Your body undergoes numerous physiological and biomechanical changes throughout the nine-month period of your pregnancy.


During the first trimester, most expectant mums experience vascular under fill, which occurs when the blood vessels become enlarged to supply sufficient oxygen to your baby, but your blood volume hasn’t changed. This effectively means blood flows more slowly around your body but your heart, at rest, is working 40% harder! This leads to nausea, a racing pulse, fatigue and dizziness.

During your second trimester, your body acknowledges these changes and releases a hormone to increase the blood volume – hence your morning sickness hopefully disappears!

Listen to your body. Don’t train if you’re feeling tired!

Body Temperature

You will probably notice that your core body temperature increases which is normal – however it is important that you keep an eye on this as, if it raises above 38C, it can indicate an infection and it’s worth seeking medical advice. If it is above 39C, call your doctor or midwife immediately.

Respiratory System

During pregnancy, the amount of air going in and out of your lungs increases by nearly 50% as each breath has a greater volume of air and you take more breaths. However, in your second trimester you may find it harder to take deep breaths, as your baby grows and pushes on your diaphragm.

Weight gain

Firstly, remember this is NORMAL! The following table shows the average healthy weight gain you can expect during pregnancy. Find out more about weight in pregnancy.

By completing exercise programmes, such as pregnancy Pilates, you will strengthen your core, and reduce the pressure extra weight puts on your body, especially joints.

Normal 18.5 – 24.9 11.5 – 16 kgs 25 – 35 lbs
Overweight 25 – 29.9 7 – 11.5 kgs 15 – 25 lbs
Obese 30 + 5 – 9 kgs 11 – 20 lbs

Information provided by Fit 2 Drop

Content Disclaimer

The information contained above is provided for information purposes only. The contents of this article are not intended to amount to advice, and you should not rely on any of the contents of this article. Professional advice should be obtained before taking or refraining from taking any action as a result of the contents of this article. New Life Classes disclaims all liability and responsibility arising from any reliance placed on any of the contents of this article.