Physiology of pregnancy in the Third Trimester at a glance

Third Trimester

During the third trimester, that is, from 28 weeks onwards, interesting physical and psychological changes begin again. From the 26th week (maybe even earlier) Mum’s body has begun to produce milk. 

Do not find it strange if your breasts start dripping! And do not stress, you will continue to have milk for your baby, it does not run out. For more information on the creation of breast milk view the relevant article.

From this week onwards we expect there to be a “rhythm” or a pattern in fetal movements. 

What size is the baby?

In the third trimester of pregnancy it is very important to eat properly as it is at this stage that the baby begins to grow and gain weight. It goes from 1900 grams up to 4 (or even 5) kilos!

In this trimester your baby grows, having mostly developed all the important organs in the previous months. 

Fun fact: From 34 weeks your baby’s lungs are developed and they are getting ready for the outside world! Time to pack your hospital bag!

How long can a pregnancy last?

A normal pregnancy lasts up to 42 weeks. The World Health Organization defines a “full-term” pregnancy as any pregnancy from 37 to 42 weeks. The “estimated due date” is the day when the 40th week of pregnancy begins. 

Only 5% of babies are born on this date. This phase of pregnancy requires patience. 

It is important to also know that the “trimesters” of pregnancy are measured in lunar months, that is, thirty-day cycles. For this reason, although a full-term pregnancy is considered any pregnancy after 37 weeks, your pregnancy can last longer. After all, you may eventually be pregnant for 10 months! And not 9 that we used to say for so many years!

Preparing the body for childbirth

The last trimester is when some symptoms of discomfort begin again, such as frequent urination, muscle aches, cramps and fatigue. Your body is getting ready for birth. From 30 weeks onwards you may feel some pains and pressure such as mild period pains or “tightening” of the abdomen from time to time, especially with exertion.

These pains are called Braxton Hicks and are “preparation” pains. These are usually not painful and do not require painkillers or any action from you. If you feel that the pains are intense and frequent and you are under 37 weeks, go to the nearest hospital or clinic of your choice.

For more information about braxton hicks contractions and the signs of the onset of labour please go to the relevant article.

Join out childbirth preparation classes for more details on the third trimester and preparation for birth here at Hera Family Care!