Exercise during pregnancy

Sylvia has been a qualified midwife since 1974 and lectures locally, nationally and internationally on exercise during pregnancy. She is the Midwifery Adviser to London Central YMCA’s Pregnancy and Postnatal Fitness Video and has lectured at the International Congress of Midwives in Kobe, Japan and Vancouver in Canada. She took the Final Ante and Postnatal Specialist Module to Southern Ireland and lectured to fitness instructors for London Central YMCA. She was invited to participate and act as adviser on the Desmond Morris Video ‘Baby Watching’ and has lectured extensively in Norway, Japan, Canada and the Philippines.

The massive rise in interest in health related fitness has posed questions for pregnant women and professional carers alike. Many young women of child-bearing age are actively involved in contact sports (hockey, netball etc), participate in circuit training using weights to work out different parts of the body on stationary work benches, or attend ‘aerobics’ classes. A misleading term as ‘aerobic’, meaning with oxygen, should be just part of a well constructed fitness class that also includes a thorough warm up session, components to work on muscular strength and endurance, a section on stretch to develop flexibility in order to minimise potential injury and a cool down section at the end of the class. They may wish to carry on horse riding, continue with an advanced ‘step class’ or carry on cycling or jogging thirty miles a week. When pregnant women ask the question ‘can I continue?’ or motivated pregnant non exercisers want to do something that is safe, but have never exercised before, how, professionally, should we advise them? What is safe, or controversial, and researched?

How should exercise programmes be modified to ensure safety of the fetus and developing baby, and why?

In the first trimester (three months) of pregnancy one of the pregnancy hormones (relaxin) influences ligaments and supportive soft tissue. It softens them, thereby reducing stability of joints throughout the body. Obstetrically this is desirable, as a little more ‘give’ within the joints of the pelvic girdle allows more room for manoeuvring when the baby enters the pelvic girdle, engages and settles into the delivery position (usually head down). The increase of body weight, increasing lordosis (extra curvature of the lumbar spine) and change in centre of gravity all produce more stress for joints around the body. Any exercise must take into account the increased dangers to joints, especially in the pelvic girdle and spine. There should be no impact during exercise regimes, no jumping up and down where the impact would be transmitted through the joints and momentum of increased body mass would make it much more difficult to control direction and pace of movement. Relaxin hormone also affects the ‘stretch’ part of a fitness class.

In the non-pregnant exercise participants, emphasis is laid on taking a joint beyond its normal range of movement in order to stretch the attached muscle. These manoeuvres promote flexibility around a joint and decrease the likelihood of injury during normal everyday activities, and in any particular sport. The unwary can exploit relaxin hormone effect and potentially destabilise joints even more. As ligaments have a poor blood supply it may be months before the ligament returns to its pre- stretched normal length and gives joint stability once more. Although relaxin hormone is produced by the corpus luteum (on the ovary) from just 2 weeks’ gestation and then by the placental unit from 8-10 weeks’ gestation, the effects linger on post-natally from 3-5 months in the body, even though the placental production unit was delivered after the baby. Therefore, post-natal classes should be structured with the effects of relaxin hormone in mind, that is minimal impact, maintenance stretch techniques and emphasis on pelvic floor exercise and abdominal work adaptations.

As pregnancy progresses, increased weight (three stone or more for the average pregnant women) enlarging girth and continually adapting centre of gravity changes contribute to the pregnant women becoming more clumsy and less coordinated. The rate and pace at which she moves and time given to change direction are important considerations when planning an aerobic component performed to music and choreographed or planned by the exercise teacher.

The American College of Obstetricians and Gynaecologists Guidelines for Exercise during Pregnancy and Postpartum, state that maternal heartbeat should not exceed 140 beats per minute and strenuous exercise activities should not exceed 15 minutes duration. Research suggests that there may be a shunt of blood away from the uterus and its contents in order to supply oxygen to larger muscle groups demanding more oxygen during aerobic work leg the quadriceps or group of thigh muscles). Deep flexing or extension of joints should be avoided because of connective tissue or ligament laxity caused by relaxin. Also all ballistic (jerky) movements should be avoided. No exercise should be performed in the supine position after the fourth month of pregnancy.

The following conditions may contraindicate vigorous physical activity. These are taken from the American College of Obstetricians and Gynaecologists Guidelines:

  • High Blood Pressure
  • Anaemia or other blood disorders
  • Thyroid disease
  • Diabetes
  • Cardiac Arrhythmia or palpitations
  • History of precipitous labour
  • Intra Uterine growth retardation (smaller growth than expected during pregnancy)
  • Bleeding during pregnancy
  • Breech presentation during the last 3 months of pregnancy
  • Excessive obesity
  • Extreme underweight
  • History of 3 or more spontaneous miscarriages
  • Ruptured membranes (‘waters’ broken or draining)
  • Premature labour
  • Diagnosed multiple pregnancy (twins, triplets)
  • Incompetent cervix or neck of womb
  • Diagnosis of placenta praevia
  • Diagnosis of cardiac disease

Any of the following symptoms and signs should indicate the woman to stop exercising and seek advice from her midwife or doctor:

  • Pain
  • Bleeding
  • Dizziness
  • Shortness of breath
  • Palpitations
  • Faintness
  • Rapid pulse/resting
  • Back pain
  • Pubic pain
  • Difficulty walking

There are inherent benefits in exercising during pregnancy by maintaining muscle tone, strength and endurance, and protecting against back pain. Positive effects are noted in the improvement of mood and self image. In the postpartum or post delivery period, potential back pain and injury remain a significant problem for many women, as the daily care of a young infant involves repeated bending, lifting and carrying. Of great benefit would be an exercise programme that incorporated back, leg and abdominal strengthening exercises as well as utilising the pelvic tilt and pelvic floor exercises.

What are the benefits of exercising the whole body in a structured, specific way rather than targeting just the pelvis or ankles or abdominal corset?

In order to adapt to her changing shape and to help her cope with the demands of everyday living, a comprehensive exercise programme for the pregnant woman should include instruction on postural change and the how’s and why’s of achieving correct posture.

Any muscle groups that will help her achieve this more successfully should be strengthened with appropriate exercises. For example, strengthening all of the different muscle groups in the legs will help her to bend her knees, and not her back, when bending, picking up and lifting. Using the strength of quadriceps, hamstrings, gastrocnemius muscle groups will place less stress on her back and pelvis. Round shoulders are more common in the pregnant woman, related to increase in breast size and weight and caused by changes in centre of gravity. Shoulder retractions (contraction of trapezius muscle in between shoulder blades) will not only help strengthen the upper back but also help to improve posture and stance.

Aerobic work should be low impact, about 15 minutes duration and should not raise the pulse rate higher than 140 beats per minute. This immediately creates a problem for most fitness teachers as their aerobic sections or step classes are usually much longer than this. Aerobic work for the pregnant woman should be viewed as ‘maintenance’ work and not be pursued as an attempt to become more cardiovascular fitter, as you would normally expect for a class aimed at the general public.

This dilemma poses the question of whether a pregnant woman is safe exercising in a class that is not specifically structured for the pregnant woman. The section of an exercise class that aims to improve muscular strength and endurance aimed at ‘working out’ specific muscle groups around the body should be adopted accordingly. Particular attention should be placed on body position, technique, number of repetitions (pregnant women tire more easily), alternatives and reducing work load as pregnancy progresses. Press-ups performed on the floor during the first trimester may need to be performed standing against a wall in the third trimester, or much sooner if carpal tunnel syndrome (tingling and numbness in hands and fingers) is present. The benefits of exercise during pregnancy are now being recognised and highlighted by a number of researchers.

The main objectives of ante and postnatal exercise classes should be:
to increase the pregnant woman’s awareness and body control and help promote correct posture, and to
maintain and promote circulation around the body. Specific exercises relating to pregnancy, ie pelvic floor contusions, exercising pectorals to help support increased breast tissue should be incorporated into their exercise routines.

Attention should be paid to tailoring the intensity of exercise to different stages of ante and postnatal work. A regular exercise programme 2-3 times per week specifically tailored to take into account the limitations of pregnancy helps in maintaining mobility and teaching body awareness. Complaints about minor ailments of pregnancy ie varicose veins, haemorrhoids and morning sickness are said to be reported less by regularly exercising pregnant women, who also report improved sleep patterns, particularly within the third trimester (last three months of pregnancy)

Any pregnant woman who attends any exercise class should be screened by the teacher before participation. Pertinent questions should include:

  • highlighting any problems in past pregnancies, present pregnancy or in conceiving.
  • Are there any joint, muscle, bone injuries, disc problems, back injuries?
  • Are there any medical problems present, eg diabetes, epilepsy, heart disease, high blood pressure?
  • Are any medications being taken at present?

If the answer to any of these questions is yes, then a more detailed history should be elicited to ascertain if participation is advisable. A typical structural outline of an exercise to music class, where the teacher plans or choreographs dance-like steps in between specific body movements would be as follows:

The class would start with a ‘warm up’ section. Major joints are mobilised and taken through a normal range of movement. Larger steps and body movements are introduced to slowly raise the pulse a little and improve blood flow to major muscle groups. The last part of the warm up would be short held static stretches to major muscle groups around the body, as pre-warmed stretched muscles contract and relax more efficiently. Warm up is vital in all exercise classes and reduces the risk of injury as well as preparing the body for the work that is to follow.

The aerobic section of the class is aimed at increasing pulse rates by using more dynamic, longer body movements by working major muscle groups, eg quadriceps gluteals in order to improve the efficiency of the cardiovascular system (heart an lungs). Following this, specific muscle groups around the body would be targeted and exercised. Following the ‘work’ part of the class would be a cool down section – exercised muscle groups would be gently stretched to release tension within them, followed by a relaxation session at the end of the class.

All parts of the class should be structured specifically to take into account the physiological changes induced by pregnancy and the limitations that they impose, thus very specific training in ante and postnatal exercise should be mandatory for the exercise teacher working in this area of expertise.

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