Pre Natal Changes

During pregnancy, a female’s body undergoes a vast array of changes be it physiological or biochemical. Physiological refers to the way the body functions, which includes respiratory, hormonal and metabolic changes. Biomechanical means the way the body moves or its structures; changes associated with pregnancy relate to musculoskeletal features such as posture, joint stability and weight gain.

Pregnancy duration is split into 3 trimesters; Trimester 1 is 0-12 weeks, the second is 13-27 and the third and final is 28- 40 weeks. Within each trimester the changes that occur are all different, and each may vary between females too; it really is true when they say no 2 pregnancies are the same!

In relation to physical activity, the transformation of the body does NOT mean that women should stop exercising. Instead, it is actively encouraged and is actually beneficial to both mum and baby as recommended by experts such as American College of Obstetricians and Gynaecologists (https://www.acog.org/)

Instead, exercises should be modified, which can allow the mother to continue to be active, right up until the final stage (if she feels like it!). Certain exercises should be eliminated for safety of mother and the developing foetus, but there are plenty of ways to retain a base level of strength and overall fitness.

Being qualified in Pre and post natal exercise, I am able to safely and effectively create exercise programmes for each trimester, taking into account the changes seen.

Here are just some of the ways a female may experience alterations in her body and what implications this may have in terms of exercising.

1st Trimester 0-12 weeks

The hormone progesterone causes blood vessels to stretch, however the amount of blood in the body remains the same which can lead to INITIAL VASUCALR UNDERFILL. This can result in a drop in blood pressure causing DIZZINESS and FATIGUE. Caution should be taken when changing position quickly e.g lying on a mat/ bench and returning to standing

In order to cope with the growing foetus, there is an INCREASE IN BLOOD PLASMA to ensure the mothers organs receive an adequate supply of blood.

This can lead to DILUTIONAL ANEMIA resulting in tiredness due to red blood cells containing less oxygen; therefore don’t be surprised if you feel like you have little energy to exercise! Instead, simply lower the intensity of exercise and stick to things such as walking or the recumbent bike at the gym and have a longer warm up phase.

Another hormone, oestrogen, causes growth of breasts and uterus. These hormonal imbalances can cause NAUSEA and lead to a weight gain of around 3-5kg so exercise becomes harder. Again, simply lowering the intensity of exercise and sticking to low impact cardiovascular activity will help.

2nd Trimester 13-27 weeks

Thankfully, dizziness and nausea are reduced by the 20th week as blood volume of the female increases. However, BLOOD PRESSURE INCREASES to pump blood around body and to the foetus. This should be monitored and ensure a longer cool down is carried out to allow the body to return to normal.

The hormone RELAXIN increases from the 4th month to soften ligaments and joints in preparation for the growing foetus. In particular, areas around pelvis, abdomen and spine are affected so caution is needed when stretching and carrying out abduction exercises as irreversible changes can occur.

The uterus can grow up to 4 TIMES the size as 1st trimester resulting in discomfort when sitting or lying. Certain exercises can therefore be done standing instead such as a standing cable machine row as an alternative to the seated row. Th change in centre of gravity may cause an issue with balance so holding onto a chair for support may help. Additionally, a stability ball can be used instead to perform seated exercises. Strengthening of the PEVLIC FLOOR muscles here is also vital!

As the baby grows, prone exercises (lying face down) should be avoided to prevent injury to baby e.g lying hamstring curl machine, back extension and certain yoga poses or stretches. However, do not fear there are plenty of safe modifications that can be done to work the same muscle groups! Additionally eliminate SUPINE positions to prevent SUPINE HYPOTENSIVE SYDROME. When lying on your back, the weight of the uterus can compress the aorta and vena cava, restricting venous return of blood to the heart. If severe this can also reduce blood flow to the foetus resulting in hypoxia. Side lying postions can help to avoid the syndrome.. Again, I can offer safe alternative to lying exercises to ensure this doesn’t occur!

POSTURAL CHANGES will also occur with the weight of the baby and breaths meaning areas that particularly need strengthening are lower back and glutes and stretching of the chest.

3rd Trimester 28-40 weeks

In the final weeks of pregnancy, weight gain can be between 11-15kg! That is quite a considerable weight to be carrying around so additional free weights/ machine loads can be removed or reduced weights. Any cardio exercise should be very low impact and an even lower intensity.

Expansion of respiratory system occurs to provide the baby with oxygen, which can lead to shortness of breath so make sure nothing is physically too exerting!

Mums to be will also need a LONGER WARM UP and COOL DOWN to allow steady changes in heart rate, blood pressure and body temperature- don’t forget there is another almost fully developing human inside!

Due to the growing baby, separation and lengthening of the abdominal muscles takes place. Care is therefore needed when carrying out core exercises due to DIASTASIS RECTI. Core strength is still important and can continue but avoid strong ab curling exercises. Thankfully I can assist with safe alternatives to avoid any irreversible damage.

The weight of uterus can cause STRESS INCONTINENCE so those all important pelvic floor exercises need to be done ladies! I can explain and guide you through these too!

This is not an exhaustive list, but I have highlighted some of the key changes that occur during pregnancy. There are also a host of changes to consider in the post natal period too! If any pain or discomfort around the pubic, pelvic or lower back areas is felt exercise should stop immediately. Extreme dizziness, chest pain or vaginal bleeding are also signs exercise should cease. In this case always speak to her your Doctor or a female health specialist.

Each woman will vary to the extent of the alterations their body undergoes and her base level of fitness will be different too.This means each programme needs to be carefully considered and modified on an individual basis. Ultimately health and safety is paramount for both mother and baby.

So if you would like to continue with your physical activity but aren’t sure how to do so, get in touch for more information so I can help you have a happy, healthy pregnancy.

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