Exploring Pregnancy Stages and Changes

16 Feb ‘24
7 min
Editorial Board OpenUp
Reviewed by lifestyle expert Aäron Spapens

Pregnancy is a journey of growth, not just for the new life blossoming within you, but for you as well. It’s a time when your body showcases its strength and adaptability, with physical transformations being just the tip of the iceberg. Beneath the surface, a series of physiological changes occur—nature’s way of ensuring both you and your baby thrive throughout this beautiful journey.


What exactly happens in your body during the different trimesters? And after your pregnancy, in the postpartum period? Let’s explore the physical and mental evolutions you can anticipate, complemented by practical advice to navigate these changes smoothly.

In this article, we will explore: 

• The first trimester

The second trimester

• The third trimester

• After pregnancy: postpartum


1. The first trimester


In the first three months, your body goes through the most significant changes. This is due to the human chorionic gonadotropin hormone (HCG), a hormone that puts your body into ‘pregnancy mode’. It causes the ovaries to pause maturing new eggs and the little pile of cells that make up your baby now stays in the womb. Unfortunately, the hCG hormone is also the culprit of morning sickness.



🤰🏻What can you expect?


• Frequent urination: More blood passes through your kidneys to carry away extra waste products. Together with the growing uterus that can press on your bladder, this makes you have to urinate more often. Tip: put a measuring cup next to your bed so won’t have to run to the toilet at night.


• Changes in breast size and/or sensations: Your breasts may increase in size in a short time and may feel tight. On average, breasts grow about one to two cup sizes during pregnancy. Your mammary glands are preparing to produce milk by the hormone prolactin.  As a result, your nipple hollows and grows, which is mother nature’s way of giving your baby more grip on the nipple. They may also become darker in colour, so your skin is more visible to your baby as well as firmer (and thus better protected from vigorous sucking during breastfeeding).



2. The second trimester


During the second trimester, your body is busy making room for your baby. At the same time, new changes may pop up for the first time as your belly continues to grow and the levels of pregnancy hormones in your body keep rising.




🤰🏽 What can you expect?


Progesterone acts on the muscles, ligaments and joints causing them to become slacker and more flexible. This hormonal effect is thought to be responsible for some of the stitch-like pains that some women experience in the lower part of the tummy and in some cases this can be quite severe. The same hormones can be responsible for constipation during pregnancy; this can also cause abdominal pain. This sagging of your body can also cause discomfort, such as constipation, varicose veins, fluid retention, heartburn and pelvic pain. To help, eat a balanced diet with high-fibre foods (lots of fruit and vegetables!) drink enough fluids, exercise regularly and go to the toilet immediately if you feel an urge.


🩸 Your blood volume increases


Because you are now sharing your blood with the growing foetus, your blood volume increases by 40 to 50 per cent. This is your body’s way of maintaining the right blood pressure. You also build up a reserve in advance for the blood you will soon lose during labour. Unlike your increasing blood volume, your red blood cell count increases by only 20 to 30 per cent, diluting your blood. Consequently, some women may develop ‘dilution’ anaemia.



3. The third trimester


Your heart is now pumping for two. The volume of blood your heart pumps through your body per minute increases by about 40 per cent. You may notice your heart beating firmer and faster (±15 beats per minute more). Don’t worry, after your delivery this returns to your ‘normal’ level.


The placenta produces the hormone human placental lactogen (hPL). This stimulates your fat burning, so you get more energy from fats, leaving enough carbohydrates and proteins for your baby.




🤰 What can you expect?


During pregnancy, your body may react differently to insulin, increasing the risk of gestational diabetes.  Although it can happen at any stage of pregnancy, it is more common in the third trimester. It happens when your body cannot produce enough insulin – a hormone that helps control blood sugar levels – to meet your extra needs in pregnancy.


If you already had reduced sensitivity to insulin before pregnancy, due to your lifestyle or genetic factors, for example, it is important to be extra vigilant. It is important to know that adopting unhealthy habits during pregnancy can further increase this risk. Fortunately, gestational diabetes usually disappears after delivery, but it does indicate that you may have a higher risk of diabetes in the future. So it is important to be aware of these risks so that you can make healthy choices for you and your baby.

Nausea and/or dizziness


During the third trimester, your enlarged uterus presses on the large blood vessels and organs in your abdomen. This can make you dizzy or nauseous if you lie on your back for a long time. 


Don’t worry about passing out if you accidentally lie on your back while sleeping. Your body senses this and automatically changes its position. When lying on your side, you can support your stomach with an extra pillow. And a pillow between your knees will ease your pelvis.

Back strain


Your growing belly can cause you to walk backwards, putting an extra load on your back. If you experience this, try the following tips or visit a physiotherapist.


1. Pay attention to your posture 


•  Stand quietly and place your feet hip-width apart.

•  Distribute your weight over both feet. Perhaps move back and forth a few times to get a good feel for where you are leaning your weight.

•  Keep your knees slightly bent.

•  Now tilt your pelvis to a neutral lower back position.

•  Let your arms hang relaxed. Rotate your shoulders in a few circles. Eventually, your shoulders may hang low and slightly back.


2. Stay active


Your growing belly puts more stress on your back muscles and stretches your abdominal muscles. This creates an imbalance between the abdominal and back muscles. Therefore, take care of your abdominal, pelvic floor and back muscles during your pregnancy. Especially during the first two semesters regarding abdominal muscles and during the third semester regarding pelvic floor and back muscles:


•  Do relaxing exercises, such as pelvic tilts on a sit-up ball (forward and backward, sideways, circles). 

•  Wear sturdy, comfortable shoes.

•  When standing up from lying down, come onto your side first, then use your hands to push yourself up.

•  Lift from your knees.

A pregnancy physiotherapist and/or a pregnancy trainer (pre/postnatal trainer) can further help with targeted, appropriate exercises for you.

Fun fact 💡Did you know that pregnant women’s feet grow on average half a shoe size during pregnancy? This is due to the changed posture, slackening of ligaments and weight gain. And yep, that bigger size is permanent.

Your brain during and after pregnancy 


During pregnancy, the structure of your brain changes, especially in areas with social functions. A natural and extraordinary process, all to get you ready for parenthood! The changes persist for at least 2 years after birth.


1. Your emotional intelligence strengthens


Brain scans show that some areas for emotion processing change, such as the amygdala. For example, it turns out that you read emotions from faces faster, which contributes to bonding with your baby. 


You also detect danger better and strengthen your senses, such as your sense of smell. All to better protect the baby.


2. Slow waves dominate


Moreover, the waves that are dominant in your brain change. Your brain can go fast and slow: this is measured by brain waves. The fast waves (also called the beta waves) are great for organising and analysing from your head. 


But you might be familiar with the term ‘’mom brain’’: in fact, some studies show that the brain of pregnant women is more likely to be in the slower waves (the alpha waves). These are the waves for sensing and which are active when you are relaxed or daydreaming.


 • You may be more forgetful or have trouble concentrating. 

 • There is more room for input from your senses and many women feel more connected to their bodies.

 • You may notice that you can express yourself more easily with creative activities, such as making art or writing.

Tip 💆 Notice what is going on in your body and head. It helps to talk to others about your changing body, emotions, worries and thoughts – such as your partner or a close friend. Let those around you know what you need, or what they can help you with.

Postpartum changes


Postpartum is the period after you give birth – also known as the maternity period (6 weeks) or time for de-pregnancy (roughly 9 months). Sometimes this phase goes off without a hitch, and sometimes there are a few more bumps in the road. Why is this? 


You are going through one of the biggest hormone changes you can go through as a human being. Together with the disruption of your day and night rhythm and the change from woman* to parent, this can make the maternity period an intense one. Special, but intense.


👩🏽‍🍼 What can you expect?


All sorts of things can happen during this period. You may have had a hard labour, have little social support or make high demands on yourself. You may also have suffered certain nutritional deficiencies, as many nutrients are passed on to the baby during pregnancy and/or breastfeeding. 


This can cause discomfort, such as fatigue, forgetfulness, feeling agitated and easily overstimulated. You might feel insecure, frustrated or anxious about this new chapter in your life. 


What can you do?


It helps to prioritise rest (although this is often very difficult) and make sure you eat comforting and nutritious food, stay connected to social support and allow yourself space to process your emotions.  The transition to parenthood can bring up all kinds of feelings and that’s okay. 


👉 Want to discuss tips for your situation with one of our lifestyle experts, including female health experts? Book a 1-on-1 session. 

* For the readability of this article, we refer to ‘woman’ instead of ‘biological female body’. But whether you identify as a woman or not – our tips for the changes in your body apply to every pregnant person. 

Our blog is backed by extensive research from multiple medical sources, although not all are cited here. The OpenUp editorial team and lifestyle experts have conducted thorough research; please feel free to contact us for more information on the additional references.

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