2016 evidence summary from the IOC: PART ! PREGNANCY

Exercise and pregnancy in recreational and elite athletes:

First Trimester : Key points Hormones are released by corpus luteum, placenta and

developing embryo – this cascade then regulates implantation, fetal- placental growth and development

Consideration of adaptations maternal, placental adaptations, and fetal adaptations will all steadily take place through the trimesters

Higher levels of physical activity and exercise consistently show reduce levels of depression and anxiety within general population : moderate strength evidence

Consider that hormonal changes contribute to muscle fibre change from oxidative to glycolytic : weak strength evidence

Nausea! HG – monitor electrolyte balance and 1% rising levels of HCG or Oestrogen. Can be other DD so always check with GP Vit B status as well as RED.

First Trimester Mood changes : factors to consider are weight

gain. Lethargy, social factors, exercise and endorphin changes, dietary changes,

Fatigue ; an overwhelming sustained sense of exhaustion and decreased capacity for work. –check GP nutritional status, support at home, anaemia possibilities.

After 5th week – CV system is substantially changed. Oestrogen mediated changes cause reduction in vascular tone, increase in venous captitance … hence increase risk of varicose veins.

15-20 bpm increase in resting HR, Stroke volume increases by 10% then progressive blood volume increase (so all these factors can increase throughout)

First Trimester Increase in respiratory sensitivity to carbon

dioxide (this is to prevent fetal acidosis) all the CV changes protect against significant collection in CO2

Maternal blood glucose is the primary substrate for feto-placental growth. * Deficits in glucose need to be replaced efficiently

Hormonal management of glucose encourages adipose development for use in the later stages of pregnancy.

• 90kcal / day increase (with mean GWG of 12 kg)

First Trimester • 1st Trimester thermoregulation at its most

sensitive – it steadily improves over the pregnancy.

• Fetal neural tube development is 35-42 days after last menstrual period – this is the risk period for core temperature change after this temperature regulation is less risky.

• Relaxin ; no fixed evidence that tests load risk / flexibility change but consider the athletes baseline flexibility as part of the assessment

Second Trimester Stated that postural changes

contribute to reduction in postural balance – pregnant women are 2-3 times more likely to floor

Exercising in pregnancy at 60-70% VO2 max in a controlled environment for more than 60mins does not raise core temperature levels

There are still no studies that measruethe temp changes in endurance athletes (> 60 mins, changes in ambient temperatures)

Centre of gravity / load changes

Second Trimester Mood; Generally known as the best trimester

for social support reasons, anxiety reasons (20 week scan over) and stabilisation of hormonal systems.

* With this in mind if patients are struggling into the seconds trimester this is more of a flag to pursue advice.

Diaphragm ; Rib expansion, Uterus pressure, reduction in reserve volume. This can create breathlessness and is normal for this stage in pregnancy.

Second trimester Submaximal steady state exercise has been

shown to reduce the perception of breathlessness and respiratory effort. Because the adaptations are still designed to increase oxygen uptake and transport efficiency relative to body mass changes.

SUPINE positioning! Compression of inferior vena cave – which can cause hypotension 10-20% but research has shown this can be the same for other prolonged positions (standing, sitting, as well as supine)

Second Trimester Uterine blood flow loss in supine position during

exercises is 50% of the changes seen in resting supine position.

Nutritional requirements start to increase – breast growth, adipose layering, amniotic fluid increase, placenta growth, increase blood volume.

287 kcal/ day

Second Trimester Effect of extra weight on intra-abdominal

pressure and therefore pelvic floor stress (Extra weight – even more reason to start PF training earlier)

See link for PFTE.

Third Trimester Depends on size of baby / strength of mum 5-6 months

(increased lordosis, anterior cervical load, and breast enlargement that changes thoracic loading)

PGP / LBP due to increase in load 50% - overload of ligament, ineffective load transfer, spinal overload, postural fatigue

Increased Lordosis – increased stress on Psoas / Lumbar facet joints / rib angle change CVJ congestion

Anterior tilt increases by 5%, increase in hip flexion during stance phase, loss of extension stance phase, and therefore loss of toe off phase.

Third Trimester ** 3-5 / week high impact exercise showed less

incidence of LBP

PFD ; sex / emptying / abnormal use / urinary and faecal - most common is involuntary leakage (De Lancy et al complete life model of PFD)

Diastasis RA – no consensus for measurement –finger breaths or US MM (> 3 fingers ? significant)

GWG consistent weight gain – but overall to be considered

Third Trimester The feto-placental unit can use as much as 30-

50% of available maternal glucose in 3rd trimester.

Reduced stride length, increased heel strike, increased joint reaction force.

Weight gain 10-12 kg normal weight gain for GWG pregnancy – highest in 2nd Tri (0.5kg per week) nutritional monitoring

466 kcal/day

Third Trimester Oedema – extra fluid retention -once cleared /

advised of risk factors PE and GD, then helpful to start exercise program, effleurage, hydrotherapy

Obstructive pressure of the uterus on vena cava – this is flag that supine exercise is not appropriate for this patient group

Third Trimester: Exercise Risks

> 90% of VO2 max has shown fetal bracycardia

Target HR need to be decided on an individual basis recommendations in recreational athletes will always be 60-70% only

Target zones need to determined from start of pregnancy when dealing with elite athlete you cannot use non-pregnant VO2 max values.

Third Trimester: Exercise Risk Due changes in respiratory capacity to expire C02 earlier

pregnant RER might be seen to be more efficient (but is the failure rate faster and more extreme)

RPE is useful measure for monitoring exercise intensity

ALTITUDE – no fixed results – but 7 healthy pregnancies test at > 6000ft (but this is not exercising) the concern is inability to maintain effective fetal oxygenation.

WEIGHT TRAINING _ safe and positive results light –moderate strength training with increase lumbar endurance

RiSKS are rapid increase in BP and increased intra abdominal pressure

Third Trimester: Common Conditions

Nausea – Hyperemesis gravidarum, severe and persistent vomiting > 5% pre pregnancy weight, dehydration and electrolyte imbalance

Ensure monitor RED

Preeclampsia – may reduce exercise capabilities and increase injury risk base on inactivity

Gestational Diabetes – weight gain increases injury risk

Oedema – effleurage / massage can help

Varicose Veins

Third Trimester: Common conditions Hypertensive disorders from 1-3rd tri – effecting 2-7& of pregnancies,

Here are the risk factors

Previous Hx

Maternal Age > 40

Assisted Repro

Obesity or excess weight gain

• Mother or Sister

• Heritable thrombophillas

• Type 1 Diabetes

• Renal disease

• Mulitifetal gestation

• Cocaine / Amp use ** There are studies that link exercise to reduced risk.

Monitoring Regular checks of weight, BP and urine are

meaningful for identification of many of these issues.

Athletes need to ensure regular attendance to midwife appointments.

Reference Link to Full Text https://bjsm.bmj.com/content/52/17/1080