Dispelling Myths on Pregnancy Exercise

At regular intervals, it becomes necessary to dispel two persistent myths that are often perpetuated by well-meaning care providers. Both of them were debunked long ago, in research literature that is readily available and about which I have written a great deal, including in my chapters on Women and Exercise (editions 3 & 4) and Health Promotion in Varney’s Midwifery (edition 5), in posts on the DTP website, on my Twitter feed (@anncowlin), on DTP’s Facebook page and in a textbook.

DTP_mover1_pregnantThe more common myth is that pregnant women should never let their pulse get over 140 beats per minute. But, more on that one at another time. That was an ACOG guess in 1985 that long ago (1994) was rescinded.

The other is that pregnant women should never begin a new exercise regimen, but only modify (i.e., reduce) what they are already doing. What brings me to write this blog after a blog break (to respond to our expanding pre/postnatal fitness teacher training program) is that this evening I was told the latter myth was promoted by a CNM at a recent nearby conference. A childbirth education colleague alerted me to this occurrence and also to the happy response by an unknown person in the audience, who chose to differ with the midwife, citing Dancing Thru Pregnancy® as her example!! Thank you to this responder.

Let me address – yet again – the issue of whether it is safe for pregnant women to begin an exercise regimen after they become pregnant. The caveat I offer at the outset is that doing so should be under the supervision of a knowledgeable certified pre/postnatal fitness specialist. Within the profession, the resolution of this question is generally agreed to be the Cochrane Review conducted in 2002, which found that aerobic fitness can be improved or maintained in pregnancy. Improvement requires increasing the level of aerobic challenge. More recently, researchers concluded “….pregnant women benefit from regular physical activity the same way as non pregnant subjects…” and that “…[t]he adoption or continuation of a sedentary lifestyle during pregnancy may contribute to the development of certain disorders such as hypertension, maternal and childhood obesity, gestational diabetes, dyspnoea, and pre-eclampsia.” (Melzer et al. Physical activity and pregnancy: cardiovascular adaptations, recommendations and pregnancy outcomes. Sports Med. 2010 Jun 1;40(6):493-507. 

Put another way, the female is not put together to be sedentary in pregnancy. It is only in recent decades that this is an option. Until the mid 20th Century, activities of daily living required physical fitness, and obesity was rare, along with sedentary behavior. In the last few decades, those who are knowledgeable about the interactions of pregnancy and exercise, and who have the experience of teaching movement to this population, have come to understand how to present activities that improve the factors that improve maternal and fetal outcomes.

Those who are extremely well-versed in the field all agree that cardiovascular (aerobic) fitness during the 6 – 12 month pre-pregnancy period may be the greatest pregnancy enhancement a woman can have. Why? Because endothelial function is greatly enhanced, oxidative stress is reduced, and vascularity is increased by aerobic fitness, and these capacities underly healthy implantation and placental development (see Research Updates 2001-2005, Winter 2005 and Winter 2004 and Update on Immune Function). Barring that, beginning early in pregnancy is helpful because placental development is still underway. Barring that, mild to moderate aerobic activity introduced by 25-30 weeks will produce cardiovascular enhancement by the time of labor. My caveat goes here, too.

All conditions mediated by inflammation are a problem in pregnancy. Physical fitness is a major preventive strategy for inflammation, and pregnancy does not stand in the way.

 

 

Blood Pressure in Pregnancy

I was recently asked some questions regarding blood pressure during pregnancy by my colleagues at Physiquality. In preparing material, I wrote this blog, which includes very basic clinical information and explanations about this topic.

What is the normal range for blood pressure for pregnant women? What readings would fall under high blood pressure?

Blood Pressure (BP) in pregnancy is a complex topic.

First, we need to know: What are the classifications of BP?

The chart below is from the evidence-based 2014 Guidelines of the American Heart Association and the National Heart, Blood and Lung Institute of the NIH. The first number is Systolic BP or during the heart beat. The second number is Diastolic BP or between beats. These numbers are relevant for women of childbearing age.

  • Normal                        <120 mm Hg and <80 mm Hg
  • Pre-hypertensive          120-139 or 80-89
  • High BP Stage 1            140-159 or 90-95
  • High BP Stage 2            ≥ 160 or ≥ 10

Why does low BP (hypotension) occur in a healthy pregnancy?

A healthy pregnant woman with normal BP and no cardiovascular or immune system complications, will have pregnancy BP lower than her non-pregnant BP due to increased progesterone relaxing her vasculature. To create the placental and uterine blood flow, blood volume (V) expands rapidly increasing by around 40%, but stroke volume increases less, so beats per minute (pulse) may increase, systolic BP may drop 5 mm Hg and diastolic may drop 10-15 mm Hg. If V is not adequate with this relaxed vasculature, BP may drop even lower. To help maintain normal BP, women are encouraged to drink sufficient water (about 8 glasses/day) and eat enough protein (about 20-25% of daily intake) to produce a blood volume that will sustain an adequate BP. Other more severe conditions – often genetic – may also be relevant, such as postural orthostatic tachycardia syndrome.

Other causes of hypotension include lying still on the back with legs extended for long periods of time after the first trimester. The weight of the uterus impinges on the vena cava returning blood to the heart, thus reducing BP and blood flow to the uterus and placenta. Also, standing for long periods of time with a minimum of motion, as happens with teachers, cashiers, line workers and nurses in the second half of pregnancy when increasing relaxin and elastin cause further softening of vasculature. This results in difficulty returning blood from the lower limbs and reducing blood flow to the uterus and placenta.

What are hypertensive disorders of pregnancy?

According to the National High Blood Pressure Education Working Group on High Blood Pressure in Pregnancy, hypertensive disorders of pregnancy are presently classified into four categories:

  • Chronic hypertension (pre-existing)
  • Preeclampsia-eclampsia
  • Preeclampsia superimposed on chronic hypertension
  • Gestational hypertension

[The Society of Obstetricians and Gynecologists of Canada categorize these disorders as pre-existing or gestational, with the addition of preeclampsia to either category.]

Chronic hypertension is BP >140/90 prior to pregnancy or before 20 weeks. New onset of high BP after 20 weeks may indicate preeclampsia (PE), which requires further consideration. PE involves other symptoms and organs. It occurs in about 5% of all pregnancies, 10% of first pregnancies and 20-25% of women with a history of chronic hypertension. It is a serious disorder and major cause of adverse maternal and fetal outcomes, including strokes, seizures and restricted fetal growth and development.

The underlying pathogenesis of preeclampsia-ecclampsia is not yet fully understood, but is a fundamental dysfunction of the placenta leading to endothelial dysfunction and vasospasm. Possible causes include pre-existing endothelial dysfunction, metabolic dysfunction, auto-immune responses and infection. It is likely that the placenta is affected very early on, during implantation, trophoblast invasion of the uterus and opening of the spiral arteries to form the blood pool on the maternal side of the placental circulation.

Gestational hypertension is the onset of BP >140/90 after 20 weeks without other features of preeclampsia. About 1/3 of these women develop preeclampsia. Gestational hypertension is highly associated with hypertensive disorders later in life. Diabetes can also be a factor associated with hypertension.

Whenever a woman has elevated BP in pregnancy, she needs to be evaluated and have a follow up course of observation and treatment. At its most severe, a hypertensive disorder can affect all the body’s organs and systems, and can be fatal.

What can pregnant women do (diet, exercise, healthy habits) to keep their blood pressure within a normal range?

Some risk factors for hypotension or hypertensive disorders of pregnancy are inherited, others are a consequence of behavior, and many are a combination.

What can a woman do before pregnancy?

Because the events that pre-dispose a woman to hypertensive disorders may occur before she knows she is pregnant, some efforts at prevention may be helpful in the six months to a year prior to pregnancy. Preparing for the implantation period by maintaining optimal health and fitness is likely the most helpful behavior. Cardiovascular or aerobic fitness, which prevents or reduces the severity of endothelial dysfunction is highly valuable. An adequate daily nutrient intake along with sufficient water, and maintaining a BMI <25 are important factors. Women with elevated blood pressure should discuss with their care provider the balance of sodium and potassium intake, along with the total allowable amounts.

Avoiding infections or illness around the time of conception may be a factor. Hypertensive disorders are mediated by inflammation. Unfortunately, another factor may be the maternal immune response to the fetal DNA. This may also be dependent on combined maternal/paternal immune system responses.

What can a woman do once she is pregnant?

Once a woman is pregnant, maintaining optimal health and fitness continue to be important. Even if there are pre-disposing factors for disorders, she may be able to reduce the severity by staying fit, well nourished and well rested. A balanced and colorful diet, along with avoidance of alcohol, drugs and unsafe behaviors are critical.

The ability to achieve the Relaxation Response, meditation, deep breathing and hypnosis are valuable for acute BP reduction. Each of these skills is mediated by the parasympathetic nervous system response (or alpha brain rhythm) and mitigates the effects of stress on a temporary basis. Cardiovascular or aerobic fitness is effective for long-term BP reduction, as well as cardiovascular health.

Resting on the left side maximizes circulation and – if possible – finding 15 or 20 minutes to rest this way during the day is beneficial, especially if a woman’s work involves standing for long periods of time. Avoiding lying on the back or standing for long periods of time is advisable. Finding a community of support for having a healthy pregnancy can be a great asset, as well.

Safe Pregnancy, Safe Labor, Safe Motherhood

The challenges to safe motherhood vary depending where in the world you live. In some areas the challenge may be to get adequate nutrition or clean water; in other areas, it may be to prevent infection; and in still other locations it may be trying to avoid pregnancy before your body is ready or getting access to prenatal care. In the U.S., it may mean avoiding being sedentary and making poor food choices, or having to deal with the high technology environment of medical birth that can sabotage the innate physiological process of labor and birth.

Birth begins the bonding or unique love between mother and child.

The biology of birth is a complex series of cause-effect processes…baby’s brain releases chemical signals to the mother and the placenta begins to manifest the maternal immune system’s rejection of the fetus.

To help the ball get rolling, relaxation (the trophotropic response) helps promote the release of oxytocin. With the help of gravity, the head presses on the cervix, amplifying the uterine contractions. After an ultra-distance aerobic endurance test, the cervix opens enough to let the baby move into the vagina and the mother’s discomfort moves from sharp cramping into the bony structure as she transitions to the strength test of pushing. She transitions. Relaxation modulates into an ergotropic – adrenal – response to gather her power.

Pushing is an interesting term…more masculine, I think, than the one I prefer:  Releasing. Releasing or letting go of the baby. It’s a catharsis. In this portion of the labor another set of important processes help the baby clear its lungs of amniotic fluid, stimulate its adrenal system and challenge its immune system, as the contractions drive the baby downward. The mother’s deep transverse abdominal muscles – if strong enough – squeeze the uterus like a tube of tooth paste, to aid this expulsion. In the meantime, the labor is helping set up the mother to fall in love and produce milk. When the baby emerges and moves onto the mother’s chest, s/he smells and tastes the mother, recognizing her mother’s flavor and setting up the potential for bonding.

Any way you slice it, there are two parts to safe motherhood. One is a safe pregnancy…healthy nutrition, physical fitness, safe water, infection prevention, support and a safe environment. The other is a safe labor. In a safe labor, there is both an environment that promotes the natural process of labor and the means necessary for medical assistance when needed. Women die at an alarming rate from pregnancy or birth-related problems. Despite some progress made in recent years, women continue to die every minute as a result of being pregnant or giving birth.

What keeps us from having a better record on motherhood is often lack of care in the developing world and too much intervention in the U.S.. They are two sides of a coin. Mothers’ experience and health needs are not on equal footing with other cultural values. In places where basic prenatal care or family planning are low priorities, at-risk women are vulnerable to the physical stresses of pregnancy and birth. In the U.S., machine-measured data is paramount, even if it produces high rates of false positives, unnecessary interventions or counterproductive procedures. We are learning that obesity and sedentary lifestyles have detrimental effects, but fewer pregnant women than their non-pregnant counterparts exercise.

Despite the money spent to support the technological model of pregnancy and birth in the U.S., there are parts of the world – especially Scandinavia, Northern Europe and parts of the Mediterranean and Middle East (Greece, the United Arab Emirates, Israel, Italy and Croatia) – with lower rates of maternal deaths. In fact, in the U.S., maternal deaths are on the rise.

It’s a tricky business. Clearly Western medicine has a lot to offer the developing world when there are medical concerns. On the other hand, importing the U.S. model could create more problems than it solves. Instead, the micro-solutions now being developed in many locations will be observed and evidence collected by organizations such as the White Ribbon Alliance and UNICEF.

There is an effective international midwives model adopted by JHPIEGO, the Johns Hopkins NGO working toward improved birthing outcomes. It assesses the local power structure, social connections, potential for trained birth assistants, and location of available transportation to create a network so that locals will know when a labor is in trouble and who can get the woman to the nearest hospital.

In the U.S., there are in-hospital birth centers that allow low-risk mothers the opportunity to labor and birth in a setting designed to encourage the innate processes. Women are beginning to vote with their feet…staying home for birth. Women are going abroad to give birth. At the same time, women are coming to this country to give birth, believing it is safer than where they are. There are several ways these scenes could play out.

But, I’ll wager, improving outcomes will involve compromise:  Watchfulness and support in most births, plus better ways to assess danger and provide technology. No matter where you live in the world, the solution may be essentially the same.

Preventing Prematurity

Today is a day for bloggers to raise awareness of the growing rate of prematurity in the U.S.  As a pre/postnatal fitness specialist who has been working in the field for more than 30 years, I have a number of thoughts on this topic.

I like to start thinking about this problem by thinking back 50,000 years. Back in the day when survival meant hard physical work. 

Which pregnant women survived?  The strongest, fittest and best fed.

Does it make sense, therefore, that becoming sedentary and eating junk food is going to produce healthy offspring at full term? Well, the evidence says no. This behavior is responsible for some of the growing prematurity. Women who are aerobically fit, eat a healthy diet and maintain a healthy weight generally enjoy these benefits over those who do not:

  • a healthier endometrium into which the zygote will implant
  • a healthier placenta with more nutrient delivery surface
  • reduced risk that the necessary immune system modulations of pregnancy go awry
  • better control of metabolic and cardiovascular factors that can threaten pregnancy, such as gestational diabetes or preeclampsia
  • a greater ability to physically cope with some environmental toxins

There are – of course – factors that affect prematurity in any case. But, to a certain degree, the growing rate of prematurity is another example of lifestyle-caused disorders. Some of the fix therefore requires a lifestyle that is active and health-conscious.

But, I am hopeful. I see – for the first time in a couple of decades – growing numbers of young women interested in living a healthy lifestyle…exercising, eating healthy and seeking to improve environmental conditions. I also see young women interested in preventing poor living conditions and infection rates in this country and in the developing world that have hindered progress in preventing disorders such as gestational diabetes and preeclampsia.

To these young women I say:  kudos. Keep working. We have much work to do.

To young women contemplating pregnancy in their future I say:  become aerobically fit, eat a balanced and colorful diet, spend 15 minutes in the sun most days (or, if you are at risk for skin cancer, take vitamin D), practice meditation or a simple progressive relaxation with deep breathing for 10 or 15 minutes most days.

To all the moms whose babies came too soon, my heart is with you. I know this pain.

Breastfeeding Research Demonstrates More Baby Protections

We have long known that vaginal birth and breastfeeding are key factors in the development of a healthy immune system in infants. Passing through the vagina exposes the baby to an array of bacteria that help stimulate its unchallenged immune system. Breast-fed babies receive anti-bodies, proteins and other molecules that protect it from infection and teach the immune system to defend the infant.

Breastfeeding is key for long-term health.

Recent research at UC Davis has shown that a strain of the bifido bacteria – acquired from the mother – thrives on complex sugars (largely lactose) that were previously thought to be indigestible. The bacterium coats the lining of the immature digestive tract and protects it from noxious bacteria.

This combination of interactions affects the composition of bacteria in the infant gut as it matures. Another example of how evolution has “invented” the perfect nutrition for infants, this research contributes to the notion that evolution has selected for many genes that serve normal birth and breastfeeding by protecting the newborn. Intervening with the normal progression of birth and breastfeeding – while occasionally necessary – interrupts these beneficial adaptations and contributes to allergies and autoimmune disorders.

You can read more about this research in the NYTimes Science section. Our Twitter feed (on the Right side of this blog) will take you to the link for this article. It’s worth the trip!!

Pregnancy Pathway, Pregnancy – Behavior, part 1: Exercise

How lucky is this? Just a few days ago, yet another study was released and has been circulating on Medscape and other medical sites that indicates exercise is beneficial in pregnancy, whether the mother is a previous exerciser or not. Just in time for this entry!

Behavior Affects Pregnancy Outcome

Behavior Affects Pregnancy Outcome

Physical exertion (we call it “exercise” nowadays) is a normal state for healthy humans. Only in the last century has the desire to rest or the need to store extra calories as fat become more possible to achieve than our need to move about to survive.

Pregnancy is a state in which both of these factors (resting and storing calories) are enhanced through organic changes in body chemistry, adaptations that favor fetal survival. The current sedentary lifestyle exaggerates these metabolic changes and results in syndromes that increase the risk for a number of metabolic, cardiovascular and immunological disorders of pregnancy.

When confronted by the idea that it is counterintuitive to think exercise in pregnancy might be safe (let alone beneficial) I am dumbfounded. To me, it is counterintuitive to think that a sedentary lifestyle in pregnancy might be safe!

Burning Calories in Pregnancy Improves Outcomes!

Burning Calories in Pregnancy Improves Outcomes!

What is the evidence that exercise in pregnancy is beneficial? Keep in mind that some studies have been executed more expertly than others. But, what is compelling is that numerous well-respected researchers have sought to test the hypothesis that exercise is not safe, but come away with results that indicate the opposite!

Here are some of the major findings:

• The placenta is larger and has more transport surface in exercisers than sedentary women

• The fetuses of (aerobic) exercising mothers make beneficial cardiovascular adaptations

• Women who do aerobic exercise are less likely to develop severe preeclampsia or gestational diabetes, and the long term health problems that accompany these disorders

• Women who are aerobically fit recover from birth 10 times faster than sedentary women (as measured by time needed to metabolize free radicals produced in labor)

• Women who exercise in pregnancy are more likely to be physically fit in midlife

• Babies of aerobically fit women are at reduced risk for prematurity and low birth weight
DTP_mover2
So, we have arrived at the take-home message: MOVE!! Pregnancy works best when you move and burn calories in a moderate to vigorous fashion. But, alternate this activity with rest and good nutrition, and be sure to stay well hydrated.
If you want more specifics and resources on this topic, try these:
“Women and Exercise” in Varney’s Midwifery.

Pregnancy Pathway, Pregnancy – Maternal Immunological Response

Today: Maternal Immunological Response…or…the Mother/Fetus Dance!

Maternal Immune Response During Pregnancy

Maternal Immune Response During Pregnancy

Back to work! Thank you for your forebearance while we wrote a chapter for a nursing textbook!

During the course of pregnancy, the mother/fetus dance is ongoing. The maternal immune system and the trophoblast cells continue to influence each other even beyond the implantation.

Because the mother’s immune response modulates near the start of each trimester, the fetus is affected to some degree and mounts a response, as well. For a long time it was thought that maternal and fetal DNA material was not exchanged across the placental membrane, however recent findings indicate that there is some exchange of material. Thus, we all carry some portion of our mother’s DNA and our mother carries some of ours.

What is the impact of this chimeric effect? It depends on how well our DNA gets along!

How does this affect the fetus in utero? The fetus may be affected by clotting issues. Depending on maternal health status s/he may be subject to a stronger or weaker immune system.

How does this affect the mother? Women are more likely than men to develop autoimmune disorders (pregnancy playing a role here), and those who bear male offspring are more likely than those who only have girls to have these disorders.

The maternal/fetal dance goes on….

Be Prepared for Birth!

Be Prepared for Birth!