What to Expect in Pregnancy During the First, Second, and Third Trimesters
You’re pregnant! Now, what happens? Let’s take a look at the 3 pregnancy trimesters and what changes you will notice happening!
A full-term pregnancy can range from 37 – 42 weeks, with your due date being calculated for the 40-week mark. These weeks are divided into 3 periods called trimesters, each ranging anywhere between 12 – 14 weeks (about 3 months). Every pregnancy is unique in its conditions and length, but one thing is for sure: your body is about to go through a lot of hormonal and physiological changes.
Understanding how your baby is growing and the changes that may occur to your body will help empower you throughout your pregnancy. If this is your first pregnancy, this is likely all new. So take it slow, learn as much as you can and make sure you have a strong support system in place.
FIRST TRIMESTER (0-12 WEEKS)
The first trimester is infamous for morning sickness, tiredness, and fear of miscarriage. Many people find out they are pregnant between 4-6 weeks and wait until the end of the first trimester to tell people they are expecting. Commonly people wait to announce their pregnancy until after 12 weeks, but more often now people are announcing early to have the support and love they need in case something was to happen.
In early pregnancy, you are building a whole new organ, the placenta, nearly doubling your body volume and creating an entirely new human from two cells. No wonder you are tired!
What about your baby? Even within the first 4 weeks many of the essential foundations of baby’s systems are forming! During the first 12 weeks, while the baby is growing, they are the most vulnerable.
0-4 weeks – the embryo looks like a tadpole
- The neural tube, which becomes the brain, is forming
- All major systems, including the digestive system, the heart, and circulatory system start to form
- Eyes and ears are beginning to develop
- Small limb buds appear, which become the hands and feet
5-8 weeks – the embryos look are changing to more resemble a baby
- They are only 1 – 1.5 inches long
- All of the major organs and systems have been formed
- Bones, nose, and jaw are developing
- Fingers and toes are webbed but easily visible
- Arms and legs can be easily seen
- Eyes, nose, ears, and mouth (with teeth buds) are more visible
9-12 weeks – the embryo is now the size of a passion fruit
- Fingernails and toes appear
- External genital organs are developed
- Voicebox begins to form
- Eyelids, arms, and legs are fully formed
Nearing the end of the first trimester is a good time to think about pregnancy, childbirth, breastfeeding, and parenting classes, and find one that you like.
SECOND TRIMESTER (13-28 WEEKS)
There are so many changes happening during the second trimester! Your body is changing, your baby’s body is growing rapidly and you might just be feeling a little more energy.
Your anatomy scan will happen around 20 weeks too! This ultrasound isn’t just for finding out your baby’s gender, it’s a full look into the development and growth of baby.
All of these changes (and more) are covered in the Empowered Birth course to help you navigate your pregnancy with ease!
In the middle of your pregnancy, your centre of gravity is shifting forward, you are creating milk ducts in your breasts and your hormones are loosening your joints. The hard formational work from the first trimester is behind you now so hopefully, you are a little less exhausted and nauseated.
You will likely start to see your bump forming and growing and might even start to feel some early kicks by 16 weeks! While most of the early symptoms of pregnancy are gone, some people complain about leg cramps and heartburn – talk to your care provider for some solutions to these common issues.
Your baby’s head is about half the size of his crown-to-rump length – that is a big noggin. That big brain of their is developing rapidly and is taking in all of the information happening around them. Babies will play with and squeeze the umbilical cord, stretch their arms and legs, practice breathing and sucking, and will watch as the light changes coming in through the stomach! You may think it’d be boring in there, but wait until the late-night dance parties start!
13-16 Weeks – from the size of a lemon to 4-5 inches long
- That’s right. Baby will go from the size of a lemon to being 4-5 inches in length (and about 3-4 ounces)
- Baby begins to practice swallowing and produce urine (don’t worry, its sterile)
- The sex of the baby becomes apparent
- The hair pattern begins to form
- Bones start to harden
- Movements become more coordinated
17-20 Weeks – heavy baby alert!
- During this time, your baby will grow to 10 ounces!
- Toenails are developing
- The ears have fully developed
- Baby can start to hear sounds
- The digestive system has started to work
- Vernix, a waxy or cottage cheese-like white substance, begins to form and coat baby’s skin for protection
21-24 Weeks – baby cam time! You can start to tell what baby will look like
- Baby can suck their own thumb and hiccup
- Eyebrows and hair will become visible
- Fingerprints and footprints form
- Eyes start moving rapidly
- Skin is pink, or red, and still translucent
25-28 Weeks – A foot long!
- By the end of your second trimester, your baby is measuring more than a foot-long
- Baby will respond to voice so you can talk to your baby
- Lungs are developing and producing surfactant, a coating on the inside lining of the alveoli. This coating makes it easier for the alveoli to expand during breathing. It also keeps the alveoli from collapsing and sticking together when the air leaves the lungs.
- Baby is gaining fat and spends more of their time sleeping
- The nervous system is maturing
THIRD TRIMESTER (29-40+ Weeks)
Things are getting real! This is your time to slow down, enjoy and soak up all the rest you can before that sweet little baby arrives! Did you know just sitting there, your heart rate is equivalent to when you exercise? Your body is working really hard so you might get more tired and a little achy.
Nourish your body with good foods during the third trimester to build up your energy and give you a boost heading into labour. You’ll also start seeing your healthcare provider regularly. It’s a good idea to be taking a childbirth class in preparation for “labour day”. You need to know a lot about making your labour go as smoothly as possible. However, my Empowered Birth Course has got you covered!
This is the home stretch! Baby is still growing in weight and size and the lungs are still maturing. Baby will start to position themselves head down for labour.
28-31 Weeks – All the doctor visits!
- Baby has eyelashes and can open their eyes
- Hair starts growing on baby’s head
- Kicks and stretches are happening often
- Bone marrow has formed
- The central nervous system is working
32-36 Weeks – We’re almost there!
- All major development has finished
- Pupils react to changes in light inside the womb
- Skin smooths out as daft builds up
- Fingernails finish growing
- Fat stores start building rapidly
37 – 40 Weeks – Welcome baby!
- Stretches and wiggling are more common than kicks and punches
- Baby stores energy for the process of birth
- Fat is building up to keep them warm after birth
- Their space is becoming cramped
Getting excited? You should be, it won’t be long till you meet your baby.
Chances are high (about 70%) of first-time parents going over their due date, but it is safest if baby is born before 42 weeks.
Remember, every pregnancy and birth experience is different. Yes, complications can arise. However, if you are educated, have a strong support system, and a good medical team, you and your little babe will be supported in the best possible ways.
Want to learn more? Check out my Empowered Birth Prenatal Course. Get 6 months access to core video content where we discuss pregnancy and birth in detail and build a birth preference guide, weekly live classes where you and other expecting parents can ask me questions and discuss course content live, expert videos with maternal health specialists, and workbooks, handouts and posters to help you keep track of everything.