This news release touted an observational study that found low-income women in British Columbia who used midwives for prenatal care experienced fewer complications than those who used general practitioners or obstetricians. The study was published in the British Medical Journal Open.
Commendably, the release used mostly cautious language, stating the study adds “new evidence in support of midwives as a safe option.” However, it did not quantify adequately the differences in the outcomes or explain the limitations of observational data.
Midwifery can fill an important need for wider access to care for pregnant women. Advocates for midwives say they reduce unnecessary care, cost less, and lead to great patient satisfaction. Still, news releases should stress the need for ongoing research to assess how the use of midwives affects pregnancy outcomes.
The research report describes the study’s context well, noting that at this stage in the evolution of midwifery care in Canada, a randomized trial could not be supported based on the limited evidence that midwifery care is at least as good as traditional care. Studies such as this one, while not providing a definitive answer, add to our knowledge of the safety of midwifery care and pave the way for further studies that establish its benefits and risks.
There’s no discussion of how much it costs to use midwives in Canada or who pays for their services. The release did note that all of the 57,872 women included in the study had received medical insurance premium assistance.
In general, midwifery care is less costly than that provided by specialists in obstetrics and gynecology and general practitioners.
The study looked at three specific pregnancy outcomes: babies who were small for gestational age, had a low birth weight, or were delivered pre-term.The news release said low-income women who received prenatal care from a midwife had a 29% “lower odds” of a small-for-gestational age birth compared to women who received care from a general practitioner and a 41% “reduction in odds” compared with women who used an obstetrician.
This was insufficient for two reasons.
First, it didn’t provide absolute numbers that would give readers an idea of the size of the difference.
According to the study, 7.09% of all births were small-for-gestational age births. Of those who used midwives, 4.83% had small-for-gestational age births, compared with 7.06% of women who used general practitioners and 8.59% of women who used obstetricians.
Second, the news release did not give any figures about the study’s findings that women who used midwives were less likely to go into early labor or to have a low birth weight baby.
Potential harms of midwifery care could include risks both for the health of the baby, as well as the health of the mother. Maternal health outcomes are not addressed in the study, and not mentioned in the release.
The news release didn’t say anything about the limitations of observational data, which is what this study was based on.
In an observational study, researchers can’t know if they’ve adjusted the data to account for all variables that might have led to differences in outcomes among the three groups. In this study, the authors reported having limited or no data on several factors that might have influenced outcomes: alcohol and substance abuse, mental health conditions, race and ethnicity, language, culture, and the quality of any collaboration between midwives and doctors. Moreover, the study’s author herself notes that “women who are educated and health-conscious typically access midwives early on in their pregnancies.” Thus women who are better educated and more health conscious may have self-selected midwife care, leading to an apparent improvement in outcomes.
With an observational study, unlike a randomized trial, it’s not possible to draw firm cause-and-effect conclusions. In this case, the authors said a causal relationship between midwife care and better outcomes will “need to be established by repeated observational studies with representative samples over time.”
However, a researcher quoted in the news release jumped to a cause-and-effect conclusion, saying the findings “show that women who are more vulnerable benefit from the care of a midwife.”
The news release does not engage in disease-mongering.
The news release did not state how the study was funded, which was through scholarships. It also did not mention that the lead author disclosed in the published study that as of May, she had been providing consulting services to the Midwives Association of BC.
The news release met our threshold here by saying midwives, general practitioners, and obstetricians “are all qualified to provide safe prenatal care for women during their pregnancy, labour and birth, but each offer a different style of care that matches different women’s preferences and needs.”
This was a strong point. The news release noted that midwifery is “not available in all parts of the country.”
“Waitlists for midwives can be quite long, so women who are educated and health-conscious typically access midwives early on in their pregnancies,” said [lead author Daphne] McRae. “But more vulnerable women might not be as aware of the services available to them, so expanding midwifery to make it available for all women is important.”
We like how the news release did not attempt to characterize this study as unique, but rather characterized it as “adding new evidence in support of midwives as a safe option for prenatal care, especially for women who have low socioeconomic status.”
The news release did not use unjustifiable language.