After giving birth, most mammals eat the afterbirth, the placenta. Most humans don’t. Several hypotheses have been suggested as to why placentophagy might have had evolutionary survival value, but are there any actual benefits for modern women? Placentophagy has been recommended for various reasons, from nutritional benefit to preventing postpartum depression to “honoring the placenta.” In other cultures, various rituals surround the placenta including burial and treating it as sacred or as another child with its own spirit. Eating the placenta is promoted by some modern New Age, holistic, and “natural-is-good” cultural beliefs.
Some women eat it raw, but many women have a yuck-factor objection to eating raw bloody tissue. It can be cooked: recipes are available for preparing it in various ways. For those who don’t like the idea of eating the tissue, placenta encapsulation services are available, putting placenta into a capsule that is more esthetically acceptable and that can even be frozen and saved for later use in menopause.
Does placentophagia benefit health? Does it constitute cannibalism? It it just a way to recycle nutrients? How can science inform our thinking about this practice? (more…)
A new article in the Journal of Women’s Health by Westhoff, Jones, and Guiahi asks “Do New Guidelines and Technology Make the Routine Pelvic Examination Obsolete?”
The pelvic exam consists of two main components: the insertion of a speculum to visualize the cervix and the bimanual exam where the practitioner inserts two fingers into the vagina and puts the other hand on the abdomen to palpate the uterus and ovaries. The rationales for a pelvic exam in asymptomatic women boil down to these:
- Screening for Chlamydia and gonorrhea
- Evaluation before prescribing hormonal contraceptives
- Screening for cervical cancer
- Early detection of ovarian cancer
None of these are supported by the evidence. Eliminating bimanual exams and limiting speculum exams in asymptomatic patients would reduce costs without reducing health benefits, allowing for better use of resources for services of proven benefit. Pelvic exams are necessary only for symptomatic patients and for follow-up of known abnormalities. (more…)
Is unmedicated natural childbirth a good idea? The American College of Obstetrics and Gynecology (ACOG) points out that
There is no other circumstance in which it is considered acceptable for a person to experience untreated severe pain, amenable to safe intervention, while under a physician’s care.
It is curious when an effective science-based treatment is rejected. Vaccine rejecters have been extensively discussed on this blog, but I am intrigued by another category of rejecters: those who reject pain relief in childbirth. They seem to fall into 3 general categories:
- Religious beliefs
- Objections based on safety
1. “In pain you will bring forth children” may be a mistranslation, and it certainly is not a justification for rejecting pain relief. Nothing in the Bible or any other religious text says “Thou shalt not accept medical interventions to relieve pain.” Even the Christian Science church takes no official stand on childbirth and its members are free to accept medical intervention if they choose.
2. The natural childbirth movement seems to view childbirth as an extreme sport or a rite of passage that is empowering and somehow enhances women’s worth. Women who “fail” and require pain relief or C-section are often looked down upon and made to feel guilty or at least somehow less worthy.
3. I’m not impressed by religious or heroic arguments, although I support the right of women to reject pain relief on the autonomy principle. What inquiring science-based minds want to know is what the evidence shows. Does avoiding medical treatment for pain produce better outcomes for mother and/or baby? It seems increasingly clear that it doesn’t. A new book, Epidural Without Guilt: Childbirth Without Pain, by Gilbert J. Grant, MD, helps clarify these issues.
More and more American women (1 in 200) are opting for home birth, and midwife-assisted home birth is common in other developed countries. How safe is it compared to birth in a hospital? A new study sheds some light on the subject. It was recently published in the American Journal of Obstetrics and Gynecology: Maternal and newborn outcomes in planned home birth vs planned hospital births: a metaanalysis, by Wax et al.
All the existing studies have flaws. It would be ideal to do a study where women were randomly assigned to home or hospital birth; that isn’t possible, so we have to fall back on studies that are possible. Just comparing home births to hospital births isn’t good enough, because high-risk births occur primarily in hospitals, and between 9% and 37% of planned home births end up with transfer to the hospital during labor and are converted into hospital births. Cohort studies comparing planned home with planned hospital births provide the best sources of data by intended delivery location. There have been several such studies, but the numbers were small and the results were inconclusive. This new study is a meta-analysis that combines the data into one large set for better understanding. (more…)
We know that drinking alcohol during pregnancy can cause birth defects; the government-mandated warnings on alcoholic beverage labels constantly remind us of that fact. But toxicologists remind us that the poison is in the dose: what is the dose of alcohol that causes birth defects? Heavy drinking can cause fetal alcohol syndrome, but there is no evidence that light to moderate drinking can cause it. Alcohol has been implicated in a number of other adverse effects on pregnancy and on the fetus. We simply don’t know if there is a threshold dose below which alcohol intake is safe, so the default position of most medical authorities has been to advise total abstinence during pregnancy. This is not a truly evidence-based recommendation, but rather an invocation of the precautionary principle. Those advising complete abstinence have been accused of paternalism and bias by wine-lovers and other critics, for instance here and here.
The literature on alcohol and pregnancy is extensive and confusing. It addresses many different endpoints, looking at effects on children and on the pregnancy itself. The studies are inconsistent in how they define “moderate” or “light” drinking, and they rely on self-reports that may not be accurate.
It would be impossible to read and accurately summarize such a large body of literature (over 21,000 hits on PubMed!), but here are a few examples that illustrate the scope, diversity, and conflicting results of these studies: (more…)
One of the basic principles of science-based medicine is that a single study rarely tells us much about any complex topic. Reliable conclusions are derived from an assessment of basic science (i.e prior probability or plausibility) and a pattern of effects across multiple clinical trials. However the mainstream media generally report each study as if it is a breakthrough or the definitive answer to the question at hand. If the many e-mails I receive asking me about such studies are representative, the general public takes a similar approach, perhaps due in part to the media coverage.
I generally do not plan to report on each study that comes out as that would be an endless and ultimately pointless exercise. But occasionally focusing on a specific study is educational, especially if that study is garnering a significant amount of media attention. And so I turn my attention this week to a recent study looking at acupuncture in major depression during pregnancy. The study concludes:
The short acupuncture protocol demonstrated symptom reduction and a response rate comparable to those observed in standard depression treatments of similar length and could be a viable treatment option for depression during pregnancy.
Editor’s note: Given the controversial nature of the topic, I think it’s a good time to point out my disclaimer before this post. Not that it’ll prevent any heated arguments or anything…
The Science-Based Medicine blog was started slightly over two years ago, and this is a post I’ve wanted to do since the very beginning. However, since January 2008, each and every time I approached this topic I chickened out. After all, the topic of abortion is such a hot button issue that I seriously questioned whether the grief it would be likely to cause is worth it. (Take the heat generated any time circumcision is discussed here and ramp it up by a factor of 10.) On the other hand, there is so much misinformation out there claiming a link between abortion and the subsequent development of breast cancer when the data simply don’t support such a link, and the name of this blog is Science-Based Medicine. Why should I continue to shy away from a topic just because it’s so religiously charged? More importantly, in my discussion how can I focus attention on the science rather than letting the discussion degenerate into the typical flamefest that any discussion of abortion on the Internet (or anywhere else, for that matter) will almost inevitably degenerate into. Indeed, such discussions have a depressing near-inevitability of validating Godwin’s law not once but many times — usually within mere hours, if not minutes.
My strategy to try to keep the discussion focused on the science will be to stay silent about my own personal opinions regarding abortion and, other than using it to introduce my trepidation about discussing the topic, the religious and moral arguments that fuel the controversy. That’s because the question of whether abortion is the murder of a human being, merely the removal of a lump of tissue, or somewhere in between is a moral issue that, at least as far as I’m concerned, can’t ever be definitively answered by science. That is why it is not my purpose to sway readers towards any specific opinion regarding the morality of abortion. Indeed, I highly doubt that any of our readers care much about my opinions on the matter. On the other hand, I would hope that I’ve built up enough trust over the last two years that our readers will be interested in my analysis of the existing data regarding something another related issue. It is my purpose to try to dispel a myth that is not supported by science, specifically the claim that elective abortion is causes breast cancer or is a very strong risk factor for its subsequent development. That is a claim that can be answered by science and, for the most part, has been answered by science with a fairly high degree of certainty. Despite the science against it, the medical myth that abortion causes breast cancer or vastly increases the risk of it is, like the myth that vaccines cause autism, a manufactroversy that won’t die, mainly because it is largely fueled by religious beliefs that are every bit as immune to science as the ideological beliefs that drive the antivaccine movement.
Between 3-4% of babies begin labor in the breech (bottom first) position, increasing the risk of neonatal morbidity and mortality. Pre-emptive C-section has become the preferred method of delivery for breech babies, but now some are questioning this recommendation. The controversy is fueled by differing appraisals of the danger and by differing assessments of the whether any risk of neonatal death can be justified in the age of the safe Cesarean.
The best conducted and most important study comparing breech vaginal delivery with elective C-section is the Term Breech Trial (TBT) conducted by Mary Hannah and colleagues. It is the only randomized control trial of its kind.
… [W]e found that the fetuses of women allocated planned caesarean section were significantly less likely to die or to experience poor outcomes in the immediate neonatal period than the fetuses of women allocated planned vaginal birth. Although some of the deaths in the planned vaginal birth group were related to difficulty with vaginal breech delivery, others were clearly associated with problems during labour. Thus the avoidance of labour and vaginal breech delivery could have contributed to better outcomes with planned caesarean section…
A more recent trial, the PREMODA (PREsentation et MODe d’Accouchement: presentation and mode of delivery) study produced different findings and as a result, some obstetricians have been calling for a re-evaluation of the standard recommendation for C-section delivery of a breech baby. (more…)
As a mother, I am a passionate advocate of breastfeeding and I breastfed my four children. As a clinician, though, I need to be mindful not to counsel patients based on my personal preferences, but rather based on the scientific evidence. While breastfeeding has indisputable advantages, the medical advantages are quite small. Many current efforts to promote breastfeeding, while well meaning, overstate the benefits of breastfeeding and distorts the risks of not breastfeeding, particularly in regard to longterm benefits.
As Joan Wolf explains in an article entitled Is Breast Really Best? Risk and Total Motherhood in the National Breastfeeding Awareness Campaign:
… Medical journals are replete with contradictory conclusions about the impact of breast-feeding: for every study linking it to better health, another finds it to be irrelevant, weakly significant, or inextricably tied to other unmeasured or unmeasurable factors. While many of these investigations describe a correlation between breast-feeding and more desirable outcomes, the notion that breast-feeding itself contributes to better health is far less certain, and this is a crucial distinction that breast-feeding proponents have consistently elided. If current research is a weak justification for public health recommendations, it is all the more so for a risk-based message that generates and then profits from the anxieties of soon-to-be and new mothers…
Wolf describes the problems with many studies of breastfeeding, particularly those that focus on long term outcomes:
In breast-feeding studies, potential confounding makes it difficult to isolate the protective powers of breast milk itself or to rule out the possibility that something associated with breast-feeding is responsible for the benefits attributed to breast milk. As the number of years between breastfeeding and the measured health outcome grows, so too does the list of possibly influential factors, which means that the challenge is magnifiedwhen trying to evaluate long-term benefits of breastfeeding… Breast-feeding, in other words, cannot be distinguished from the decision to breast-feed, which, irrespective of socioeconomic status or education,could represent an orientation toward parenting that is itself likely to have a positive impact on children’s health. In instances such as this, in which the exposure (breast-feeding) and confounder (behavior) are likely to be very highly correlated, confounding is especially difficult to detect. When behavior associated with breast-feeding has the potential to explain much of the statistical advantage attributed to breast milk, the scientific claim that breast-feeding confers health benefits … needs to be reexamined.
The new mantra of midwives and their advocates is “evidence based practice.” Lamaze, the childbirth education organization has changed the name of their blog to “Science and Sensibility” emphasizing the importance of science and promising:
Lamaze education and practices are based on the best, most current medical evidence available, and can help reduce the overuse of unnecessary interventions while improving overall outcomes for mothers and babies.
But midwives and childbirth educators like Lamaze have a problem. The scientific evidence often conflicts with their ideology. They could address this problem in several ways. Midwives could modify their specific ideological beliefs on the basis of scientific evidence. Childbirth educators could question whether ideology has had an inappropriate impact on the promulgation and validation of their recommendations. Both those approaches would involve a threat to cherished beliefs. They, therefore, have taken a different approach. They’ve tried to justify ignoring scientific evidence.
As midwives Jane Munro and Helen Spiby have documented in The Nature and Use of Evidence in Midwifery, the first chapter of their book Evidenced Based Midwifery, midwives were initially enthusiastic about basing clinical practice on scientific evidence. That’s because they had long told each other that midwifery was “science based” while obstetrics was not:
At the beginning of the evidence based practice movement, much of the midwifery profession responded enthusiastically to the potential for change… Evidence based practice was seen to be offering a powerful tool to question and examine obstetric-led models of care that had dominated the previous decades. The results of such examination could have meant ‘starting stopping’ the unhelpful interventions that had embedded themselves in common practice …