Spontaneous labor is best described as the gradual process by which the cervix goes from being a strongly contracted structure that holds the baby within the uterus to a completely relaxed structure that lets the baby out. It is helpful to think of the circular smooth muscles and collagen of the cervix as a tightly bound spool of ribbon, forming a thick, firm base for the uterus. As the longitudinal muscles of the body of the uterus contract, the structure of the cervix relaxes, causing the cervix to slowly thin and open, just as a spool of ribbon unwinds (Figure 5-1).

The melting away of the firm structure of the cervix, until it is flush against the baby’s head, is referred to as effacement and as the cervix both opens and effaces, the baby is able to descend lower and lower into the pelvis. Once the cervix has completely relaxed and retracted behind the baby’s head, the woman uses her abdominal muscles to push the baby down through the lower bony structure of the pelvis and out through the soft tissues of the vagina.

For most women, the first signs of labor are subtle. The baby engages in the pelvis, with increasing sensations of pressure along the pubic bone and lower pelvis. The mother may feel cramping sensations in the upper thighs and lower back pain and shooting vaginal discomfort. The cervix will begin to soften and open, frequently indicated by more significant amounts of vaginal discharge and the passage of the mucus plug, a thick collection of cervical mucus that is yellow or brown in color, occasionally containing small streaks of pink or red blood as well. The gastrointestinal tract may become irritable, as the same hormones that stimulate the uterus stimulate the bowel, resulting in nausea, loose stools, or both. Emotionally, women frequently report a general sense of restlessness.

Uterine activity begins to increase as a woman’s labor process advances. In the early stages of labor, often called latent labor, uterine contractions are mild, short, and irregular. Typically referred to as Braxton Hick’s contractions, many women are not even aware that these contractions are occurring, beyond noticing a periodic tightening of the abdomen. However, once a woman moves toward a more active labor pattern, uterine activity becomes both progressive and persistent, with shorter intervals between contractions, building in both their intensity and duration of the contractions themselves. Once contractions are strong enough and frequent enough to significantly dilate the cervix, most women will find that they need to pause, focus, and breath through the contractions, while in the earlier stages of labor many women are able to continue their daily activities while experiencing contractions. As the cervix further thins and opens, often women will notice mucusy red or brown discharge, referred to as bloody show or birth show.

The latent phase of labor varies greatly in its length, taking only a few hours for some women and lasting days to even weeks for others. It is usually a shorter process for women who have labored in the past, while first-time mothers generally experience a significantly longer period of early labor symptoms before their labor pattern becomes active. Women who experience longer, more symptomatic latent labors frequently express frustration and fatigue with the process and many ultimately elect to have the process medically hastened. However, this gradual process of cervical opening and thinning, referred to as cervical ripening, and fetal descent is important for active labor to proceed in a normal fashion.

This was first examined in the 1960s by Dr. Edward Bishop. He developed a pelvic scoring system, taking into account cervical dilation, effacement, consistency, position, and station, which could be used to predict the likelihood of an induction of labor being successful.¹ While he initially only applied the system to women who had a previous vaginal delivery, more recent studies have replicated his findings in first-time mothers, using a simplified system that only looks at cervical dilation, cervical effacement, and the baby’s station.² These studies have demonstrated that a woman is less likely to have a vaginal delivery if this process of cervical ripening is not complete, whether her labor is induced or begins spontaneously. However, even among women with the least ripe cervixes, a spontaneous labor in an uncomplicated, first-time mother is more than two times more likely to result in a vaginal delivery than an induction, regardless of induction type.³ Fear of ending up in a cesarean section is one of the most common reasons that women cite when indicating why they want to avoid induction.

As discussed previously, induction is incredibly common in the United States, with one in five women being induced. The exact process of induction depends on whether or not a woman’s cervix is ripe at the beginning of the induction. For women with ripe cervixes, most doctors simply start pitocin, which is given intravenously in gradually increasing doses. The amniotic membranes are also routinely ruptured during an induction to aid in the process.

For women without a ripe cervix, the process is more challenging and the preferable method to initiate that process is a subject of frequent study and much debate among medical professionals. Various prostaglandins, physiologically active lipid compounds with hormone-like effects, are used to artificially achieve cervical softening and early dilation, in a process that can take 24 hours or more. These agents can also initiate active labor, but often subsequent pitocin use is necessary to continue active labor progression. The most common agents used in the United States are misoprostol or Cytotec, which can either be administered orally or vaginally, and dinoprostone or Cervidil, which is administered via a vaginal insert. The dosage of Cytotec, unlike Cervidil, is not standardized and studies demonstrating efficacy of Cytotec vary accordingly. However, both Cytotec and Cervidil have been shown to be effective at bringing about delivery within 24 hours, in comparison to pitocin induction alone. Both agents, however, have higher rates of uterine hyperstimulation and meconium fluid, where the baby has a bowel movement while still inside the uterus and can be associated with respiratory distress upon delivery. Cervidil has the benefit of being able to be taken out if too many contractions are noted or the baby does not tolerate the labor. However, Cervidil administered independently as an induction agent is more likely to require subsequent pitocin administration, whereas misoprostol can often achieve full dilation independently. In order to improve the efficacy of both these agents, a balloon dilator may be placed within the cervix to aid in the process by mechanically opening it. Using a balloon dilator can help speed up the ripening process and decrease the incidence of uterine hyperstimulation and meconium fluid, but it does increase maternal discomfort during the induction (Table 5-1)^4,5

The number of medical indications for induction has increased in recent years. Induction is considered medically indicated when it is determined that the risk of continuing the pregnancy is higher to the mother or the baby than the risks associated with induction itself, such as complications of a premature or early term delivery or cesarean section. Some common indications for induction are given in Table 5-2.⁶

In general, the earlier the gestational age, the stronger the risk criteria must be to warrant an induction. Once the 39-week threshold is crossed, induction carries no recognized increased risk to the baby and the indications for induction are significantly more liberal. Some studies even suggest improved neonatal outcomes for induction at 39 weeks when compared to waiting for spontaneous labor up to 42 weeks. The main risk of induction that is considered after this point is the risk of cesarean section however the evidence connecting induction to cesarean is confusing and heavily debated. For patients with a previous vaginal delivery, the risk of a cesarean is small whether they are induced or go into labor on their own, 4.5% versus 2.5%. The main concern about inductions and higher cesarean risk is for first-time mothers, so most of the recent studies focus specifically on this group of patients. The data for many years overwhelmingly cautioned against elective induction in first-time mothers prior to 41 weeks, demonstrating a twofold increased incidence of cesarean in induced patients when compared to those who entered labor spontaneously. However, more recently this evidence has been called into question, as these studies were comparing groups of patients, those that were induced at a certain gestational age and those who went into labor spontaneously at that gestational age, but not really a management decision. Patients cannot choose to go into spontaneous labor at any specific gestational age and thus the decision women and their providers must make is between induction now or waiting until labor begins spontaneously or a medical indication for induction occurs at a later date, when the risk of a cesarean may be higher simply due to larger fetal size and poorer fetal tolerance of the labor process. That decreased tolerance of labor may be due to placental maturation or the complication of pregnancy itself that necessitated the induction. Recent studies comparing women who were electively induced at 39 weeks to women who went into spontaneous labor or had a medical indication for induction at 40 week or beyond demonstrate that the induced groups had similar, or in some studies, lower rates of cesarean than the groups who waited and delivered at later gestational ages.⁷ These newer studies have even led some to suggest that all women should be induced at 39 weeks.⁸ This certainly has not become standard practice and many labor and delivery units actually prohibit elective inductions prior to 40 weeks, but it does raise the question of why women wanting a natural birth are so opposed to induction when it may actually decrease their risk of a cesarean. Are they simply misinformed?

While vaginal delivery rate is the principal outcome that is considered when induction is evaluated by the medical literature, the desire for a physiological start to labor among women wanting an unmedicated birth goes beyond the risk of cesarean section. Virtually all components of a natural birth plan are dependent on a spontaneous labor process. This is because all induction agents carry the risk of uterine hyperstimulation and fetal distress and continuous fetal monitoring is nearly universally recommended whenever pharmacologic agents are being utilized for induction. Continuous fetal monitoring is often problematic for naturally laboring women because it confines a woman to bed positions for labor, unless her hospital utilizes mobile monitors. However, as will be discussed further, continuous monitoring is frequently challenging even with the aid of mobile monitors, so women frequently find their movement restricted even when out-of-bed monitoring options are available. Due to the increased frequency of fetal distress and surgical delivery during inductions, intravenous hydration is commonly prescribed and food and drink are typically restricted or withheld, even if the provider and hospital would otherwise be willing to permit oral intake. The experience of an induction for the mother is also vastly different from a spontaneous labor. Induced labors are significantly longer, increasing the level of maternal fatigue. Higher levels of discomfort are consistently reported in women undergoing induction and, unsurprisingly, the rates of pharmacologic pain relief utilization are increased in response. Even providers supportive of natural birth will often counsel their patients that an unmedicated birth is ill conceived in the setting of an induction. Many feel that because induction is not a natural process, it is nearly impossible to utilize natural methods for coping with the pain of an induction (Table 5-3).

The majority of women intending to naturally birth prefer to only be induced if truly necessary. It is the defining of what is truly necessary that is the subject of so much debate and disagreements among members of the medical community itself and between patients and their providers. For the purposes of this discussion, only the common indications for induction in low-risk pregnancies will be discussed, as high-risk patients desiring unmedicated births are a separate consideration.

Unpleasantly, the usual reason induction is recommended is because of the concern that if the pregnancy were to continue, the risk of loss of the baby in utero would be too great. Thus, to really understand if induction is necessary, parents are forced to contend with the unfortunate and tragic reality that babies can and do die prior to birth. It is a horrific fact that no one wants to think about and can be used to heavily influence a patient who is attempting to avoid a medical induction. Another albeit less significant reason inductions are recommended is to lower the risk of cesarean or development of complications of pregnancy. However, there is a lot of gray in the data surrounding these common indications for induction and ultimately many parents find themselves just agreeing to “the safest thing for the baby,” when in reality they may have been choosing between two safe options for the baby, just depending on how we define safe.

Post Dates

Pregnancies that extend beyond the due date are common, with one in three deliveries in the United States occurring after 40 weeks, according to data analyzed by the CDC.⁹ The number of pregnancies extending beyond 42 weeks, pregnancies that are defined as post term, is approximately 7%. However, in the United States, this rate has been dropping, due both to improved dating of pregnancies with the widespread adoption of early first trimester dating ultrasounds and broader, earlier induction policies, such that only 10% of pregnancies extend to 41 weeks and only 4% extend to 42 weeks.¹⁰ Post dates is the most common indication for induction of labor, accounting for up to one-third of all inductions performed.^11,12

As previously discussed, the risk of stillbirth remains fairly constant throughout pregnancy but begins to slowly increase in the last month of pregnancy until 41 to 42 weeks of gestation, when the rate of loss begins to exponentially rise. The absolute risk of stillbirth through the 42 week is relatively small, however, this exponential rise in poor outcomes continues past the 42-week point and approaches 3 per 100 by 43 weeks, a risk most feel is unacceptable. This is why the 42-week cutoff for induction is so universally applied (Figure 5-2).¹³

The larger debate has been whether induction should be routine at 41 weeks or even earlier, though throughout the United States many practices routinely induce all patients by this gestational age. The reason the 41-week point has become the new cutoff is due to a number of studies that have demonstrated a lower risk of both cesarean and perinatal mortality with this induction threshold. A large randomized trial compared induction at 41 weeks to expectant management up through 44 weeks and found a lower risk of cesarean and higher patient satisfaction with induction.¹⁴ A systematic review that included 22 trials of varied quality involving over 9000 women also demonstrated lower cesarean rates with earlier induction and lower rates of perinatal mortality and meconium aspiration.¹⁵

From this data, induction at 41 weeks seems reasonable and should be considered by women and their providers when pregnancies are prolonged. However, the data certainly does not support mandatory inductions by 41 weeks. Furthermore, there has not been significant study into whether antepartum testing may mitigate some of the risks of going into the 42nd week of pregnancy and beyond, but the current information available suggests this.¹⁰ Antepartum testing is typically performed in the outpatient setting one to two times per week and consists of short durations of electronic fetal heart rate monitoring and/or ultrasounds to evaluate amniotic fluid and other signs of fetal well-being. There also have been newer conflicting studies specifically examining first-time mothers with uncomplicated pregnancies which did show higher rates of cesarean with induction as compared to allowing patients to wait until 42 weeks for spontaneous labor.¹¹ Ultimately, each woman should feel able to decide for herself whether the potential benefits of an induction outweigh the negative impacts induction will have on her labor process.

Prelabor Release of Membranes

Prelabor release of membranes (PROM) is when the amniotic membranes release or waters break before any regular uterine activity or cervical dilation occurs. Water breaking is a common first sign of labor, affecting anywhere from 5% to 10% of pregnancies. Some known risk factors for the development of PROM include maternal yeast and bacterial infections, membrane sweeping, and weekly vaginal exams in the last month of pregnancy.^16–18 It is also a very common indication for induction. The motivation for induction is to prevent maternal and neonatal infection, both of which increase in incidence when the barrier provided by the amniotic membranes is breached for prolonged periods of time, exposing the sterile environment of the uterus to the unsterile, bacteria colonized, environment of the vagina. Most obstetricians perceive rupture of membranes as the starting of the clock on the labor process and aim for delivery within 24 hours.

This perception and the routine recommendation for induction in the setting of PROM is based on early studies in the 1960s and 1970s which showed concerning rates of neonatal infection and mortality of up to 5% when the time from rupture of membranes to delivery exceeded 24 hours.¹⁹ However, these studies were conducted at a time when antibiotics were limited both in terms of their efficacy and application, meaning many women and babies were not appropriately treated when they demonstrated signs of infection and, when they were treated, often those antibiotics were not good at treating the infections present. During this time, there was also no screening or treatment for maternal colonization with group B streptococcal bacteria (GBS), which is a significant risk factor for both maternal infection (chorioamnionitis) and neonatal sepsis and meningitis. Despite these notable differences in infection prevention and treatment, the “24-hour clock” on ruptured membranes has remained a standard part of the obstetrical mindset and labor management.

More recent studies have tried to determine whether routine induction makes sense today, when there is better screening for GBS and better treatment for infection should it occur. A large, randomized trial by Hannah et al. in 1996 compared induction at the time of membrane rupture, using either pitocin or prostaglandins, versus waiting up to 4 days for labor to begin. Interestingly, this study showed no significant difference between the two groups in terms of neonatal infection rates, neonatal mortality, or cesarean section rates. The study did demonstrate, however, an increased rate of maternal infection or chorioamnionitis in the patients who were not induced; however, critics have pointed out that this study did have a relatively liberal definition of maternal infection, possibly over diagnosing infection in the expectant management group. Furthermore, at the time this study was completed, screening and treatment for GBS colonization was still not routinely performed, which could have contributed to the higher rate of infection observed.²⁰ Another more recent observational study of over 6000 women, which included routine screening and treatment of GBS colonization, examined women who were expectantly managed for up to 48 hours rather than induced in the setting of PROM. This study showed low rates of neonatal infection and cesarean in both groups of women, as well as significantly lower rates of maternal infection in the expectantly managed group than in Hannah’s randomized control trial (2.8 vs. 6.7).²¹

The American College of Obstetrics and Gynecology has been flip flopping on their recommendations on PROM for the last 20 years. In 1997, as a result of the Hannah trial, they concluded that either induction or expectant management were reasonable options. However, in 2007, they reversed this position recommending induction on the basis of strong scientific evidence, though the cited sources were no different than in 1997. They repeated this recommendation in 2013, but acknowledged that it was based on limited and inconsistent evidence. Finally in 2017, in the Committee Opinion regarding ways to minimize intervention during labor and birth, they stated that women could be supported in expectant management for 24 to 48 hours, provided no other indication for delivery arose.²²

Interestingly, all the debate over whether to induce actually turns out to be unnecessary for the vast majority of women who find themselves with prelabor rupture of membranes. As was shown in the Hannah trial, when nature is allowed to take its own course, half of women will labor within 5 hours and 95% of women will deliver within 28 hours. Without any evidence to show that induction is necessary from the standpoint of either risks to the baby or maternal risks of cesarean, it would seem all the anxiety and strong armed induction policies are out of place. Women do not “need” to be induced the minute their water breaks; however, they should be counseled about the possible benefits of induction and they may reasonably choose to do so, especially if their hospital has strict policies regarding NICU admission in the event of a maternal fever. They should not be afraid that induction in this setting will increase the risk of a cesarean, but should be aware of the ways in which induction will impact their plans for a natural birth. However, waiting it out is also a safe alternative that doctors and hospitals should support without making women afraid for their infants’ well-being.

Advanced Maternal Age

The average age of women giving birth has risen in the last 50 years. Today, roughly 15% of women giving birth are over 35 and one in five women has their first baby after the age of 35.²³ Women over 35 are known to be at increased risk for a number of pregnancy complications, including gestational diabetes, preeclampsia, chromosomal abnormalities, abnormal placental location and fetal position, and cesarean section.²⁴ They are also at an increased risk of stillbirth when compared to women under 35, with the highest rates observed in women over 40, even when no other complications of pregnancy are present. The cumulative risk of loss from 37 to 41 weeks in older mothers is considerable, occurring in 1 out of 382 women age 35 to 39 and 1 out of 267 women 40 or older.²⁵ Rates of stillbirth in women over 35, as in younger women, have also been shown to increase exponentially in the last weeks of pregnancy, with older women demonstrating higher rates of loss at all gestational ages. However, when recent data is examined, the risk is not nearly as shocking in any given week of gestation and is comparable to younger women at later gestational ages when expectant management is still considered reasonable. For example, from 38 to 40 weeks gestation, the risk of stillbirth in women under 35, between 35 and 40, and over 40 is 0.65/1000, 1.1/1000, and 1.39/1000, respectively. After the due date and extending up to 42 weeks, those rates rise across all age groups, but remain relatively low overall, with a risk of stillbirth of 0.84/1000, 1.91/1000, and 1.61/1000 for women under 35, between 35 and 40, and over 40, respectively.²⁶

Nonetheless, given the overall risk of stillbirth for women of advanced maternal age, several interventional strategies have been proposed and adopted with the aim of reducing the incidence of stillbirth in older mothers. Some of the strategies that have been suggested for women starting at either age 35 or 40 include antepartum testing beginning in last month of pregnancy, with induction or cesarean in those with nonreassuring testing, and/or routine induction somewhere between 39 and 41 weeks gestation.²⁷ However, the only randomized trial to date analyzing the strategy of induction, the 35/39 trial, did not include enough women to accurately assess whether induction reduced stillbirth rates in older mothers. It did demonstrate that there was no difference in the rates of cesarean or other complications of delivery in women over 35 who were induced or expectantly managed until the 42nd week and there were no stillbirths in either group, though only around 600 women were studied.²⁸ While this study did not answer the question of whether women over 35 should be induced to decrease the incidence of stillbirth, it certainly supported the argument that induction is a reasonable option for women of advanced maternal age which does not significantly increase their risk of cesarean. Another observational study comparing approximately 1500 mothers over 35 to approximately 3000 mothers under 35 demonstrated that a strategy of antepartum testing starting at 36 weeks and delivery by 41 weeks resulted in similar rates of stillbirth in both groups of women. While this study type was not sufficient to reliably prove this strategy, it lends support to the argument that the risk of stillbirth in mothers of advanced maternal age can be effectively reduced and provides comfort to those mothers who may desire expectant management and a natural start to labor, at least until 41 weeks of pregnancy.²⁹ To date, neither the American College of Obstetrics and Gynecology nor the Society for Maternal Fetal Medicine recommends either routine antepartum testing or specific induction guidelines for women over 35.

Obesity

Rates of obesity in pregnant mothers, similar to rates of advanced maternal age, are steadily increasing in the United States. Currently, 31.8% of women of reproductive age have a BMI in the obese range.³⁰ Also similar to older mothers, women with elevated BMIs are at increased risk for a number of pregnancy and delivery complications, including diabetes, preeclampsia, cardiac problems, and cesarean. In addition, they are 40% more likely to have a stillbirth than non-obese pregnant mothers, though the absolute risk is still small.³¹ In a large cohort study examining over 2 million women, women with obesity had an overall risk of loss of 3 in 1000 births, with higher rates of loss at all gestational ages when compared to non-obese women and a similar rapid rise in the rate of loss past the 39th week. The highest rates of overall loss and most rapid increases in loss rates in the later weeks of pregnancies were observed in women with the highest BMIs. For example, women with a BMI greater than 50 were observed to have a 5 and 13 fold increase in the rate of stillbirth when compared to non-obese women at 39 and 41 weeks respectively.³² Antepartum testing and early induction have also been proposed as means to reduce risk in this group of patients, however, at this time, there is insufficient evidence that these strategies effectively reduce that risk and are not currently recommended by the American College of Obstetrics and Gynecology. Induction may be particularly problematic in these women, as they are known to have longer labors, greater likelihood of induction failure, and higher rates of cesarean, with increased complications associated with those cesareans, most notably infections.^6,33,34 Ultimately, mothers with elevated BMI, similar to mothers who are over 35 or go past their due date, should be free to consider induction in the context of their own goals and concerns, rather than be pressured into induction, as the current evidence does not show induction has clear benefit and it may have higher costs for these women.

Concern for a Big Baby

Large babies, babies weighing over 8 pounds and 13 ounces, occur in approximately 8% of births within the United States, with only 1.1% of all babies weighing 9 pounds and 15 ounces or more.³⁵ However, two out of three women have an ultrasound near the end of pregnancy to estimate fetal size and one out of three women are told their baby may be too big. Of those women who are suspected of having a big baby, two out of three reported that induction was discussed as a means to prevent the baby from getting bigger and one out of three reported that a scheduled cesarean was suggested.¹² Interestingly, the average size of those suspected big babies was 7 pounds and 13 ounces.

Providers and ultrasounds are similarly bad at predicting which babies will actually be born large for gestational age or macrosomic. A review of 14 studies examining whether ultrasound could predict birth weights found that in most studies, the predictive value of an ultrasound measurement of weight was less than 50%, meaning it was incorrect in the weight estimate as often as it was correct. Ultrasound’s accuracy in predicting very large babies, those weighing more than 9 pounds and 15 ounces was less than 30%.³⁶ Doctors and midwives fare no better at predicting which babies are going to be over 8 pounds and 13 ounces, with those estimates being correct roughly only half the time. In the best-case scenario, an ultrasound is accurate within 1 pound of the actual birth weight, meaning if a baby is estimated to be 8 pounds on ultrasound, it could be as large as 9 pounds or as small as 7 pounds.³⁷ When a woman is told she has a “big baby” based either on a clinical exam or ultrasound, she can basically flip a coin and be as accurate at predicting whether that is true.

However, her provider’s suspicion that she has a big baby can, in and of itself, be a negative thing. Several studies have demonstrated that suspicion of a large baby is associated with higher rates of cesarean, more inductions, and increased labeling of stalled labor. Two interesting studies compared outcomes in mothers who delivered large babies and were suspected to have big babies prior to labor to mothers who also delivered large babies but were not suspected of having a large baby prior to delivery. In the mothers with large babies who were suspected of being so, the rates of induction, cesarean, and maternal complications were significantly higher than those mothers who had surprise big babies, demonstrating that the suspicion of the big baby was more dangerous than the big baby itself.^38,39

Adding to the frustration surrounding this “big baby” obsession is that the interventions that aim to reduce the risks associated with big babies are not significantly effective. The main goal of induction and cesarean with suspected big babies is to reduce the likelihood of a shoulder dystocia, a complication of delivery where the head of the infant delivers, but the shoulder is stuck under the pubic bone, delaying the delivery of the baby and potentially restricting oxygen flow and injuring the nerves to the arm and hand. Shoulder dystocia occurs in 6.7% of deliveries of infants weighing between 8 pounds and 13 ounces and 9 pounds and 15 ounces and occurs in 14.5% of babies weighing 9 pounds and 15 ounces or more at birth.⁴⁰ However, the rate of significant injury, either due to nerve injury or oxygen deprivation, as a result of a shoulder dystocia is less than 1%.⁴¹ While a recent Cochrane Review of four randomized control trials comparing early induction of suspected macrosomic infants with waiting for spontaneous labor did show a small decrease in the incidence of shoulder dystocia among women who were induced early, there were no differences in rates of cesarean or severe maternal or neonatal complications, including shoulder dystocia related nerve injury or oxygen deprivation.⁴² No randomized trials have been performed analyzing cesarean as a preventative strategy, but in an analysis by Rouse and associates, it was estimated that 3695 cesareans for suspected fetal weights of 9 pounds and 15 ounces or greater would have to be performed in order to prevent one shoulder dystocia related nerve injury. Using the 8 pounds and 13 ounces cutoff, 2345 cesareans would have to be performed to prevent one case of nerve injury.⁴⁰ Despite this underwhelming evidence that estimating fetal weights and intervening in response to them makes any sense in low-risk women, these practices are widespread. Some doctors are even mandated by their malpractice insurance providers to perform a CALM shoulder screen, a computerized risk assessment which purportedly can identify mothers at risk for shoulder dystocia though this has not been proven accurate, and counsel their “at-risk” patients about alternative delivery options in response to that supposed risk. The American College of Obstetricians and Gynecologists clearly states in their most recent Committee Opinion that suspected macrosomia is not an indication for induction, but leaves the door open to offering cesarean delivery for babies suspected to weigh 9 pounds and 15 ounces or more.⁴³

It is worth noting that all the studies regarding induction and its impacts on cesarean rates have been conducted within a medically managed model. Many in the natural birth community argue that there is not truly a nonintervention “control” to which induction is being compared, because those in the non-induction groups are likely being restricted to bed, with continuous monitoring, and receiving pitocin for augmentation, having their water broken, and receiving epidurals. Consequently, much of the labor management in the induced groups is similar to the non-induced groups. To really know if induction increases cesarean rates and rates of other complications in all of the situations discussed, women who are induced should be compared to women who are being managed according to a low intervention model, with intermittent monitoring, freedom of movement, continuous hands-on support, oral intake, and access to hydrotherapy. Until then, we are likely only comparing types of apples, not apples and oranges.

One of the most common fears expressed by women prior to childbirth, particularly among women planning an unmedicated birth, is that they will be “strapped to the bed,” unable to move in the ways they wish. Their concerns are not unfounded. In the Listening to Mother’s survey, 76% of mothers reported that they were restricted to bed throughout their labors.⁴⁴ Freedom of movement is a standard request made in any natural birth plan.

There are numerous reasons why unrestricted movement is desirable in labor. Women report less pain, especially less continuous back pain in upright and ambulatory positions. This has been demonstrated in multiple studies of women throughout the first stage of labor.^45–47 Additional studies have also demonstrated less incidence of operative delivery when women are permitted freedom of movement in labor, shortened duration in the time needed to reach complete dilation by 1 hour, less need for pitocin, and less epidural use, with no adverse outcomes observed.⁴⁸ Even in studies where these benefits were not observed, 99% of women randomized to ambulation groups indicated that they would want the option of ambulation in future labors.⁴⁹ An additional benefit of freedom of movement that is not so easily studied, but that women frequently discuss, is an increase in the feeling that they are in control of their labor process, able to move and cope with it in the way their body is telling them to. Furthermore, given the historical context of bed rest, being restricted to bed psychologically conveys the message that one is sick and labor is dangerous, increasing fear and anxiety throughout the labor process which, as shown previously, initiates a hormonal cascade that is counterproductive to the labor process.