulating progesterone levels and an increase in estrogen levels (Hundley et al., 2020). Progesterone acts on receptors of the uterus to reduce activity, in a sense quieting the uterus. Once this level drops, the uterus becomes primed and ready to respond to oxytocin , which initiates uterine contractions in an intermittent pattern every few minutes until birth and through the postpartum period to prevent hemorrhage. Placental release of corticotropin-releasing hormone (CRH) peaks at term in pregnancy and increases in preterm labor (Hundley et al., 2020). CRH is believed to stimulate the fetal brain to stimulate lung maturity, which in turn helps initiate uterine contractions through increasing cortisol levels and support of the estrogen dominance hormone balance (Hundley et al., 2020).
Signs Indicating Impending Labor
The start of labor can have no signs, or there can be multiple signs that labor is near. Each labor and birthing experience is different, even if the birthing person has given birth before. In 10 percent of pregnancies, the bags of water will break prior to the onset of regular contractions. While this is one way that labor can begin, other ways are much more subtle. These signs can range from uterine cramps consistent with those felt with menses prior to pregnancy, to changes in fetal position or station, and even to the energetic boost colloquially referred to as “nesting.”
When potential signs of labor appear, the nurse’s role is first to identify if labor is present. This can be done by assessing for the presence of uterine contractions. A typical active labor pattern commonly consists of contractions that are strong on palpation, occur every 2 to 3 minutes, and last approximately 60 to 70 seconds. The nurse can also perform a vaginal exam to determine cervical dilation, effacement, and fetal station upon the patient’s arrival and then a recheck approximately 1 to 4 hours later to determine the presence of cervical change. If no cervical change is present within 4 hours, the patient is not currently in labor. The nurse must also identify whether the amniotic sac is ruptured. This is done by a health-care provider or trained nurse, who attempts to identify the presence of amniotic fluid in the vaginal vault or leaking from the cervix (Dayal & Hong, 2023). If a ruptured amniotic sac is ruled out, the nurse can then turn to providing comfort measures and counseling for the patient in the final weeks of pregnancy.
When signs of labor appear prior to spontaneous active labor, the nurse’s role is to first provide reassurance of safety and validation of the person’s experience. Then, the nurse reviews the signs of progression to labor, including the following:
- regular, painful contractions closer together and stronger than the current Braxton Hicks contractions;
- rupture of membranes;
- bloody show;
- nausea and/or vomiting; and deep pelvic pressure (March of Dimes, 2019).
Routine emergency warnings for pregnancy should also be reviewed: vaginal bleeding that saturates a sanitary pad, decreases in fetal movement, fetal kick count under 10 movements within 2 hours, and signs of preeclampsia (headache, epigastric pain, edema in hands and/or feet, or visual changes). Next, comfort measures for the specific symptom should be provided to reduce the discomfort experienced by the laboring person.
Lightening
The process by which the fetal presenting part descends into the maternal pelvis prior to or during labor is called lightening . If the laboring person presents stating that the “baby has dropped” or that they can suddenly “breathe better,” lightening can be confirmed by Leopold’s maneuvers when indicated. Using Leopold’s maneuvers, the nurse identifies if the presenting fetal part has descended into the maternal pelvis and reassures the laboring person that lightening is expected and can be a sign of impending labor, but it can also be the body preparing for the labor process that could still be several weeks away (see Chapter 11 Prenatal Care). A vaginal examination may also be performed to identify the fetal station internally. Fundal height measurements could decrease slightly by 1 to 2 cm from the previous week in the case of lightening. If a more significant decrease is noted, an ultrasound scan may be indicated to assess fetal well-being, growth, and amniotic fluid level (ACOG, 2017a).
When lightening occurs, the nurse takes the opportunity to educate the person on other signs of labor to report or to present to the place of birth for evaluation. Also, the nurse reassures them that lightening on its own is not indicative of current labor but may be a precursor to the other signs of labor. The nurse encourages preparation for labor as well as the promotion of comfort while waiting for labor, whenever it may begin.
Nursing interventions for lightening may include providing comfort with heat or ice, position changes like the hands-and-knees position to relieve pelvic pressure, suggestions for using a pregnancy support belt, and continued suggestions for daily body movement and positions to promote optimal fetal positioning for birth. Suggested body movements for comfort include (Garbelli & Lira, 2021):
- stretching of the psoas muscle by lying on each side with the upper leg draped over the lower leg,
- time in the hands-and-knees or knee-chest position,
- release of pelvic pressure by lifting the abdomen,
- pelvic tilts with or without a birthing ball in each direction for relief of hip pain, and
- gentle walking with an asymmetric gait, encouraging hip movements by one leg stepping higher than the other on a solid surface.
This video from Optimal Maternal Positioning demonstrates the pelvic side-lying release for helping to align the pelvic floor, which can be used during pregnancy or labor.
Braxton Hicks Contractions
Contractions can occur throughout pregnancy, even at very early gestation. They can be palpated as early as 20 weeks’ gestation on the pregnant abdomen. Contractions that occur without cervical change are referred to as Braxton Hicks contractions, named after the physician who first identified them in the literature in the 1800s, Dr. John Braxton Hicks (Young, 1960). These contractions of the uterine muscle fibers are often mild, infrequent, and indistinguishable by the laboring person; but they can be regular, frequent, and painful, depending on the experience reported by the pregnant person. It is common for Braxton Hicks contractions to occur sooner, more often, and with increasing intensity based on the more pregnancies a person has experienced. Increasing frequency and intensity of these contractions can be triggered by low water intake, a full bladder, constipation, physical activity, and sexual intercourse (Raines & Cooper, 2023).
To determine the difference between labor contractions and Braxton Hicks contractions, the nurse should obtain a full history of the presenting symptoms, assess the maternal-fetal vital signs, and perform a focused physical examination. Part of that examination will be a vaginal exam to assess cervical dilation, effacement, and fetal station. If the cervix is not immediately indicative of true labor, then the laboring person and their fetus may be observed for 1 to 4 hours. Reassessment of the laboring person, including the cervix for any change in dilation/effacement/station at that time, would indicate labor has begun. If no cervical change is noted during the observation period, the nurse should include this finding with a complete report of the laboring person’s history and presenting symptoms to the health-care provider. Appropriate follow-up with the health-care provider should be recommended. If cervical change is noted and labor has been identified, the nurse should notify the provider and coordinate nursing interventions for admission and treatment according to provider and facility protocols.
When Braxton Hicks contractions have been identified by the nurse, counseling or patient education is indicated. First, the nurse should reassure the person of safety and validate their experience. Then, the nurse can review the signs of progression to labor with the patient as stated previously. Routine emergency warnings for pregnancy should also be reviewed (see Table 11.9 and Prenatal Care: Part 1). Next, the nurse can provide or teach the patient about comfort measures for relief, including position changes, oral hydration, hydrotherapy, heat or ice application, acetaminophen (Tylenol) use, emptying of the bladder, promotion of bowel health, and rest. All of these can be effective at reducing the intensity or frequency of Braxton Hicks contractions. Finally, the nurse reviews follow-up needs for routine prenatal care and the date and time of the next scheduled appointment.
Mucus Discharge
The cervix is composed of tissue that produces mucus to protect the pregnancy from the extrauterine environment. Prior to the body preparing for labor, the formation of a mucus plug reduces the risk of infection (Weiss, 2022). Throughout pregnancy, the cervix continues to create this mucus, which can be experienced by pregnant people as a notable increase in the amount of normal vaginal discharge. This is referred to as leukorrhea. Leukorrhea of pregnancy should be evaluated because discharge can also be a sign of vaginal infection or leaking of amniotic fluid (Khaskheli et al., 2021). Loss of the mucus plug can take place slowly over time, presenting as leukorrhea, or in one distinct occurrence. The loss of the mucosal plug or a significant portion of it can be alarming to the pregnant person because the plug can be clear to yellow with or without blood within the mucus. When this sudden appearance of mucus occurs, especially when blood is present, pregnant people can experience anxiety leading to a phone call or an emergency department visit. Once labor, infection, and rupture of membranes have been ruled out with the appropriate evaluation and testing, the nurse can reassure the patient that an increase in discharge related to physiologic changes in pregnancy is normal. The nurse then reviews emergency warnings for progression to labor, infection, or rupture of membranes to help the laboring person differentiate the expected mucus discharge from symptoms indicating the need for another evaluation.
Increased Energy
In the third trimester of pregnancy, fatigue is a commonly reported symptom, so when fatigue suddenly resolves or decreases dramatically, this burst of energy can be a sign of impending labor. In some cultures, this energy increase is referred to as nesting. Pregnant people will often report this with excitement, as it is a common symptom in the days or weeks leading to birth. The nurse should appropriately screen for mental health disorders that can present as persistent overactivity; the expected increased energy should be short in duration and combined with appropriate rest and self-care (ACOG, 2018). Once pathology is excluded, the nurse should provide encouragement for the pregnant person and reassurance of normality as well as reminders to stay hydrated and well nourished, and to rest between activities and at night to promote wellness prior to labor.
Cervical Changes
As the body prepares for birth, the cervix can undergo subtle or significant changes in dilation, effacement, position, and consistency. Cervical dilation prior to labor can be subtle, with just slight progression from a closed cervix to one that is 1 or 2 cm dilated. However, it is also possible to see advanced dilation of 6 cm with no signs of labor. Cervical effacement can also be subtle, with only 20 percent to 50 percent of effacement beginning prior to labor, but it is possible to encounter a paper-thin, 100 percent effaced cervical os that can be difficult to differentiate from the rest of the lower uterine segment. The cervix is typically posterior when the body is not in labor but can move to mid position or even an anterior position in the weeks, days, or hours leading to birth. Consistency of the cervix can also be a sign of impending labor; the texture of the cervix softens to allow it to be more responsive to the contractions in labor (Burch, 2022). Of note, these changes can occur sooner and more significantly with pregnant people who have had previous vaginal deliveries. The nurse should rule out labor by assessing for cervical change under the influence of contractions.
Evaluating Labor
A nurse evaluated a gravida 2 para 1 pregnant person at 39 weeks’ gestation who presented with a report of regular, painful contractions every 5 minutes, each lasting 1 minute, for 1 hour. The initial cervical exam was 4 cm dilation, 50 percent effaced, at –2 station. After monitoring for 20 minutes, the nurse noted contractions to be occurring every 5 minutes with a Category 1 fetal heart rate (FHR) pattern. Monitoring was discontinued, and the patient was assisted to ambulate or reposition for 2 hours, with fetal heart tones obtained every 30 minutes via intermittent auscultation. FHR was 130 to 140, and no decelerations were noted during the intermittent auscultation. At the end of the monitoring period, the cervical exam remained unchanged. At that time, the nurse reported the patient’s unchanged status to the provider and was instructed to discharge the patient home with labor precautions and to follow up in the office if labor did not begin by the regularly scheduled prenatal visit later that week. The patient called 4 hours later, reporting that they had just birthed their baby at home unassisted. The newborn was audibly crying vigorously. The nurse instructed the patient to call 911 for emergency assistance and transport to the nearest facility for continued care. Consider whether the care team is ethically or legally liable for this event.
The pregnant person was evaluated for cervical change. When no cervical change was noted, the pregnant person was determined to not be in active labor and was discharged home in stable condition. Did the care team provide evidence-based care? Did the nurse follow all policies and procedures and provide adequate documentation?
Rupture of the Membranes
Rupture of membranes (ROM) occurs when the two layers of the amniotic sac have openings that result in leaking of the amniotic fluid through the vaginal opening that is noticeable by the laboring person. ROM can occur spontaneously prior to the onset of labor, during labor, or as an intervention when the labor is induced or augmented. Without intervention, most laboring people will experience spontaneous rupture of membranes (SROM) during active labor or during second stage labor; however, in a small subset of people, birth can occur with intact membranes in what is referred to as an “en caul” birth.
To identify rupture of membranes, nurses can use visual inspection of any sanitary napkins or absorbent materials brought in by the laboring person. The nurse can complete a digital vaginal examination, obtain commercially available diagnostic tests for amniotic fluid (Table 15.1), or assist with sterile speculum exams to identify pooling in the posterior fornix. Samples of fluid can be assessed using nitrazine paper to determine pH and/or microscopic examination revealing a distinct ferning pattern (shown in Figure 15.2). Of note, nurses can complete specific training to be certified to perform sterile speculum exams in obstetric and gynecologic settings.
| Test Name | Accuracy of Test |
|---|---|
| Amnisure | 95.7% sensitivity, 92.3% specificity |
| ROM Plus | 99% sensitivity, 91% specificity |
| Nitrazine | 78.1% sensitivity, 97.8% specificity |
Beliefs Surrounding the Amniotic Sac
Many cultures across the world believe that newborns born inside (en) or covered by a portion of the amniotic sac (caul) are special due to how rarely these births occur. This belief is thought to date as far back as Roman times or before in some Asian cultures and has remained strong, especially in Southern states among Black Americans (Rich, 1976). Some people believe babies born en caul are lucky and have supernatural powers (Ronca, 2021). Today, intentional en caul births for extremely preterm infants are being utilized in Japan (Murakoshi, 2020) to reduce pressure-related trauma to the fragile preterm patient and prevent vertical incisions on the uterus common with cesarean deliveries of extremely low birth weight fetuses.
Factors Influencing Labor and Birth
The five P’s—power, passage, passenger, position, and psyche—are a way to remember the components that make up the physiology of birth. The strength of the uterine muscle contractions and the birthing person’s expulsive efforts is power . The pelvic anatomy that the fetus navigates during birth is passage . The fetus and how they proceed through the passage is considered passenger . The position of the laboring and birthing person impacts much of the birth process and is often a very simple way to change the course of labor. Finally, the psyche , or mind, of the laboring and birthing person can have a lasting impact on every stage of labor and birth. Each of these is discussed in greater detail in the sections that follow.
Power
Birth is one of the most intense experiences the human body can endure. That intensity is fueled by the power of the muscles and the effort expended in labor and birth. It is important to note that while medications and anesthesia can reduce the perception and sensation of pain during the experience, the bodily acts of labor and birth are still physically demanding. As such, the nurse needs to closely monitor the process and support the health and wellness of the laboring person and their passenger.
Contractions
The myometrium of the uterus is made of smooth muscle fibers that contract when stimulated, causing downward pressure on the fetus. The fetus subsequently applies pressure to the cervix, leading to cervical effacement, dilation, and changes in fetal station when contractions are persistent and strong. Figure 15.3 illustrates how effacement, dilation, and fetal station are measured. The muscle fibers of the uterus also progressively retract as the muscle contraction subsides to reduce the length of the fibers and prevent the fetus from rising all the way back to the original position prior to the contraction. This coordinated contraction and release of the muscle fibers with retraction during the release makes up the contractions in labor and birth (McEvoy & Sabir, 2022). These progressive muscle contractions across the uterus are the power behind the first stage of labor. Contractions occur in a wave-like formation, beginning with less intensity, building to more intensity, and then returning to the resting tone of the muscle fibers between the contractions. Nurses assess the frequency, intensity, and duration of contractions, as shown in Figure 15.4. Patterns emerge in the stages of birth that relate to the other four P’s; these patterns can be a guide for how to adjust an abnormal labor.
Pushing Effort of the Person in Labor
The power of labor also refers to the second stage of labor when the birthing person begins expulsive efforts to move the fetus through the pelvis and pelvic floor. Pushing efforts are often referred to as effective or ineffective based on the fetal station progress in relation to the maternal pelvis (Huang, 2019). The power of pushing can be affected by muscular strength and coordination, epidural anesthesia causing decreased sensation of the urge to push, fetal positioning that is optimal or suboptimal for vaginal birth, and the strength of the uterine contractions supporting the birthing person in their efforts to deliver their passenger.
Passage
The passage, or way through which birth occurs with labor, includes the pelvic structures of bone and soft tissue. Relaxin, one of the hormones that prepare the body for birth, softens the ligaments of the pelvis, causing a shift in the pelvic floor anatomy to accommodate the changes in diameter needed for birth. The passage can be affected by the laboring person’s mobility in pregnancy and labor, perineal massage prior to birth, pelvic floor health, pelvic anatomy diameters, and in rare cases health conditions that affect those diameters.
Pelvis Shape
Traditionally, the pelvic diameters and overall shape were categorized into four different pelvis shapes: gynecoid, android, anthropoid, and platypelloid, which were determined by clinical pelvimetry or by measuring of the pelvic structures digitally during a vaginal exam. However, growing evidence suggests that these categories are entrenched in racial bias and are of little importance in relation to birth outcomes (VanSickle et al., 2022). Traditionally, the gynecoid pelvis was the preferred pelvic shape because the circular inlet was the most favorable for occipital anterior fetal position for delivery, with less likelihood of prolonged or complicated labors. Anthropoid pelvis shapes are associated with a long oval inlet, which is more often associated with occipital posterior deliveries that can have more complications and interventions. Platypelloid pelvis shapes are associated with a short oval inlet and a transverse facing fetal head for birth, which is associated with more complex labors with increased interventions. Android, or the male pelvis shape, has a heart-shaped inlet that is associated with arrest of labor deep in the pelvis. The issue with these different shapes is that evidence has not shown that they are independently predictive of positive or negative birth outcomes. This was consistent in the most recent Cochrane review of pelvimetry that found no improved outcomes with the use of pelvimetry versus no use of pelvimetry and an increased risk for cesarean section in those exposed to pelvimetry (Pattinson et al., 2017). Figure 15.5 illustrates pelvis shapes; some practitioners still use these terms, but the nurse should understand the limited value of the pelvic characteristics.
Soft Tissue
The pelvic floor supports the abdominal cavity throughout the lifespan of all humans, but during birth it becomes much more dynamic and serves a crucial function in vaginal delivery. The major muscles and fascia provide resistance for fetal rotation and descent within the pelvis. Alterations in function can occur when the pelvic floor has too much or too little support for the movement of the fetus through the passage. For laboring people with previous pelvic floor damage or multiple births, weakness of the muscles can allow for malposition leading to dysfunctional labor. For laboring people with increased resistance of the pelvic floor due to a trauma history, overcorrection of muscles after previous pelvic floor damage, or strenuous exercise, increased resistance can lead to dysfunctional labor as well (Gachon et al., 2020). The goal with the pelvic floor is to provide adequate support while also allowing for stretching over the fetal presenting part to allow passage for birth.
Passenger
While labor is often focused on the experience of the laboring person, it is crucial to understand the fetal factors that affect labor. The fetus can impact labor significantly, depending on the fetal tolerance to the powers and passage as well as the fetal size and position within the pelvis. The fetus is physiologically designed to pass through the vaginal tissues and pelvic diameters, often following specific patterns of progression that can lead to changes in the labor process experienced by both the fetus and the laboring person.
Fetal Head
The cranial bones of the fetus have sutures that are not yet fused and fontanelles that compress to allow for significant alteration in shape (Figure 15.6. Compression of the cranial bones, sutures, and fontanelles to allow for the fetus to pass through the birthing person’s pelvis is called molding . It allows the skull to accommodate the pelvic diameters of the inlet, the midpelvis, and the outlet. The diameter of the fetal skull along with its ability to pass through the pelvic anatomy is significantly affected by the presence of molding as well as fetal lie, attitude, and position, which are reviewed in the following sections.
Fetal Lie
The fetal lie refers to the relationship of the fetal long axis, or spine, to the maternal long axis. Fortunately, greater than 95 percent of fetuses present in a longitudinal lie at term. A non-longitudinal lie is more common with preterm gestation, grand multiparity, abdominal wall laxity, uterine anomalies, or the presence of uterine fibroids. See Chapter 11 Prenatal Care for more discussion of fetal lie.
The transverse lie describes a fetus with the long axis perpendicular to the maternal long axis. When a fetus is in the transverse lie, the fetal spine is further described to be in the back-down or back-up orientation. Transverse lie at term is not compatible with vaginal birth and indicates the need for a change in fetal position or ultimately a cesarean birth (Ghi & Dall’Asta, 2024). The oblique lie describes a fetus with the long axis at an angle between the perpendicular and parallel. Fetuses with this lie are often further described by the location of the presenting part in relation to the maternal abdominal quadrants—for example, fetal head in left lower quadrant. An oblique lie will often convert to a longitudinal lie with the increased intrauterine pressure caused by contractions in active labor, but this lie can be associated with abnormal labor progress due to lack of pressure on the cervix by the presenting part. See Figure 11.6 for illustrations of fetal lie.
An external cephalic version (ECV) can be offered in an attempt to change the fetal position and, if successful, can negate the need for a cesarean birth. An ECV is a procedure in which the fetus is manipulated through the external abdominal wall in an attempt to move the fetus into a cephalic presentation; this procedure is 58 percent successful (Shanahan et al., 2023). The health-care provider discusses the risks and benefits with the pregnant person, and a decision is made whether to proceed with the ECV. The risks include fetal heart rate bradycardia or other transient abnormalities, rupture of membranes, vaginal bleeding, cord prolapse, placental abruption, stillbirth, and emergency cesarean section (Shanahan et al., 2023). The provider will explain that ECVs are more successful in multipara persons, when the presenting part is unengaged, with a posterior placenta and normal amniotic fluid amount (Shanahan et al,, 2023). An ECV is contraindicated in those with a history of a vertical cesarean scar, multiples, too little amniotic fluid (oligohydramnios), uterine or fetal anomalies, nonreassuring fetal heart rate, or fetal growth restriction (Shanahan et al., 2023). After consent is signed, the nurse will administer terbutaline, nifedipine, or call for an epidural placement to relax the uterus, depending on the order from the health-care provider. The procedure will include monitoring of the fetus via an ultrasound or Doppler scan. The nurse prepares for a possible emergency cesarean birth by having the operating room ready and ensuring that staff are available for the cesarean. After the uterus is relaxed, the health-care provider or providers will attempt to lift the presenting part of the fetus and rotate the fetus to the cephalic position. If successful, the person is a candidate for a vaginal birth; if not, the person will be scheduled for a cesarean birth. Figure 15.7 illustrates the procedure.
Fetal Attitude
The fetal attitude is the presence of flexion or extension (also referred to as deflexed) of the fetal head and neck. In most labors at term, the fetus presents with a flexed head and neck to decrease the diameter of the fetal head to conform to the maternal pelvis. This is also known as the vertex presenting. When the fetal head is extended, the fetus is described as brow or face presenting. Face presentation requires a completely deflexed or extended head to enter the pelvic inlet (Ghi & Dall’Asta, 2024). A variety of fetal attitudes are shown in Figure 15.8.
Fetal Presentation
The fetal presentation is the part of the fetus that occupies the lower part of the uterus, also referred to as the presenting part. The fetal presentation can be determined by Leopold’s maneuvers or during a vaginal exam. Cephalic presentation describes the fetal head being the closest fetal part to the maternal pelvis (see Figure 15.8). Breech refers to the fetal buttocks or lower extremities presenting closest to the maternal pelvis. Breech fetuses are of several types, including frank breech, complete breech, incomplete breech, and footling breech (Figure 15.9).
Fetal Position
The fetal position is the relation of the presenting fetal part to the pelvic anatomic landmarks (Figure 15.10). Using Leopold’s maneuvers and internal vaginal exam, the nurse should attempt to identify the fetal position. Via Leopold’s maneuvers, the nurse identifies fetal lie, fetal presentation, and where the fetal back is lying, and assesses the attitude to predict the position that will be noted in the vaginal exam (face/brow/vertex). During the internal exam, the nurse digitally examines the fetal presenting part for identifying features to map the position in relation to the maternal pelvis.
For the vertex fetus, the identifying features are the sagittal suture, anterior fontanelle, and posterior fontanelle. First, the nurse identifies the sagittal suture and determines the orientation. Is it anterior-posterior, oblique, or transverse in relation to the maternal pelvis? Next, the nurse follows the sagittal suture bilaterally to identify the fontanelles. The posterior fontanelle is often compressed when labor has progressed enough to palpate the fontanelles and presents as a Y-shaped depression with three sutures approximated or overlapping. The anterior fontanelle is not compressed and will be palpated as a diamond-shaped depression with four sutures lining the fontanelle. The occiput, where the posterior fontanelle is noted, is the denominator for describing the fetal position in a vertex fetus. It can also be helpful to determine if the sagittal suture is midline (synclitic position), toward the sacral promontory (anterior asynclitic position), or the pubic arch (posterior asynclitic position) because asynclitic positions can increase the risk of abnormal labor patterns.
Fetal position is the most difficult aspect of the passenger to accurately identify. In 2020 one study found that the sensitivity of Leopold’s maneuvers is reassuring at 93.2 percent but the specificity was very low at 30 percent (Udompornthanakij et al, 2020). Due to the high rate of inaccurate identification, the nurse should understand that if the interventions to assist with the presumed malposition or desired position are not effective, reassessment or a trial of alternative interventions is reasonable. This skill can be developed with practice, and many OB/GYN nurses and providers can increase their accuracy in this skill when they combine it with ultrasound confirmation (Udompornthanakij et al, 2020).
For presentations other than cephalic, the denominator when describing position is:
- breech: fetal sacrum
- face: fetal mentum
- shoulder: acromion
Position of the Birthing Person during Labor and Birth
When nurses consider the birth process, it is important to recognize that labor is a dynamic progression that requires many shifts and changes by the maternal pelvis and especially the fetus. The easiest way to promote the normal physiologic progression of labor is to encourage an upright position when laboring and movement and position changes for the laboring person. By repositioning the laboring person, the fetal position will often shift as well. This continued movement encourages the internal rotational maneuvers necessary for the fetus to progress through the pelvis to complete the birth process. Because of this, when a slow labor or fetal heart rate change occurs, the nurse should think, “What position is the patient in?” followed closely by “What position should I try next?”
There are many proposed positions for each stage of labor with accompanying reasons why each is recommended. The nurse must remember that movement, especially upright movement, is the most crucial factor in supporting normal, or intervening in abnormal, labor (Garbelli & Lira, 2021). Many cultures have deep-rooted norms in birth that can be as specific as which position the birthing person assumes the moment their baby is born. In many cultures, upright birth is depicted in ancient art and built into modern health-care systems. In the United States, the norm has become the lithotomy position, but a growing body of evidence suggests this position may actually cause harm to the birthing person through increased risk of pelvic floor dysfunction or injury. This position may also harm the fetus through increased stress during the second stage (Huang et al., 2019).
Nurses must be sure to protect the body mechanics of the patient, especially when epidural anesthesia is in use. There have been reports of musculoskeletal and nerve injuries from prolonged use of single positions, especially those with significant hip flexion like lithotomy. The nurse should consider frequent position changes to left and right side-lying position, squatting, hands-and-knees position, high Fowler’s position with asymmetric legs supported on a peanut shaped birth ball, closed-knee positions for outlet opening with low station, or even supported upright positions with epidurals that allow for lower body movement. Nurses also need to assess their own body mechanics when supporting patients in labor. Some hospitals have created policies that do not allow nurses to lift a patient’s legs when in lithotomy positions due to the risk for staff injury.
Psyche of the Birthing Person during Labor and Birth
The hormones of birth function optimally in comfortable, low-stimulation environments that avoid stress, anxiety, fear, and negativity (Bellini et al., 2023). To support the positive psyche of the laboring person, the nurse should assist them in creating their most comfortable environment. The same way many people prepare for sleep is often the best support for the patient’s psyche in physiologic birth . Consider a quiet, dark room, with only soft lighting, if any, present; introduce pleasant smells, peaceful music, or white noise if silence is not preferred or possible; and surround the birthing person with personal comfort items, including soft fabrics for bedding or clothing. Most birthing facilities are not designed with this purpose in mind, but some nurses have become experts at transforming the environment to support the physiology of labor. Many labor units now offer alternative lighting, face masks, black-out curtains or shades, diffusers with essential oils like lavender to promote calm and pleasant aromas, noise-reducing panels, alternative labor gowns, sound systems where patients can play their own music, and reduced visitor restrictions to allow for support teams that patients want and need.
This video animation depicts the coordination of uterine contractions, pushing, and fetal movements that work together to birth the fetus.