A research letter published recently in the American Journal of Obstetrics and Gynecology argues that the methodology of a recent paper on the safety of planned home births presented a biased analysis.
Dr. Amos Grünebaum
The paper that Amos Grünebaum, MD, and colleagues with the department of obstetrics and gynecology at Lenox Hill Hospital in Hempstead, N.J., referred to is a study in Obstetrics & Gynecology which concluded that planned home births in Washington state are low risk.
In that paper, Elizabeth Nethery, RM, MS, MSM, a midwife and PhD candidate at the University of British Columbia, Vancouver, calculated the outcomes from 2015 to 2020 for “all births attended by members of a statewide midwifery professional association that were within professional association guidelines and met eligibility criteria for planned birth center birth.”
Elizabeth Nethery
Ms. Nethery’s team concluded: “Rates of adverse outcomes for this cohort in a U.S. state with well-established and integrated community midwifery were low overall. Birth outcomes were similar for births planned at home or at a state-licensed, freestanding birth center.”
This news organization was among the publications that reported the results of that study.
But it’s the exclusion criteria in that study, primarily, that Dr. Grünebaum and colleagues take issue with.
Births excluded from the main analysis of the study by Ms. Nethery and coauthors involved “multifetal pregnancy, prior cesarean delivery, onset of labor at more than 42 0/7 weeks of gestation or preterm (less than 37 weeks), preexisting hypertension or diabetes, known amniotic fluid abnormality, gestational hypertension or preeclampsia, or malpresentation.”
Those are conditions that fall outside guidelines for planned home births. But both Ms. Nethery and Dr. Grünebaum said that sometimes these high-risk conditions are present in home births.
Different conclusion for home birth safety
Dr. Grünebaum and colleagues’ analysis of the risk profiles and outcomes for U.S. planned home births for the years 2016-2020 came to a different conclusion about the safety of home births.
They used a retrospective population-based cohort study that used the Centers for Disease Control and Prevention WONDER natality online database. They included planned home births and compared the outcomes with and without certain risk factors, including some high-risk factors such as twin deliveries, breech births, and previous cesarean.
Dr. Grünebaum’s analysis concluded that “it is an immutable truth that planned home births in the United States result in avoidable risks of increased adverse neonatal outcomes.”
Ms. Nethery said though the high-risk conditions were excluded from their main analysis, they are mentioned in the paper and detailed in the supplement.
She acknowledged in the paper that some midwives practice outside the guidelines and that was the case in 7% of births or for 800 people in the Washington state study. But she told this publication it’s a small number and high-risk births should be handled in a hospital so the team focused its research on low-risk births.
“People plan home births who are outside the guidelines everywhere in the world. There are a lot of reasons why people do it,” she said. Among them are not feeling safe in the hospital, being rejected by an obstetrician for a desired procedure, or, in some cases, because they are misinformed.
She said midwives are sometimes faced with a difficult choice, when a patient wants, for instance, a vaginal birth after cesarean (VBAC), one of the conditions not recommended for home births.
The midwife is left with the choice of saying she will not do a VBAC in the home, or she can explain to the patient why it is not recommended and explain all the reasons it is not recommended, such as an elevated risk of rupture, but honor the patient’s choice.
“Do you tell the person: ‘Sorry, go have the cesarean anyway or do you do your best to support this person?’ Birthing people have the right to autonomy of choice,” Ms. Nethery said.
Dr. Grünebaum and colleagues said: “The recent study by Nethery et al. concluded that planned home births in the state of Washington have good neonatal outcomes by focusing on results of low-risk patients.”
Dr. Grünebaum said in an interview: “It’s like reporting on smoking and lung cancer and saying I’m only going to report on patients who have smoked for less than 5 years. You need to take the whole picture into consideration.”
Ms. Nethery gave this explanation for excluding the high-risk patients: “If you are studying a drug, you exclude people from your study who got the drug even though they had risk factors that were ‘contraindications’ to that drug. Likely there was a reason they got the drug – in consultation with their doctor, the patient and the doctor decided that the potential benefit outweighed the risk – but they are not relevant to understanding how that drug impacts people who were ‘eligible’ for the drug in the first place.”
“That is part of the reason we excluded ‘high-risk’ people from our study,” she said. “The other reason is that that is what is commonly done in most research on this topic – we focus on ‘low-risk’ people who are within standards and eligibility criteria.”
She gave examples such as a 2019 meta-analysis and a 2011 Birthplace in England national prospective cohort study, both of which excluded high-risk home births.
“Third, we wanted to compare apples to apples (for our analysis of home vs. hospital) – and licensed birth centers in Washington state have restrictions based on risk,” Ms. Nethery said.
Dr. Grünebaum said his team supports the right of all women to give birth where they wish. “But you cannot choose unless you are given the right information.”
Dr. Grünebaum also said planned home births in the United States cannot be compared with home births delivered by midwives in other countries. Different from the United States, he said, in countries such as Canada, Germany, and England, midwives are well integrated in the medical system and they are typically affiliated with hospitals and they belong to organizations which support very strong guidelines.
He added that, while Washington state has its own set of guidelines, there are no national guidelines for home births and practice varies greatly by state.
The authors concluded: “It is the professional responsibility of all health care providers, obstetricians, and midwives to present unbiased information. Focusing the reporting of outcomes on low-risk deliveries underreports true adverse outcomes in U.S. home births and provides biased information to patients considering planned home births. It is an immutable truth that planned home births in the United States result in avoidable risks of increased adverse neonatal outcomes.”
Dr. Angela Martin
Angela Martin, MD, assistant professor of maternal-fetal medicine and medical director of the labor and delivery department at University of Kansas Medical Center, Kansas City, who was not part of either study, said she did not believe it was a problem that Ms. Nethery’s study excluded the high-risk conditions in the main analysis because it was disclosed.
“The authors were clear that they excluded high-risk conditions,” she said. “Therefore, the study should not be extrapolated to women with these conditions.”
“I believe her results do make that case for low-risk women in Washington state,” Dr. Martin said. “Again, it is important that findings are not extrapolated to women outside of those included in the study.”
She said there are several things that make Washington unusual in midwifery care. Consequently, the results should not be seen as representative of the United States.
“It is one of the most integrated states for midwife care in the country,” Dr. Martin said. “Washington has licensure available for midwives, which is not true of all states. It also has a robust state professional association that publishes guidelines for midwives to follow. And midwives in Washington have a wide formulary. For example, they can administer antibiotics, carry and administer hemorrhage medications, they can carry oxygen, and they are allowed to suture.”
Iris Krishna, MD, MPH, director of perinatal quality, Emory Perinatal Center and assistant professor in the division of maternal-fetal medicine at Emory University, Atlanta, said in an interview that the arguments by Ms. Nethery and Dr. Grünebaum illustrate the controversy over home births.
Dr. Krishna, who was not part of either study, said physicians and midwives should counsel patients contemplating a planned community birth that available data is not generalizable to all birth settings or all patients.
“Women should be counseled that delivery in a hospital setting or accredited birth center is safer than home birth,” she said. “Ultimately, each woman has the right to make a medically informed decision about delivery after adequate counseling on the risks and benefits of community birth.”
Dr. Grünebaum and colleagues reported no relevant financial relationships. Ms. Nethery, Dr. Martin, and Dr. Krishna also reported no relevant financial relationships.