Sophia McDermott Drysdale: A Trainer’s Guide to Pregnant Clients

There’s a long-held misconception that pregnant women shouldn’t work out. As a trainer and a coach, I am constantly receiving feedback from my pregnant clients—health professionals are telling them to stop training in their sports or to stop their workouts.

In the majority of circumstances, this doesn’t make sense to me because it doesn’t make sense with what we know about pregnancy. If your client is an athlete or is currently working out, I believe that stopping training can be more detrimental to their health and the health of the baby than the possibility of other risks that may occur during training or exercise.

Maybe the health professionals are worried that we don’t have enough information?


Of course there is information that all trainers need to be aware of in all stages of pregnancy, and during the later stages of pregnancy, there are some exercises that are absolutely unsafe.

Much of it comes down to common sense and the mother’s instinctive knowledge of what feels right for her and her body.

Listen to her, apply what you know and modify training and exercise programs; once trainers understand exactly what is going on inside the mother’s body they can instruct and guide accordingly.

Assuming that your client is healthy and has no complications (and this is a big assumption: listen to the information that they convey from their healthcare provider, but also give them the knowledge to advocate for themselves when they return to the provider), with knowledge and clear communication of your client’s needs a safe and effective program can be continued and the client can continue to receive all the benefits of exercise for herself and her baby.

It is useful to have the knowledge and experience to be able to safely train expectant mothers, since most women at some stage in their lives will become pregnant. This is especially important if you have long-term clients who wish to continue to train during this exciting, yet challenging, time to ensure that they remain as physically fit and healthy as possible.

Changes during pregnancy
This article is a starting point; it lists many of the changes that occur in a woman’s body during pregnancy and birth. It is vitally important to understand all of the hormonal and physiological changes that occur in order to select stage-appropriate exercises for the client during pregnancy and postpartum. It is also important to know which muscles and ligaments become weakened and stretched, in order to rehabilitate and restore proper functional strength and mobility. This is especially true for athletes who desire to return to their respective sports with heightened intensity but don’t want to risk compounding their muscle imbalance and instability.

Hormonal Changes
The initial changes during pregnancy are hormonal. Even if the expectant mother does not show the physical signs of pregnancy, such as a baby bump, the hormonal changes have a significant effect on the mother’s body and as a trainer it is important to know just how profoundly they affect her physically, mentally, emotionally and physiologically.

Estrogen and progesterone are the main hormones that are produced which helps to grow and nourish the baby and the placenta and create changes in the mother’s body. Serum estradiol levels are 30 to 40 times higher and progesterone levels are 20 times higher in the third trimester of pregnancy than peak levels during a woman’s normal menstrual cycle. (1)

A woman will produce more estrogen and progesterone during one pregnancy than during her entire lifetime without a pregnancy and all these changes can cause extreme fatigue, particularly in the first trimester when the body is working hard to adjust.

Another hormone called human chorionic gonadotropin (hCG), which is produced at higher levels during the first trimester than at any other time during pregnancy, is thought to be the culprit behind morning sickness. This is the hormone that is detected in a pregnancy test. It is important to know that while training a newly expectant mother, she may be experiencing extreme fatigue and nausea.

Changes to Blood Volume and the Cardiovascular System
Blood volume increases progressively during pregnancy and continues until the last few weeks before birth. The blood volume of plasma increases by a whopping 40-50% and red blood cell mass increases by almost 20%. These changes can actually make the mother feel very strong and have better endurance in the earlier stages of pregnancy while the fetus is still small.

Even though the mother may feel stronger, her heart rate increases up to 15% and is working 40% harder to pump more blood at each beat to circulate to the uterus during pregnancy. (2) Additionally, as the uterus enlarges and compresses the diaphragm, it becomes more and more difficult for expectant mothers to take deep breaths. This difficulty is only compounded by the fact that pregnant women require more oxygen so their breathing rate increases as well as the amount of air they take in with each breath.

Training a pregnant client is a situation that calls for constant monitoring of the level of physical exertion, heart rate and breathing rate while exercising.


The changes in hormones and blood volume also affect blood pressure. Progesterone causes the walls of the blood vessels to loosen causing low blood pressure.  Many women, especially in the earlier stages of pregnancy, may experience head spins, dizziness and may even faint when standing up too quickly. At all stages of pregnancy, it is important to change levels slowly.

Increase in Body Temperature
An increase in basal body temperature is one of the first signs of pregnancy, and a slightly higher core temperature is maintained throughout the duration of pregnancy.  It is absolutely crucial that your clients do not overheat during a workout, since the fetus does not have the apparatus to cool itself down, especially in the early stages.

The first three months are the most important months for the development of the baby because that is when all the vital organs, brain and spinal column are formed. Overheating in the first trimester can lead to birth defects.  Additionally, overheating and dehydration can lead to premature contractions. Dehydration causes blood volume to decrease, which increases the level of oxytocin (the hormone responsible for contractions and preterm labor.) (3)

Train your client in a cool environment and make sure she maintains hydration.


Weight gain and fluid retention
According to the American Congress of Obstetrician and Gynecology, the recommended overall weight gain is 31-50 pounds for a woman of normal BMI and a weight increase of 15-20 pounds for overweight women. (4) This includes the weight of the baby, placenta, amniotic fluid, increased blood volume and extracellular fluids. This additional fluid retention is necessary to help cushion the baby and the joints of the pelvis, knees and ankles that support the baby weight. The increased fluid plays an important role in softening the joints in the pelvis that need to widen for birth.

At least 25% of the overall weight gained during pregnancy is due to additional fluids alone. (5)

It is important to know what contributes to the added weight gain so that body fat levels can be monitored. Body fat, while crucial to support the growth of the baby and to produce the milk to feed the baby once it is born, should not contribute to the overall weight gain.

Water retention can cause swelling particularly in the lower limbs—especially the ankles and feet. This is particularly noticeable in women who have been standing for long periods of time. The swelling can become very uncomfortable and in some cases painful. Additionally, the overall weight gain can take its toll on the lower back and joints and can decrease mobility.

The mother’s metabolism increases during pregnancy and her energy demands become higher. Many pregnant women express symptoms of hypoglycemia or low blood sugar. Be watchful for signs of your clients feeling lethargic or faint and/or displaying decreased levels of concentration or slurring words.

The effects of hypoglycemia can come on suddenly with little or no warning, so it is important to keep track of the times of your client’s meals in relation to her workouts, even if you do not normally track nutrition.

Structural Changes in the Pelvis
As the baby grows during pregnancy, there is increased pressure on the mother’s lower back, hips and pelvis. Aside from the added weight of the baby, the placenta and the amniotic fluid, there is a shift in the weight distribution and the center of gravity. As the baby belly sticks out from the front this shift causes the pelvis to tilt forward, tightening the hip flexors and conversely stretching and weakening both the glutes and hamstrings. This imbalance can cause lower back pressure and pain.


During the later stages of pregnancy many women experience what is known as symphysis pubis dysfunction. This is caused by progesterone and the hormone relaxin which loosens the ligaments and joints in the pelvis. (6) The pelvis consists of several bones, including the sacrum, coccyx (tail bone), and the left and right coxal (hip) bones. The bones connect at the front by the pubis symphysis joint and at the back by the sacroiliac joints. Relaxin loosens up the cartilage in the joints, which separate and widen the pelvis to allow for the baby to go through the birth canal.

Many women experience quite pronounced pain in the front of the pelvis when they perform side-stepping motions and single-leg motions such is walking up stairs. Pain in the SI joint can also be felt when standing for long periods of time.

While this hormone is critical for a successful birth, it also can make exercise more difficult since relaxin affects the entire body. Pregnant women may be at greater risk for sprains and strains and instability in the hips because all of their ligaments are looser.

During birth, the ligaments deep inside the groin become stretched and weakened making it difficult for new mothers to perform hip adduction and hip extension after birth.  Severely stretched and separated abdominal muscles, an overused, tight lower back and weakened glutes also contribute to a lack of strength in the pelvis and core.

Diastis Recti
The abdominal wall, particularly the rectus abdominis, may begin to separate as the baby grows, creating the what is called the Diastasis Recti. I have found from my own personal experience, and from training other pregnant women, that the thicker and stronger the abdominal muscles are, the wider the gap tends to be. This is not painful per say but it does contribute to major weakness though the core. Abdominal and core exercises should be modified and decreased as the pregnancy continues.

Working with the Changes
You’ve just read a brief overview of the changes that occur in a woman’s body during pregnancy and birth, but remember, women are apt at adjusting. Life and exercise don’t usually need to be stopped since pregnancy and birth are actually an intrinsic part of a women’s life, not a stage where she is treated as if she has a sickness and should be put to bed rest for the next nine months (unless there is a specific medical reason, and in rare cases, there are).

With knowledge, common sense and clear communication, an effective training program can continue to be carried out right up until birth. Your client will feel stronger, more fit and more confident throughout her pregnancy. She will also be better equipped to deal with the birth and caring for her newborn if she is active throughout her pregnancy.


  1. Ovarian Hormones and Migraine Headache: By Vincent T. Martin, MD; Michael Behbehani, PhD
  2. Blood volume changes in normal pregnancy. October 1985
  3. Exercising During Pregnancy: The American Congress of Obstetricians and Gynecology. May 2016.
  4. Weight Gain During Pregnancy: The American Congress of Obstetricians and Gynecology. January 2013. HYPERLINK “”ring-Pregnancy
  5. Swelling During Pregnancy.
  6. Pregnancy Day By Day. Maggie Blott MD, 2009, New York. DK Publishing. Page 470

Look for future articles from Sophia that delve into exercises for pregnant clients to avoid and their healthy alternatives.

More from Sophia McDermott Drysdale at OTP:

Sophia McDermott Drysdale: 6 Reasons Why ALL Women Should Perform Resistance Training

More on training pregnant clients from OTP:
Training Through Pregnancy, Personal Training For New Mothers, How To Train A Pregnant Client

Galina Denzel: Training the Pregnant Client