The third trimester has arrived. Your belly continues to grow, your baby is undergoing enormous development, and birth is drawing closer. For many women, this is a special period in which enthusiasm and curiosity go hand in hand with excitement and uncertainty. Your body is working at full capacity to give your baby the best start.
A lot changes during these final months of pregnancy. Not only is your baby growing at a rapid pace, but your body is also preparing itself step by step for birth. A healthy lifestyle, sufficient rest, and the right nutrients play an important role in this.
In this comprehensive blog, you will read about what happens during the third trimester, which symptoms are normal, how you can prepare yourself physically and mentally for birth, and which nutrients are extra important during this final phase of pregnancy.
When does the third trimester begin?
The third trimester runs from week 28 up to and including birth, usually around 40 weeks of pregnancy.
This period may well see the biggest growth spurt of the entire pregnancy. Whereas the first two trimesters were mainly focused on the formation of organs and the development of body structures, the emphasis now is on:
- rapid growth
- lung maturation
- brain development
- building up fat reserves
- preparing for life outside the womb
Your baby is getting stronger, moving more powerfully, and taking up more and more space.
Your baby's development during the third trimester
Your baby is growing at a rapid pace
From around 28 weeks, a baby weighs on average slightly more than one kilogram. At birth, this is usually between 3 and 4 kilograms.
During the final weeks, your baby grows hundreds of grams every week. It is not only weight that increases; the brain is also developing at an impressive pace.
The brain is undergoing an enormous growth spurt
During the third trimester, millions of new connections are formed between brain cells. This helps develop functions such as:
- memory
- learning
- motor skills
- sensory processing
- sleep-wake rhythm
DHA, an omega-3 fatty acid, is also absorbed in large quantities by the brain and retina during this period.
The lungs are maturing
Although the lungs were formed earlier, they only truly mature during the final weeks of pregnancy.
More and more surfactant is being produced. This substance prevents the air sacs in the lungs from collapsing after birth and is essential for proper breathing.
This is why every extra week in the womb can make a big difference for babies who are born too early.
Your baby is storing nutrients
During the third trimester, your baby is building up important reserves of, among others:
- iron
- vitamin B12
- fat
- calcium
- phosphorus
These reserves are important for the first months after birth.
What is changing in your body?
Your uterus is reaching its maximum size
At the end of pregnancy, your uterus is about five times larger than it was before pregnancy.
This creates more pressure on:
- your lungs
- your stomach
- your bladder
- your pelvis
- your ribs
This explains why many pregnant women get out of breath more easily or need to urinate more often.
Your blood volume is at its maximum
During pregnancy, your blood volume increases by approximately 40 to 50%.
This extra blood is needed to:
- keep the placenta well-supplied with blood;
- transport oxygen and nutrients to your baby;
- better manage blood loss during birth.
This significant increase also creates a greater need for iron.
Your hormones are preparing you for birth
In the final weeks, the hormonal balance changes again.
Under the influence of, among others:
- oxytocin
- prostaglandins
- relaxin
your body is preparing for:
- softening of the cervix;
- loosening of the pelvic ligaments;
- the onset of contractions.
So your body has been working hard behind the scenes for weeks before birth.
Common complaints during the third trimester
Fatigue
Many women notice that their energy levels decrease again.
This is due, among other things, to:
- the rapid growth of your baby;
- poor sleep;
- increased energy expenditure;
- the extra weight you are carrying.
Therefore, listen carefully to your body and schedule plenty of rest periods.
Pelvic and back complaints
Your posture changes as your belly grows.
In addition, the hormone relaxin causes ligaments to loosen, so your pelvis can prepare for birth.
This is a normal process, but can also lead to:
- lower back pain;
- pelvic instability;
- pain around the pubic bone;
- pain radiating down the legs.
Regular exercise, good guidance from a pelvic floor physiotherapist, and avoiding prolonged standing can help.
Heartburn
Because the uterus pushes up on the stomach and progesterone relaxes the muscle between the stomach and esophagus, many pregnant women suffer from reflux.
Small meals spread throughout the day often work better than three large meals.
Edema
Water retention in the feet, ankles, and hands is common.
This is usually harmless and is caused by:
- hormonal changes;
- the increased amount of body fluid;
- pressure from the uterus on the blood vessels.
Sudden, severe water retention, especially in combination with a headache, seeing spots, or upper abdominal pain, should always be discussed with your midwife or doctor.
How do you prepare for birth?
Take a pregnancy course
Good preparation often leads to greater confidence.
During a pregnancy course, you will learn, among other things:
- how contractions work;
- breathing techniques;
- relaxation;
- positions during birth;
- the role of your partner.
Research shows that good information can reduce anxiety about birth.
Think about your birth plan
A birth plan is not a script, but a way to think about your wishes.
For example, think about:
- who will be present;
- pain relief;
- the atmosphere;
- music;
- initial skin-to-skin contact;
- breastfeeding.
Always discuss this with your midwife.
Relaxation
During birth, relaxation helps your body work better with the contractions.
Consider:
- breathing exercises;
- mindfulness;
- pregnancy yoga;
- meditation.
Stress increases adrenaline, while relaxation supports the release of oxytocin, the hormone that plays an important role in contractions.
Nutrition during the third trimester
Many women think that nutrition becomes less important at the end of pregnancy. The opposite is true.
Your baby has an increased need for various nutrients right now.
Iron
During the third trimester, the need for iron increases significantly.
Iron supports, among other things:
- the production of red blood cells;
- oxygen transport;
- the growth of the placenta;
- the build-up of your baby's iron stores.
An iron deficiency can contribute to anemia, fatigue, and reduced fitness.
Combine iron-rich foods, such as legumes, whole grains, meat, or leafy green vegetables, preferably with vitamin C to improve absorption.
Omega 3 (DHA + EPA)
DHA plays an important role in:
- brain development;
- the development of the nervous system;
- the development of the eyes.
Because a lot of DHA is transferred to your baby during the final weeks of pregnancy, several international guidelines recommend that pregnant women get enough DHA.
Choline
Choline still receives relatively little attention, although it is important for:
- brain development;
- nerve development;
- cell division.
The need for choline increases during pregnancy.
Magnesium
Magnesium supports:
- normal muscle function;
- the nervous system;
- energy metabolism.
Although magnesium is not a proven treatment for normal pregnancy cramps or for preventing premature birth in healthy pregnant women, adequate intake through food and supplements is important to meet the daily requirement.
Calcium and vitamin D
These nutrients work together to support:
- strong bones;
- tooth development;
- muscle function.
When intake through food is insufficient, a supplement can be a valuable addition.
Why a trimester-specific supplement can be valuable right now
Nutritional needs change during pregnancy. That is why more and more women are choosing a supplement tailored to the phase they are in.
During the third trimester, the focus shifts to nutrients that contribute, among other things, to:
- oxygen transport;
- the development of the brain and eyes;
- your baby's growth;
- your own energy balance.
At MomPwdr, the supplements are specifically formulated based on the changing needs during each trimester, with carefully selected nutrients in highly absorbable forms and dosages that align with the latest scientific insights.
Frequently asked questions about the third trimester
When does the third trimester begin?
The third trimester begins at 28 weeks of pregnancy and continues until birth.
Can my baby be born now?
From around 37 weeks, a pregnancy is considered full-term. If a baby is born earlier, it is considered premature. The further along the pregnancy is, the better the prospects generally are.
Is it normal that my baby moves less?
The movements may feel different because there is less room, but your baby should remain active every day. If you clearly notice less movement than you are used to, always contact your midwife or the hospital the same day.
Which nutrients are extra important now?
Among others, iron, DHA (omega 3), choline, calcium, vitamin D, and sufficient protein play an important role during the third trimester.
