Understanding Relative Risks In The Community Birth Setting: An Interview With Researcher Melissa Cheyney
Community birth (planned home and birth center births) has been demonstrated to be a safe option for low-risk women. New research recently published in the journal Birth: Issues in Perinatal Care, entitled Perspectives on risk: Assessment of risk profiles and outcomes among women planning community birth in the United States and authored by Marit L. Bovbjerg PhD MS, Melissa Cheyney PhD, CPM, LDM, Jennifer Brown LM, Kim J. Cox PhD, CNM, and Lawrence Leeman MD, MPH asks the question “safe for whom?”
This research is the first ever look at the relative risks of community birth and based on the largest available dataset in the US on physiologic birth.
Jeanette McCulloch interviewed one of the article’s researchers, Melissa Cheyney PhD, CPM, LDM, to help practitioners and policy makers interpret the findings.
Jeanette: I understand this research is designed to help us clarify how different risk factors impact outcomes for planned community births. Why did you undertake this research?
Melissa: In 2015, I participated in a debate within the British Journal of Obstetrics and Gynaecology where two groups of researchers took sides around the prompt “home birth is unsafe.” Grunebaum, Chervenak and their colleagues wrote a piece arguing that safe planned home birth is clinical fiction. The opposing viewpoint, which I wrote with Marit Bovbjerg and Paul Burcher, questioned, Safe For Whom? We started with the premise that given the larger literature on planned home and birth center births with trained midwives in high-resource countries, home birth clearly can be safe and for some outcomes safer than hospital births for a certain segment of the population. The Dutch, UK, and Canadian studies have clearly shown us this.
But we also know that safety in community birth settings is contingent upon getting some things right, including an essentially healthy client, a well-trained midwife, and a plan for transfer to a higher level of care should a complication arise. Community births are also safest when they occur within an integrated system so that transitions between levels of care are seamless and collaborative.
This caused us to question whether we were asking the right questions. Instead of asking, is home birth safe?, we argued that we should be asking, safe for whom?, under what circumstances?, and using whose definition of safe? This study was born out of a commitment to maternal autonomy and informed, shared decision making.
Since most of our authors are also practitioners who are currently working on the ground with women who are making these choices, we know that when clients are faced with options, they do not necessarily choose what we as practitioners would choose. I think we have all experimented with different methods and strategies for conveying information about risk. What I see happening is that women take information – statistical, numerical, written, verbal, graphic, however we present it to them – and then they filter it through their own value systems and individual histories. What comes out the other side can be quite variable, depending on a client’s religious affiliation, their view of their own body, and their experiences with the medical establishment prior to having this baby. All of these things shape where a pregnant person is going to draw the line for what constitutes acceptable risk.
Many families who consider community birth do not see hospital birth as risk-free, but as an option that carries a different set of risks. They may be negotiating the possibility of having an intervention like cesarean that they did not want or need and then grappling with regret, having to process that in the months and years following their birth. They also understand that having distance between themselves and a hospital means if an emergency does occur, they could be placing themselves at risk. The point is, they do not see one risk-free option. They see two different options with some level of risk associated with each setting. We wanted to be able to provide data that could be used to help inform these kinds of decisions. That was our goal.
Jeanette: The research examines those who are very low-risk in the community birth setting – those who have already given birth vaginally and have no other risk factors – to help us understand how other groups compare. Can you tell us how this research was designed?
Melissa: If you look globally at systems that have integrated maternity care, what you will see is that the definition of “low-risk” varies markedly between systems. There is really no consensus on what constitutes a low-risk client.
What we wanted to do is take some of the exposures (risk factors) that in different systems are considered to put women at higher risk, either based on evidence or based on fears of litigation and ask the question: What are the relative and absolute risks associated with a variety of maternal/fetal characteristics that may render a pregnancy at increased risk for adverse perinatal outcomes within the context of planned, physiologic birth in the community setting?
We started out by really thinking through what those main exposures are. What are some of the things that we often think about as adding risk? We looked at primiparity (having your first baby), multiple pregnancies, breech, gestational diabetes, preeclampsia, postterm pregnancy, which we defined as 42 weeks or greater, older than average women (35 years or older), and women of size, which in the United States we currently define as having a pregravid body mass index of greater than 30. We also looked at having a history of a prior cesarean, because a number of people seeking community care desire to labor after a cesarean, especially in communities where hospital protocols severely limit or fully ban access to vaginal birth after cesarean (VBAC). Next we created a comparison group: multiparous women (those who have already given birth) with no other comorbidities, so a very healthy population. These are the people who would be considered by nearly all providers to be good candidates for community birth. We then compared groups of women with risk factors to the lowest risk comparison group and asked: how do these exposures or risk factors affect some of the key outcomes of maternity care where outcomes included transfers, cesarean sections, hospitalization, NICU admission, and combined fetal and neonatal death rates?
Jeanette: The findings appear to identify three levels of risk, some of which challenge current conventional thinking around what constitutes risk in the community birth setting. Can you tell us about the findings?
Melissa: This is a very complex study, because for every exposure or risk factor, we looked at the risk of several outcomes. We looked at 10 different exposures and 11 different outcomes, so there are hundreds of specific findings in this study. However, what our study showed us more generally is that some exposures are associated with far lower risk than we anticipated, some are about what we thought, and others are higher risk than anticipated.
I would group findings into three categories. Advanced maternal age, multiparous women with a history of cesarean and a history of vaginal birth, and pregravid obesity are the groups at the lowest risk for the adverse outcomes we studied. These risk factors do very little to increase the chance of a negative outcome, including a fetal or neonatal death. Birthing parents with these risk factors, who have been excluded from community birth by some state regulations, may actually be excellent candidates for community birth. That was a surprising finding.
Then there is a middle category where risk is moderately elevated relative to the comparison group. Gestational diabetes that is well-controlled with diet or with oral medications, postdates greater than 42 weeks, primips, and twins all fell into a middle or moderate risk category. It is very important to note here that our sample is biased in that it represents the lowest risk groups within these larger groups as most of the women with complications associated with these conditions (like prematurity in twins or low amniotic fluid levels in postdates), have been referred to a higher level of care prior to the onset of labor. Thus, most of the pregnancies in these groups are at term, well-managed, and for twins, both babies are in vertex positions – so the healthiest of these moderate risk subgroups. Our results then do not apply to all twins, all clients with GDM etc., but just to those for whom these risk factors are well-managed at the onset of labor.
Then there is a third category, which was associated with much higher than anticipated fetal and neonatal mortality and morbidity: women presenting with a breech infant, multiparous women with a history of cesarean but no vaginal birth, and preeclampsia. The breech and preeclampsia findings were not surprising to us, but one of the outcomes we are really grappling with is the risk associated with a labor after cesarean in the community setting when there has been no previous vaginal birth. That is higher risk than we anticipated going into the study.
Jeanette: How should these findings influence the kinds of informed consent conversations that you have as a practitioner when you’re talking with a family?
Melissa: It is important to remember that when you are performing a study like this, you are working with very large numbers. Our study has 47,394 pregnancies. We need large sample sizes in order to have enough power to analyze the differences between groups. However, studies like this can never tell one individual woman what her risk will be or what path she should take, because any one woman can have mitigating or complicating factors that make her lower or higher risk than the category she would be placed in for the purposes of a study.
For example, let’s go back to the finding that labor after cesarean without a prior vaginal birth is associated with greater risk of fetal and neonatal death. We know that within this group, there exists variability. If you have a client who had a cesarean section with her first baby for breech presentation, and now she’s 39 weeks with a favorable cervix, lives close to the hospital, and she has a supportive team of providers who want to enable her to labor after cesarean, the odds of that woman being able to complete a VBAC and do so safely are quite different than someone who had an obstructed labor in their first birth and now has a thick, closed cervix at term with a second pregnancy.
The practitioner will always need to nuance these findings in their discussions with an individual family. Practitioners can begin by giving families a broad sense of the risk landscape. But then the conversation will have to narrow back in, not only to the mother’s individual risk profile, but also to her value system. It is her body, and until the baby is born, she has full autonomy in decision making. She will need to make choices about her care that fit with her worldview and her value system, because she is the one who will live in that body and raise that baby afterwards.
These findings are not directive. They provide tools for a conversation. The same kind of individualized, nuanced care that characterizes the Midwives Model of Care™ will have to continue. However, this research provides far more data than we have ever had before that is specific to the community context to help guide these conversations.
Jeanette: The question of whether or not VBACs at home should be a decision between a provider and a client, or should be in some way regulated by legislation is currently contested in a number of states. How do you think that these findings should influence policy decisions?
Melissa: I think that states need to have general statutes that allow for the practice of community birth in their state. The appropriate state organization or state regulatory body is then obligated to set the rules and regulations for practice. Those rule-making entities and the rules themselves need to be very responsive to the evidence.
When I started in this field in the late ’90s, there were so few articles on outcomes associated with community birth that you could become an expert in the field in a few weeks. Now, the body of literature that is available is staggering, and it is certainly a full-time job to stay on top of it. We need experts in this field to track the literature and to make recommendations every few years about how rules and regulations may need to be modified to reflect the growing body of evidence. This cannot happen adequately when specific practice guidelines are laid out in statute as these can be very difficult and time consuming to change. Evidence based rules require flexibility and nimbleness. We need statutes that enable practice and then regulatory bodies and professional organizations that are responsive to the literature in setting the rules.
I have talked about how this study provides information that can be used for shared decision making, but the other very important thing about what studies like this do is they offer us the opportunity to be self-critical and reflective. They enable us to turn the lens inward and look at our practice as midwives and say, “Where do we need to improve?” This is another place that rules and regulations can play a role. This study is one of two studies that we are working on right now that help us to understand how we can improve outcomes around VBAC. This is something that researchers can work on with educators, professional organizations and regulators. We should be working together to increase access to the safest possible care that continues to honor maternal autonomy.
We can see that there is a very high success rate for vaginal birth after cesarean in our sample, both for women who have had a prior vaginal birth and for those who have not. We can also look at each VBAC case in detail in our registry. Because MANA Stats has so many variables per mother-baby dyad, we can gain a very rich understanding of what is happening in each one of these births.
In this data set we can see approaches to VBAC care that optimize safety and those that may place the pregnancy at greater risk. One example of increased safety is a lower threshold for transfer. This implies some kind of collaborative relationship where midwives and families can make a decision to go to the hospital in a labor after cesarean when labor is not progressing normally. Willingness to transfer early is dependent upon the expectation that families will receive high-quality, respectful care once they arrive. A smooth transfer has a major impact on the outcome of that pregnancy, of that labor. In states where midwives know that a transfer means an automatic cesarean, not surprisingly, families may choose to stay home longer than, in retrospect, is wise or safe.
This kind of work shows us the ways we can shape our practice to improve outcomes. It shows us where there are problems with integration in our maternity care system that we need to work on to improve outcomes for mothers and babies. However, I do not think this kind of work is most effectively done at a statutory level. Our system takes too long to be responsive at that level. Rules, regulations and transfer relationships must be built together through a collaborative community process that is responsive to unique regional, economic and cultural needs.
Jeanette: In other areas of health care in the United States, patient autonomy is recognized as paramount. Why do you think these conversations are more complex when discussing place of birth?
Melissa: I would say part of why this conversation is so hard to have in our country is that we have something that anthropologists call “the home-hospital divide.” There is a gulf between community birth providers and hospital birth providers in many areas. When you have a gulf like that, women are pushed into a position of making an either/or decision. I can birth in the hospital, or I can birth at home. There is a chasm in the middle of this that actually increases risk. I would prefer to see an integrated system where we talk about where a woman starts care and where a woman completes her care.
Any person who begins care with an obstetrician may, at some point, present significant enough complications that they are referred to a perinatologist. That transfer of care is part of a system designed to provide the best possible outcomes for mothers and babies. It is not a failure when women have to move to a higher level of care. I would like to see that same thinking applied to midwifery care and to community birth. A woman should be able to begin care with a community midwife and then collaborate or transfer care as needed. If a risk factor resolves by the onset of labor, then perhaps she can return to the community setting. If not, the midwife could follow her to the hospital as a team member for her birth in the hospital.
We have to get beyond this either/or thinking and realize that there are actually multiple points of collaboration across the entirety of a woman’s pregnancy, birth, and postpartum period where we can be working together.
Jeanette: How should these findings influence how practitioners care for birthing people who fall outside of that very low-risk category?
Melissa: There are three ways that I see these findings influencing practitioners. The first two we’ve discussed already.
First, these findings help us to put information and evidence at the center of discussions around informed, shared decision-making.
Second, they offer an opportunity to identify the specific practices that can improve outcomes in midwifery practice. These findings show that we need to focus our attention on labor after cesarean where there has been no prior vaginal births. We need to ask ourselves, how can we improve outcomes for women who will continue to choose to labor after cesarean in the community environment?
The third thing the findings should inspire us to is collaboration. What these findings show is that while we do not have an integrated maternity care system in the US now, our outcomes are intertwined nonetheless. When you have a region where the only option a woman has for labor after cesarean is in the community setting, this impacts not only families but also midwives, who now carry the responsibility of taking care of a woman who may be at elevated risk. The hospital may also take part in that if a transfer is required.
This study should inspire us to find ways to speak across the divide, to work together to find ways to open the door for all pregnant people to have a full range of options. As they begin to understand their particular risk profile and their own value system around childbirth, clients should be able to have a full range of options before them, and they should be able to move fluidly between each of these levels of care as pregnancy and labor progress, as ongoing risk assessment is a critical part of our model of care.
We need to be asking ourselves why, in a community birth registry, can we find so much data on breech, labor after cesarean, preeclampsia, and GDM? Women are clearly looking for another option that better fits their psychosocial and clinical needs. We need to find ways to respect maternal autonomy and choice while also facilitating the healthiest births possible.