This week we have been talking about pre-pregnancy obesity. We looked at the increasing rates of obesity, then talked about the physiology of obesity and how it increases risks during pregnancy. Today we will turn our attention to what midwives can do. How do we provide the best evidence-based care for obese women?
Midwives don’t seem to be very good at dealing with obesity. Some researchers asked a group of midwives to recruit women with a BMI >30 into a study on the effects of a dietary intervention. But the researchers were actually interested in what the midwives would do. During the four months of recruitment, the midwives only talked 14% of the eligible women. Why? The midwives said they had personal and professional reasons that made them reluctant to talk about obesity with the women.
I get it. You probably get it too. It’s rude. It is embarrassing for the woman. She might be offended. She might get angry. Midwives are supposed to be encouraging, but being told you are obese might undermine the woman’s confidence in her body. But to ignore her health risks is unfair to her. Continue reading
The problem is that reducing risk is out of the midwives hands. Really, the answer seems to be that you have to somehow convince the woman to make the dietary and lifestyle changes to stay within the Institute of Medicine (IOM) weight gain guidelines.
Coming to Terms with the Guidelines
I have to tell you, when I first heard about the guideline changes I was angry and convinced the science had to be bad. How can the IOM recommend that women gain less weight than the baby and placenta and fluid weigh. This is essentially recommending that women diet during pregnancy and I was raised in the natural birth world where pregnant women don’t diet. This had to be a mistake. Continue reading
We have been discussing pre-pregnancy obesity, and today we turn our attention to the effects of obesity on pregnancy. Before we begin, I just want to make sure we recognize the difference between pre-pregnancy obesity and excess gestational weight gain. Both bring increased risk to pregnancy, but they are different risks.
Which brings up another point to remember, these are only risks which are measured by the odds of something happening. A risk is not an absolute, it is only an estimate of the potential for a problem. The odds of an event happening is measured by looking at a large number of people and seeing how many have any specific problem. But an individual doesn’t get 30% of a problem – they either have the problem or they do not. This is risk.
When I read popular literature about obesity and pregnancy, I read about a very limited set of problems. These problems begin with the labeling of obesity as a risk category for pregnancy, which allows the mother fewer options and results in unnecessarily high cesarean rate for obese women. My concern with this line of reasoning is not that it is necessarily wrong, but that it is dreadfully incomplete and gives the false impression that obesity adds no REAL risks to the health of mother or baby.
Pregnancy Induced Hypertension and Gestational Diabetes
We know the adipokines (hormones produced by adipose tissue) increase risk for hypertension, and we see this remains true in pregnancy and postpartum. Women with a BMI >30 have a diminished vascular responsiveness during pregnancy. And Instead of a normal postpartum dip in blood pressure, their blood pressure seems to be reset at a higher level. Estimates of hypertension in pregnancy increase with BMI from less than 1% to about 17% as BMI increases.
In fact, the odds of pregnancy hypertension appears to increase with increasing BMI. So while overweight women have an odds ratio of 1.99 (about twice as likely to have pregnancy induced hypertension), women with BMI >40 have an odds ratio of 4.26 or more than 4 times the odds of developing hypertension. In this study on women with BMIs over 40 (33% were having their first baby), they found 1/3 of the women were admitted to the hospital during their antenatal care – 61% of those admissions were for hypertension treatment.
This still means about 80% of women with BMIs >40 will not develop PIH. But remember, 20% is the same as 1 in 5. This means that while on average 1 out of 100 normal weight women will develop PIH, 1 in 20 obese women and 1 in 5 women with a BMI >40 will develop PIH.
Just like hypertension, the odds for gestational diabetes increases with increasing BMI. Women with a BMI over 40 had over 3 times the odds of developing gestational diabetes. This means that while we expect about 1 in 25 normal weight women will develop gestational diabetes, about 1 in 10 obese women will develop gestational diabetes.
And these numbers are probably low estimates. A different study found the prevalence of gestational diabetes was 19% in women with BMI of 40 or higher. This means 1 in 5 women with BMI at or above 40 developed gestational diabetes in this study.
We can debate appropriate cut-off levels for hypertension or diabetes. We can be frustrated that we don’t have better treatment options for women. But we cannot ignore that the physiological effects of obesity change a woman’s ability to maintain her health in pregnancy.
What about other risks?
Studies repeatedly show risks such as sepsis and thrombo-embolism have a higher odds of occurring for obese women. And this makes sense when we consider the effect of the adipose hormones. Remember they play a role in immune function and clotting factors – so we could expect if the levels of fat hormones are out of whack we would see more infection and thrombo-embolism problems.
Particularly frightening is the strong associations between obesity and preeclampsia. The odds ratios are the same as the Pregnancy Induced Hypertension ratios with women in the highest BMI category more than four times as likely to develop preeclampsia. And while a nullipara had to have BMI>40 to be in the highest risk group, a multip only needed to have a BMI>30.
Remember, some women will only have one problem while others will have multiple. The best estimates are that 1 out of 3 obese women will not have a normal pregnancy. That means 2 out of 3 will continue without problems.
And, we know obese women are more likely to give birth via cesarean, with severely obese (BMI>40) with at least 3 times the odds of giving birth via cesarean. Yes, there is a difference in elective cesarean, but the rates of emergency cesarean (or decision to cesarean made after labor has started) are actually higher than the elective cesarean group.
One of the problems for an obese woman is that it is going to take her longer to labor. It is not a difference in uterine contractility. The contractions themselves take longer to open the cervix in obese women. In fact, it even takes longer for an obese woman to even start labor. So there is one silver lining – obese women actually have a lower rate of spontaneous preterm birth.
I could not find hypotheses about why the contractions of the same strength are not effective on the cervix of an obese woman. But regardless of the reason, it takes about 1.2 hours more for an obese nullip to reach 10cm. And because of this “slow to start” labor reality, an obese woman is 2.5 times more likely to be induced – but this is also due to the higher rates of induction for preeclampsia.
But the higher rates of cesarean add another concern for obese women. The odds of epidural failure is higher, but so is the failure rate for tracheal intubation to allow for general anesthetic. Higher rates of wound infection have led to recommendations for higher or longer doses of prophylactic antibiotics and different surgical closure methods. As we said, an obese woman has much higher odds of a clot. And when she has her next baby, her odds of VBAC failure nearly double.
Risks for the Baby
Obese women are more likely to have infants with congenital deformities like neural tube defects and congenital heart disease. The odds for congenital heart disease increase with increasing BMI, so while there is a 25% increase for women with BMI 30-39, there is a 50% increase for women with BMI >40.
Obese women have at least a 50% increase and possibly over 200% increase in odds for neural tube defects. In fact, in the UK guidelines now recommend a 5mg daily folic acid supplement for pregnant women with BMI >30.
But dysfunctional placentas are not only affecting development. They seem to be affecting the ability of the baby to survive. It turns out, stillbirth is nearly twice as likely in obese compared to non-obese women – In the UK (where better public health records are kept) almost 1/3 of the women who have a stillborn infant or dies in the neonatal period is obese.
The increased risks for both mother and baby with pre-pregnancy obesity are real. But remember, these are risks – not absolutes. Tomorrow we will talk about what midwives can do to help women reduce the risks.
Before we go any further, I want to make sure we are all defining obesity the same. Obesity is defined as an abnormal or excessive fat accumulation that may impair health. In pregnancy, we use the pre-pregnancy BMI estimate to assess overweight and obesity.
One of the things to understand when you read news articles is that obesity can be measured in several ways. You can use waist circumference or measure percentage of body fat, or you can ask people to report their height and weight and calculate a BMI. Continue reading
I promised last month to come back to our discussion about obesity and midwifery, and I am keeping that promise. Our discussion is going to stay focused on pre-pregnancy obesity, and we will start today by discussing the increase in obesity. Tomorrow we will begin to talk about the increased risks for mother and baby, along with the physiology behind those risks and how to reduce risks. Friday, we will wrap up our discussion by considering how pre-pregnancy obesity affects midwifery care.
So to start, let us consider some surveillance information from the Centers for Disease Control and Prevention (their public data is published in maps so it is easy to see changes). Scroll down a bit and check out the slideshow for the History of State Obesity Prevalence. You can stop the slideshow and move to the first slide representing 1985 and notice how no state had an obesity rate greater than 15%. Slowly move the slideshow forward and watch what happens once you pass 1990. Continue reading
A Study out of the University of the Sunshine Coast is looking for parents, both men and women, over 18 years old who feel the birth experience with their child was traumatic.
From the website:
The volunteers will be invited to complete an online survey containing 121 questions which will take approximately 20 to 30 minutes. The survey will investigate previous mental health, symptoms of posttraumatic stress disorder, coping strategies, parenting self-efficacy, and relationship with spouse quality. Questions include asking about anxiety, depression, recurring memories of the traumatic experience, and any positive and negative feelings about your baby.
If you think your child’s birth was traumatic, and this sounds interesting, I encourage you to head over to the survey and start filling it out. As a research participant, you always have the right to change your mind or stop completing the survey if it makes you uncomfortable.
You can read about the study, and gain access to the survey here: Parental Mental Health Following a Traumatic Childbirth Survey.
Don’t forget to have your male or female partner also complete the survey. The childbirth experience affects the whole family.
Last week, At Your Cervix wrote an interesting post about the things she wishes she had learned in Midwifery School. A great read for anyone still in school, or planning to attend school soon. Why? Because it can help you focus time on learning these things.
I add extra agreement to points 2 and 3. These issues are so important for women to find birth control that works well for them, but it was very under-taught in my program as well.
I moved into research rather than practice, so I don’t have much to add to this list relevant to working with patients. So I need to rely on you, dear readers.
What things do you wish you had learned?
A friend posted this article today, which reminded me of a growing problem in health care–patient satisfaction isn’t correlated with better patient outcomes.
[In fact, the most satisfied patients are 12 percent more likely to be hospitalized and 26 percent more likely to die, according to researchers at UC Davis. “Overtreatment is a silent killer,” wrote Dr. William Sonnenberg in his recent Medscape article, Patient Satisfaction is Overrated. “We can over-treat and over-prescribe. The patients will be happy, give us good ratings, yet be worse off.”]
I personally get stuck in this problem. The world of pregnancy and birth are a little different from most types of health care, because most of our patients are actually healthy. And for the most part, most of what our patients want isn’t going to make any big differences in the measured outcomes (i.e. maternal mortality does not increase because women listen to music and walk around during labor).
But the question actually goes deeper. If patient satisfaction is not related to better outcomes in pregnancy and birth, would that mean something is wrong with our concept of autonomy? I could see this answered both ways, so I would love to know your thoughts on it.
First, I can see that with autonomy comes the right to choose to not have the better outcome. If we truly value patient autonomy it means we must accept this balance as desirable.
I had the extreme pleasure of landing on the Urban Village Midwife blog tonight. I was instantly connected to Sherry Payne — this is a woman whose midwife heart beats like mine.
Research, disparities, increasing midwifery workforce…and she comes at it from a community health perspective.
In case you are thinking this is “just” a midwifery student with big ideas, she is a woman with a productive history of advocacy and knowledge generation. She is an editor for a research journal. She sits on the board of CIMS. This is a woman who has been active in maternal health, and is using midwifery training to strengthen her ability to make change.
I’m suddenly sad I didn’t attend the ACNM Annual Meeting — I’m sure I would have met her there. Maybe she’ll be at ICM next week. Or maybe I just have to wait a bit longer since she must be even more busy than me!
It’s nice to know you exist Sherry Payne, and I look forward to opportunities to work with you in the future.
The rest of you, go read her wonderful interview about disparities in breastfeeding.
No, researchers don’t have a way to test the uterus per se, but a group did find a way to test placentas.
That’s right…a group of researchers went searching for microorganisms in placentas. They found some. The study is showcased in a story at the New York Times.
So what does this mean? We can’t be sure yet. Like all good research, it answers one question and poses many more.
Do different microbial ecosystems lead to different pregnancy outcomes? If so, what are the “bad” ecosystems and what can we do about them?
What affect does antibiotic administration have on the normal uterine flora? Can antibiotics in labor cause a lasting effect on the placental flora — and would this alter the baby’s flora?
Remember my previous questions about the microbiome and infertility? What role does uterine microbial ecosystem play in infertility?
Other than antibiotics, what things alter the uterine and placental microbiomes?
Sending much love to the microbiologists who are working to find answers to these, and many more questions. I personally can’t wait to read more.