Pregnancy Trimesters
Pregnancy is divided into three trimesters Each trimester lasts three months Dated in weeks from the first day of the last menstrual period
1st: Week 1 – Week 12 2nd: Week 13 – Week 24 3rd: Week 25 – Week 36
The physical effects of pregnancy are many and include:
Varicose veins and haemorrhoids may occur, particularly in the last trimester due to increasing pressure in the pelvis and therefore restricted venous return
Iron requirements increase
(Fluid leak - swelling of feet/ankles)
Cardiac input increases 30-50% from week 6 to about week 24
Cardiovascular WBC increase slightly
System
Blood volume increases; plasma by 50%, RBC by 25%. Haemoglobin may be lowered by dilution
BP usually drops (with a widening pulse pressure gap) but may return to normal in the third trimester
Pulse increases to 80-90bpm (Heart works harder to pump increased amount of blood around the body)
Hormones and placement of the foetus contribute to feelings of slight breathlessness or exertion, particularly through the third trimester. Breathlessness prior to this may be due to anaemia
Occasionally the ears and nose can become blocked (due to hormonal influence); this may effect balance
Swelling/fluid retention in ear canal, ear popping/clogged sensation Mucus membrane swollen Sensitive, continual stuffy nose
Enlarging uterus pushes up against diaphragm
RESPIRATORY SYSTEM
Tidal and minute volume, respiratory rate and oxygen consumption increase
Thoracic circumference increases by up to 10cm, further compromising the effectiveness of the diaphragm
Tidal – volume of air inspired and expired in a single breath during normal breathing. Minute – volume of air expelled from lungs per minute
Constipation: as the pregnancy progresses the effect of hormones in the body slows the transit of food through the digestive tract
Urinary output increases
Increased blood volume Uterus presses against bladder Hormones relax uterus
By relaxing the muscles of digestive tract
DIGESTIVE AND URINARY SYSTEMS Indigestion, belching and reflux may be more common due to compression of the stomach by the foetus
Heartburn (hormones also relax the sphincters of the stomach allowing some of the acidic stomach contents to irritate the oesophagus)
Uterus increases in size, pressing on stomach, increasing pressure
Increase thyroid function, often producing signs of hyperthyroidism, tachycardia, palpatations, excessive sweating and emotional instability
Skin pigment and increased breast size (they become hard and painful, from the first trimester onwards)
ENDOCRINE SYSTEM
Increased production of Melanin Alter the body's response to glucose, increasing the need for insulin (to ensure glucose levels dont rise to dangerous levels
Increase adrenal gland function (striae and ordema - fluid balance)
Emotions Leg cramps
Fatigue
Water retention
Impaired balance
GENERAL Pregnancy nausea
Poor sleep
Reduced mobility
Back pain Posture and gait change
BENEFITS OF EXERCISE 1. 2. 3. 4. 5. 6. 7. 8. 9.
Fitness for birth (potentially less time and fatigue in labour) and faster recovery Retain fitness levels Avoid excessive weight gain Reduce problems associated with water retention (swelling in hands and feet) Improved sleep pattern Increased energy levels Better digestive transit Improved posture Reduced back pain
CAUTIONS 1. Avoid the supine position from the second trimester onwards. The increasing weight of the foetus and placenta rests on the mother’s spine and may compress blood vessels supplying the placenta (and therefore foetus) and the mother leading to feeling of discomfort and light-headedness 2. Avoid rapid changes of direction 3. Rectus abdominus separation (cross arms to prevent) 4. Avoid raising blood pressure Avoid hand-held weights in classes or for cardio work Avoid isometrics Correct breathing patterns (out on exertion) 5. Avoid overheating – remember core temperature can increase without sweating 6. Stop exercise if any of the following occur: Dizziness Pallor (colour – red) Shortness of breath Palpitations Decreased foetal movement New or persistent uterine Contractions (anything you shouldn’t be feeling) Vaginal bleeding Rupture of membranes (e.g. waters break)
ABSOLUTE CONTRAINDICATIONS TO TRAINING History of:
Spontaneous miscarriage Ruptured membranes Premature labour Diagnosed multiple pregnancy (twins or more) Intrauterine growth retardation (smaller than expected foetus size) Incompetent cervix size (softer and more open than normal) Pregnancy-induced hypertension Venous thrombosis or pulmonary Cardiac valve disease Primary hypertension Maternal heart disease
RELATIVE CONTRAINDICATIONS
Hypertension Anaemia Thyroid disease Diabetes Extremely under or over weight Extremely sedentary (in-active) History of bleeding in a previous pregnancy Breech presentation in the third trimester
EXERCISE GUIDELINES Intensity Continue exercise within capabilities. It is sensible to step down the intensity, e.g. from high or intermediate intensity classes to a maintenance level. Keep the Heart Rate under 140 (guideline)
Beginners Non-weight bearing exercise is recommended, e.g. swimming, cycling and walking. A 20-30 minute session daily at a comfortable pace is a reasonable goal. Jogging would not be a suitable activity.
Previously Active Unless there are complications or a medical condition, most active women can continue to exercise, with the exception of contact sports, scuba diving and high altitudes.
Running If a woman has been running for some time prior to pregnancy, then its fine to continue to do so. It may be sensible to reduce the running time to 45 minutes or less, and to consider avoiding hills. As the pregnancy progresses, fast walking may be an alternative to running.
Weight Training May be continued if the woman has been performing this exercise prior to pregnancy. Lifting heavy weights should be avoided as the pregnancy progresses.
GENERAL GUIDELINES Temperature Control High core temperature is of some concern for pregnant clients, as the foetus is unable to regulate its heat by sweating. To avoid high core temperatures the following guides can be used:
Exercise in the coolest period of the day, avoid exercise in hot and humid conditions Avoid prolonged exercise, instead exercise in intervals of 15 minutes with breaks of 2-3 minutes to allow recovery Wear light loose clothing Stay well hydrated Avoid high intensity activity, the client should always be able to talk throughout the exercise Do not use saunas, steam rooms and hot tubs
Avoiding Injury Due to increasing levels of the hormone relaxin the pregnant clients ligaments become more flexible and therefore are less protective of the joints. To avoid injury follow these guidelines.
Choose low impact exercise (one foot always on the ground) Go down a level (for example intermediate to beginner) Aim for maintenance, not adaptation Foot wear should be supportive and appropriate to the activity Exercise on flat even surfaces Avoid full flexion or extension of joints Avoid excessive stretching (don’t take the stretch to the end limit)
Nutrition
Good nutrition Folic acid supplement Mid wife The caloric needs of a pregnant woman only really increases in the third trimester, and then only by about 250-300 calories per day (Eating for two is a myth!) In the early stages of pregnancy the body’s metabolism alters and slows, therefore using fewer calories.
All pregnant women should have regular appointments (monthly, increasing to weekly as the pregnancy progresses) with a midwife. The midwife monitors the maternal BP, weight and general health, and organizes various blood and urine tests and scans. He/she will also monitor the growth rate of the foetus (using the fundal height to estimate) and the HR of the foetus. The midwife will also inform the pregnant woman of her dietary requirements. In pregnancy the requirement for iron increases, particularly in the third trimester when blood levels drop again. It is common practice for all females to take a folic acid supplement prior to conception, and if not to start taking one as soon as conception is suspected or confirmed. This helps to reduce the risk of neural tube defects (for example spina bifida) which if they are going to happen occur in the first few days and weeks of pregnancy. The midwife will advise on the need (or not) for other supplementation throughout the pregnancy. The caloric need of a pregnant woman only really increases in the third trimester, and then only by about 250-300 calories per day (eating for two is a myth!). This is because in the early stages of pregnancy the body’s metabolism alters and slows, therefore using fewer calories.
EXERCISE AFTER CHILD BIRTH It is important to recognise the enormous physical and mental upheaval having a child is. The effects of hormones, stress, fatigue and physical demand can have an exhausting effect on the mother (and father!). In the early days and weeks post-birth, the mother should be supported in her choices and not made to feel she should suddenly spring back to her pre-pregnancy figure. The messages promoted by magazines are non-productive and place unnecessary pressure on the mother; at this stage of prime importance is her recovery and care of her baby. However, when possible it is desirable to start exercising fairly soon after the birth. Gentle sit-ups and pelvic floor exercises (helping to restore normal tone to the muscles that have been stressed by the pregnancy and birth) can commence as soon as the birth is over, providing the mother is not too sore, and has not had a caesarean section, and will help reduce stress incontinence. Gradual resumption of moderate exercise can begin as soon as the mother feels ready, usually about six weeks post birth. Hormone levels can take at least six months to return to normal levels, and it is considered normal for the body to take 12 months to return to normal.
SUMMARY Pregnancy is a wonderful thing and women need not fear exercise as staying fit and active is a good thing during and after pregnancy. However, considerations relate to both the expecting mum and unborn child. For this reason it is important to be cautious. Where contraindications do not limit exercise, both cardiovascular and resistance training have many functional benefits. Exercise is especially important after clearance is granted after birth.