Research shows that women do of course sweat, and like men sweat more with exercise. The difference is in volume of sweat. A recent study in the Journal of Experimental Physiology found that women, whether fit or not, are less able to use sweating to get rid of body heat than men. This is expecially true of unfit women. An article in the NY Times by Gretchen Reynolds discusses the results of a simple but interesting study where fit and unfit men and women are evaluated for their sweat production, body temperature, and physiologic responses to exercise in a hot environment. It shows once again that men and women are different.
Most of you have probably heard of the BRCA 1 and BRCA2 gene mutations, that can predispose patients with mutations of these genes to breast, ovarian and other cancers. BRCA1 and BRAC2 are proteins that play a key role in the repair of damage in the double stranded DNA of cells. When there is a mutation in one of the BRCA genes, cells are especially vulnerable to inhibition of a second type of DNA repair that repairs single strand “nicks” in the DNA that requires an enzyme called PARP (Poly ADP ribose polymerase). Two investigational products are currently in phase 1 and phase 2 clinical trials for use in patients with advanced cancer. The two drugs currently in studies are olaparib owned by Astra Zenica and BSI-201 owned by Sanofi Aventis. Up to this point the PARP inhibitors have been most promising in patients with BRAC mutations, and are furthest along in advanced breast cancer patients. The hope is that these drugs will enhance the effect of chemotherapy by preventing the cells damaged by the chemotherapy from repairing their DNA damage and surviving.
The PARP drugs so far have been well tolerated and seem to have few serious side effects. Cheers to out to our bench scientists doing basic science for discovering these DNA repair pathways, and taking that knowledge and using it to develop yet another promising class of drugs. I have a vested interest in these trials as my wife has a BRCA2 gene mutation and is getting treatment for advanced ovarian cancer, so stay tuned for any further advances in studies on these new drugs.
Kenny Lin MD is a family physician who posts regularly at Common Sense Family Doc. He always has well researched and thought out opinions, and this is a good example of his writing, first posted at his site on July 29, 2010.
Thanks to a recent pronouncement from the American College of Obstetricians and Gynecologists, my two-year old daughter, who arrived via a vaginal birth after Cesarean section (VBAC), may not be a medical rarity for much longer. In a previous post, I discussed possible causes for the steep 15-year decline in the percentage of U.S. women who have delivered a child vaginally after a previous Cesarean birth (currently fewer than 1 in 10). In March, at a conference held at the National Institues of Health in Bethesda, Maryland, an expert panel concluded that the scientific evidence did not support ACOG’s existing recommendation that surgical and anesthesia personnel be “immediately available” during a trial of labor. However, they found evidence that this restrictive requirement had caused many hospitals without 24-hour availability of these services to discontinue VBAC entirely.
To its credit, last week ACOG released an updated version of the guideline that states that a trial of labor is a reasonable option for the vast majority of women who desire a vaginal delivery after a previous Cesarean, including those who have had more than one prior Cesarean and those carrying twins. While continuing to assert that mothers and babies are best served by access to emergency resources, they add: “Respect for patient autonomy also argues that … [an institutional no-VBAC policy] cannot be used to force women to have cesarean delivery or to deny care to women in labor who decline to have a repeat cesarean delivery.” Amen.
Now I’ll to turn to another controversial maternity care topic: home birth. The subject of a widely viewed 2008 documentary and Time Magazine story, out-of-hospital births represented less than 1 percent of all births in the U.S. in 2005, according to government researchers. A recent meta-analysis of previous studies comparing planned home and planned hospital births that concluded that the former was “associated with a tripling of the neonatal mortality rate” elicited a variety of reactions from health professionals in the U.S. and abroad, ranging from ACOG’s reiterating its opposition to home births to calls for more research by the American College of Nurse Midwives and the UK’s Royal College of Obstetricians and Gynecologists.
I agree that more research is needed. But as for the analysis itself, there are at least two reasons to question whether it should cause many (or any) women to reconsider their home birth plans. First, while “tripling” in neonatal deaths sounds scary, this is a relative rather than an absolute difference in risk. Reading the fine print, neonatal death occurred in 0.15 percent for planned home and 0.04 percent for planned hospital births. That’s an absolute risk difference of just 0.11 percent, or about 1 extra death for every 1000 births. This difference is very close to the small increased risk of neonatal death during attempted VBAC versus repeat Cesarean section (0.8 extra deaths for every 1000 births), which ACOG has acknowledged should be a mother’s choice.
Second, all but 3 of the 12 studies included in the meta-analysis were conducted prior to the year 2000, in populations with much lower Cesarean rates than in the U.S. Overall, only 9.3% of women in the planned hospital birth groups had Cesarean deliveries – a far cry from the 32% that currently occur in the U.S. So while this study’s results are most applicable to countries in other parts of the world that have Cesarean rates of 10% or less, it’s not clear if it captured the maternal complications that invariably result from doing 3 times as many surgeries.
The bottom line? The available evidence indicates that planned home birth is no riskier for babies, compared to planned hospital birth, than is attempting VBAC compared to choosing a repeat Cesarean delivery.
Dr. Amy Tuteur is an obstetrician who posts as The Skeptical OB regularly. Her posts are always well thought out and articulate and usually contrarian. Her posts are more detailed than mine tend to be, and tend to articulate her point of view explicitly. I hope you enjoy this article reposted with her kind permission. Check out her blog to see other timely and interesting material.
Child centered parenting is a relatively new phenomenon, made possible by the increased security and increased leisure of contemporary life. Where once it was commonplace to send even young children out to work to contribute to the family’s support, childhood is now acknowledged as a protected space.
The change in philosophy has led to a change in the expectations about mothers. After World War II mothers, who were previously held responsible for raising healthy children with good manners, were also tasked with raising emotionally secure adults. This responsibility was seen as requiring a “child centered” approach, giving pride of place to children’s needs over mothers’ needs.
So far, so good. But in the intervening years, the purported responsibilities of mothering have grown dramatically, notably expressed as a commitment to “intensive mothering” also known as attachment parenting. Among those responsibilities is one entirely new claim, the notion that mothers are not responsible merely for physical health, acculturation and emotional security, but are also responsible for a child’s brain development. Whereas there is copious scientific evidence to support assigning the health and socialization tasks to mothers, there is little to none supporting the notion that mothers exercise substantial control over children’s brain development. No matter. An virtual industry has arisen to promote the idea that only mothers can develop a child’s brain.
Canadian sociologist Glenda Wall details the new responsibility in her paper HYPERLINK “http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VBD-4YJ14B4-2&_user=10&_coverDate=06%2F30%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1370757039&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=5b94801a0d125d0dc70be71a733e1ab6″HYPERLINK “http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VBD-4YJ14B4-2&_user=10&_coverDate=06%2F30%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1370757039&_rerunOrigin=scholar.google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=5b94801a0d125d0dc70be71a733e1ab6″Mothers’ experiences with intensive parenting and brain development discourse.
Over the 1990s and into the current decade government agencies, non-profit foundations, and child-rearing experts undertook to educate parents and the public in general about the importance of spending ample, one-on-one quality time with children in order to stimulate brain development and future brain potential…
The claims being made in the advice literature that has resulted, while presented as fact, have been the subject of some scientific debate. Several authors suggest, among other things, that there is in fact little evidence in the field of neurology to support the claim that ‘extra enrichment’ … has any beneficial effect on future intelligence or success.
Despite scientific critiques however, the brain development advice itself borrows from the language and authority of neuroscience to frame children’s brains as technologically complex machines that need the correct inputs in order to attain maximum efficiency at a later time …
Wall explains how this new responsibility has put increased pressure on mothers.
Parents and caregivers are cast as the engineers and programmers charged with the task of making the correct inputs, and the potential consequences of neglecting to give children what they need in this regard are portrayed as dire…
In other words, there are now new ways for mothers to screw up and bring opprobrium down on themselves. Not only are mothers blamed for children’s poor manners and psychological issues, but they are now held to be at fault if their children are not intellectually superior.
Wall’s critique is insightful, not merely because she explores the lack of evidence for our new found belief that mothers are responsible for optimal brain development. Wall also casts light on the cultural assumptions that buttress this belief: the assumption that we exercise far more control over health and development than we actually do, and the assumption that parents should do more than aspire to intellectual and professional success for children, they should consciously plan for it.
In an age of intensive, and child-centered parenting, the imperative for parents to plan for, control, and manage the lives of their children to optimize their future chances … The institutional practices that have grown up around prenatal education and planning, the promises made in the marketing of educational toys, and the promotion of lessons, and various types of cultural enrichment all contribute to a cultural understanding that parents (and especially mothers) have a duty, and the ability, to control and shape the lives of their children to a very fine degree.
These assumptions have profound implications for mothers and children.
The view of childhood embedded in brain development discourse is certainly one of children as highly malleable, as parental projects full of potential, but potential that can only be activated with appropriate and intensive parental inputs. Children’s current happiness is also emphasized less in this discourse than is their future potential for success.. Rather it is desirable only in so far as it contributes to potential success, and coincides with parental behavior that promotes brain development. At the same time childhood intelligence has become elevated as an important virtue (over and above happiness) and manifestations of it are more likely to be seen as evidence of good parenting.
Hence the moralizing and hectoring that is so common among attachment parenting proponents. Everything they champion – breastfeeding, babywearing, etc. – is not merely a choice, but it is supposedly a demonstration of commitment to raising smarter, more successful children. In other words, mothering has become a competition.
The focus on intelligence in brain development discourse is linked to an implicit endorsement of competition in this regard between children and between parents. As Nadesan notes … the brain development turn in the 1990s accelerated a trend in parental desires to have children who exceed the norm intellectually…
Proponents of attachment parenting need to look carefully at the assumptions underlying their philosophy and stop the hectoring and moralizing that seem to flow from their philosophy.
AP proponents assume that they can enhance the neurodevelopment of their own children and disparage mothers who refuse to optimize the neurodevelopment of their children. Yet there is really no evidence that mothers’ choices enhance neurodevelopment and hence no basis to assume that mothers who make different choices don’t care about their child’s intelligence.
AP proponents assume that children in their role as future adults are in competition with one another and that mothers should strive to give their children competitive advantages. They also assume that parents are in competition with each other and that a child’s achievements are weapons in that competition. The parent with the smartest child wins.
Of course it takes many years to find out whose child is the smartest and no one wants to wait. Because of their implicit belief in their ability to control outcomes, AP proponents don’t bother to wait. They simply compete on the basis that their children are going to be smarter than those of women who make different choices!
Attachment parenting is a parenting philosophy, but it is also a reflection of cultural assumptions and simple human competitiveness. AP proponents believe that they are fashioning superior children and have contempt for those who make different parenting choices. They assume, imply and often flat out assert that mothers who make different choices don’t care to give their children a competitive advantage. It hasn’t occurred to them that many mothers know that AP practices don’t give children a competitive advantage and indeed reject the notion that raising children has anything to do with competition.
I urge readers to submit a guest post. I’d love to give you a forum to be heard.
I just read an interesting, if a bit esoteric article on predicting which female athletes are at risk for ACL injuries. Some of you may recall a prior post on ACL injuries in girls: ACL injury prevention in female athletes
This article gives hope that we will be able to more accurately predict girls at risk to get them on training programs to reduce their excess risk of this serious athletic injury.
I’ve always thought birth pools ana underwater birth was wierd, unnatural and seemed dangerous. Advocates are passionate about its benefits, but it looks like they are ignoring the risks. I turned away a couple of patients years ago because water births just seemed too frightening for me to accomodate. Now the risks are becoming more understood. Here is an excellent article on KevinMD by Amy Tuteur MD who posts as The Skeptical OB.
Waterbirth dangers to newly born babies
by Amy Tuteur, MD
Waterbirth has become a central component of “natural” childbirth dogma, despite the fact that for primates giving birth underwater is entirely unnatural. You don’t need a medical degree to appreciate the idiocy of birth in water. read more
Ms. Navratilova has Ductal Carcinoma in Situ (DCIS). Sounds scary, and all cancer is, but DCIS is really a diagnosis of cancer before it starts to invade tissues outside the milk ducts of the breast. It is a cancer that really can only be discovered by imaging, usually by mammography since at this early stage it is rarely large enough to feel on examination. Ms. Navratilova probably got lucky, given that she tells us that she had not had a mammogram for four or five years prior to the one that discovered her cancer. Breast cancer tends to be a slowly developing disease, which is one of the reasons that mammography is so effective. The cancer often develops in the milk ducts, and when it is limited only to the duct itself, and has not invaded through the duct wall and into the surrounding breast tissues it is called “in situ.” In situ is defined as, “situated in the original, natural, or existing place or position” at dictionary.com . THe good news for Martina is that it is almost universally cured with treatment. Treatment is usually local surgical excision (lumpectomy) and radiation therapy, or by mastectomy without radiation therapy. Although lumpectomy and radiation therapy has a slightly higher local recurrence rate than mastectomy survival rates are similar.
Ductal carcinoma in situ (DCIS; also known as intraductal carcinoma) is the most common type of non-invasive breast cancer. DCIS means that the cancer cells are inside the ducts but have not spread through the walls of the ducts into the surrounding breast tissue.
About 1 in 5 new breast cancer cases will be DCIS. Nearly all women diagnosed at this early stage of breast cancer can be cured. A mammogram is often the best way to find DCIS early.
When DCIS is diagnosed, the pathologist (a doctor specializing in diagnosing disease from tissue samples) will look for areas of dead or dying cancer cells, called tumor necrosis, within the tissue sample. If necrosis is present, the tumor is likely to be more aggressive. The term comedocarcinoma is often used to describe DCIS with necrosis.
It is not clear from what I can find whether Ms. Navratilova has comedocarcinoma or a less aggressive type of DCIS, but regardless she has a great prognosis. Score one success for mammography.
Of note Ms Navratilova fits some but not all of the typical risk factors for breast cancer. At 55 years old she is clearly in the age range at risk. Breast cancer incidence increases with age. She certainly is not obese and has had no lack of physical exercise, but women who have not had children are a slightly higher risk for breast cancer as are women who have not breast fed an infant, so Ms. Navratilova fits those aspects of a high risk profile. Family history and estrogen use, either as oral contraceptives or postmenopausal hormone replacement therapy, are also risk factors.
Exercise alone does not seem to be effective in preventing weight gain once a woman is already heavy. The latest JAMA issue reports on a huge study trying to see if different levels of exercise prevent weight gain in women. This study looks at the 34,000 women in the Women’s Health Study, a huge cohort of women which has already reported on aspirin use and other variables. The results are not encouraging. Regular exercise was only associated with lack of weight gain in women who were thin (BMI<25) at the start of the study. Women who ranged from upper normal weight (BMI 25-30) to obese (BMI >30) gained weight even if they exercised regularly. The only group of women who did not gain weight over the 13 years of follow up in the study were thin women who exercised regularly for 60 minutes daily of moderate to high intensity exercise. This page effectively describes Aspirin side effects. The take home messages of this study are:
Starting early with prevention of obesity is key. Once overweight it is far more difficult to prevent further weight loss. Multiple prior studies have demonstrated how difficult it is to achieve sustained weight loss.
Calorie restriction is needed to prevent weight gain once overweight. Exercise alone is not sufficient.
The conclusion of this study sums it up pretty well.
“In conclusion, in this large prospective study of women consuminga usual diet, sustained moderate-intensity physical activityfor approximately 60 minutes per day was needed to maintainnormal weight and prevent weight gain. These data suggest that the 2008 federal recommendation for 150 minutes per week, while clearly sufficient to lower the risks of chronic diseases, is insufficient for weight gain prevention absent caloric restriction.Physical activity was inversely related to weight gain onlyamong normal-weight women; among heavier women, there was norelation, emphasizing the importance of controlling caloricintake for weight maintenance in this group.” JAMA. 2010;303(12):1173-1179
Peter Yarrow of Peter Paul and Mary teams up with CBS to make this very cool You Tube video called The Colonoscopy Song promoting colon cancer screening. I got no prize, just good news of a 10 year wait to do it again when I turned 50. I first saw this on KevinMD.com and thought it so fun I have also posted this link to the video.
In the latest issue of the British Medical Journal Hannaford et. al. report on a data of a huge number of women followed for almost 40 years, and look at the death rates in women who have used birth control pills compared to women who never used birth control pills. In fact the overall death rates of pill users is lower in most categories that never users, even when controlled for other risk factors like smoking and socioeconomic status. They found not only do women who have used birth control pills have no increased overall risk of death overall, but that their rate of death is somewhat lower than never-users. The data is sliced and diced in innumerable ways, and the bottom line is that women do not need to worry that birth control pill use now or in the past will lead to a higher change of dying early of a pill related problem.
I like Hannaford’s comment, “I would never recommend that someone use the pill simply to reduce their risk of disease later in life,” he said. “However, if the choice is the pill, this decision does not increase a woman’s risk of long-term death. Indeed it may even have some benefits.”
Published 11 March 2010, doi:10.1136/bmj.c927
BMJ 2010;340:c927
VBAC and Home Birth
Kenny Lin MD is a family physician who posts regularly at Common Sense Family Doc. He always has well researched and thought out opinions, and this is a good example of his writing, first posted at his site on July 29, 2010.
VBAC and home birth: evaluating the evidence
Thanks to a recent pronouncement from the American College of Obstetricians and Gynecologists, my two-year old daughter, who arrived via a vaginal birth after Cesarean section (VBAC), may not be a medical rarity for much longer. In a previous post, I discussed possible causes for the steep 15-year decline in the percentage of U.S. women who have delivered a child vaginally after a previous Cesarean birth (currently fewer than 1 in 10). In March, at a conference held at the National Institues of Health in Bethesda, Maryland, an expert panel concluded that the scientific evidence did not support ACOG’s existing recommendation that surgical and anesthesia personnel be “immediately available” during a trial of labor. However, they found evidence that this restrictive requirement had caused many hospitals without 24-hour availability of these services to discontinue VBAC entirely.
To its credit, last week ACOG released an updated version of the guideline that states that a trial of labor is a reasonable option for the vast majority of women who desire a vaginal delivery after a previous Cesarean, including those who have had more than one prior Cesarean and those carrying twins. While continuing to assert that mothers and babies are best served by access to emergency resources, they add: “Respect for patient autonomy also argues that … [an institutional no-VBAC policy] cannot be used to force women to have cesarean delivery or to deny care to women in labor who decline to have a repeat cesarean delivery.” Amen.
Now I’ll to turn to another controversial maternity care topic: home birth. The subject of a widely viewed 2008 documentary and Time Magazine story, out-of-hospital births represented less than 1 percent of all births in the U.S. in 2005, according to government researchers. A recent meta-analysis of previous studies comparing planned home and planned hospital births that concluded that the former was “associated with a tripling of the neonatal mortality rate” elicited a variety of reactions from health professionals in the U.S. and abroad, ranging from ACOG’s reiterating its opposition to home births to calls for more research by the American College of Nurse Midwives and the UK’s Royal College of Obstetricians and Gynecologists.
I agree that more research is needed. But as for the analysis itself, there are at least two reasons to question whether it should cause many (or any) women to reconsider their home birth plans. First, while “tripling” in neonatal deaths sounds scary, this is a relative rather than an absolute difference in risk. Reading the fine print, neonatal death occurred in 0.15 percent for planned home and 0.04 percent for planned hospital births. That’s an absolute risk difference of just 0.11 percent, or about 1 extra death for every 1000 births. This difference is very close to the small increased risk of neonatal death during attempted VBAC versus repeat Cesarean section (0.8 extra deaths for every 1000 births), which ACOG has acknowledged should be a mother’s choice.
Second, all but 3 of the 12 studies included in the meta-analysis were conducted prior to the year 2000, in populations with much lower Cesarean rates than in the U.S. Overall, only 9.3% of women in the planned hospital birth groups had Cesarean deliveries – a far cry from the 32% that currently occur in the U.S. So while this study’s results are most applicable to countries in other parts of the world that have Cesarean rates of 10% or less, it’s not clear if it captured the maternal complications that invariably result from doing 3 times as many surgeries.
The bottom line? The available evidence indicates that planned home birth is no riskier for babies, compared to planned hospital birth, than is attempting VBAC compared to choosing a repeat Cesarean delivery.