What Is A Trimester?

Your pregnancy is divided into three trimesters. How will each one affect your body and emotions? Pregnancy brings a lot of changes for women. This post will help give you an idea of what you can expect during each stage.

The 9 months of pregnancy are divided into three trimesters but not every doctor will separate them in exactly the same way. For this post I’m going to make each one about 13 weeks long – just like I’ve done with my pregnancy.


First Trimester: 0 to 14 weeks

The first trimester begins on the first day of your last period. Your body is busy preparing for ovulation – creating an ideal atmosphere for conception to occur. Many women don’t know they’ve successfully conceived until weeks 5 and 6 roll around (the missed period is usually a dead giveaway to take a pregnancy test). The first trimester ends after week 14.

Physical and emotional symptoms can be pretty intense during the first trimester. Your body is being flooded with heightened levels of progesterone, estrogen and HCG (human growth hormone). Most of your symptoms will come from the progesterone. This is a new experience for your body. It has to adjust to all of the chemicals being released  – a process that can take many weeks or months.

Until your body becomes accustomed to these changes you can expect to experience any or all of these physical symptoms – or none of them: morning sickness, fatigue, food aversions, cravings, sore breasts, dizziness (or fainting), having to pee more frequently, hormonal acne (or clearer skin), heartburn, bloating and constipation (or incontinence). Some of these symptoms contradict themselves and there’s no telling which symptoms you’re going to have. Every woman (and every pregnancy) is completely different and comes with it’s own unique challenges.

Emotionally the first trimester can be a little intense. You are growing a baby after all – so be patient and kind with yourself. Many women find themselves caught off-guard by the intensity of their pregnancy symptoms and how those symptoms effect their lives. You might not have expected to be quite this tired. Morning traffic has you sobbing on your daily commute. Your body feels different – nothing you put on seems to fit properly – you can’t think clearly to preform at the level you’re accustomed to – etc, etc.

Pregnancy often brings out the insecurities in every woman (even those of us who wanted to get pregnant more than anything). The way you react to these feelings is not an indicator of what kind of mother you will be when your child is born. Having a child will change your life. It will deepen what kind of woman you will become in the process. Give yourself permission to use these 9 months to process this huge life event without judgement. (I know – easier said than done. When you feel overwhelmed eat a muffin and close your eyes for 10 minutes – or take a nap. You’ll feel so much better.)

Second Trimester: 15 to 27 weeks

The second trimester is universally considered the best stage of pregnancy. It begins 15 weeks into your pregnancy. By the time the second trimester starts your body should be accustomed to most of the hormone fluctuations – which means most of your first trimester symptoms should subside. You will probably get a boost in energy. This is a great time to begin exercising and setting up your home for the baby. This is also a good time to create a registry, start taking birth classes, find a pediatrician and begin thinking about what kind of birth you want to experience. The second trimester ends after week 27.

Physically you should have less nausea and exhaustion during the second trimester – a sign that your body has adjusted to the progesterone levels from the baby. However, your body will change rapidly during these next few months so expect new symptoms to replace your old ones from the previous trimester. Your baby is experiencing rapid growth and so is your belly! This growth, combined with increased blood volume and a new hormone relaxin, may cause the following physical symptoms: back pain, sensitive (sometimes bloody) gums, swollen breasts, nosebleeds, congestion, peeing even more frequently, headaches, heartburn, constipation (or incontinence), hemorrhoids, stretch marks, foot growth, varicose veins, numbness or tingling in hands/feet and weight gain.

Most of these physical changes are temporary and will lessen or disappear after your pregnancy ends. To help minimize second trimester symptoms focus on (1) eating a varied and balanced diet, (2) drink 12 to 14 (8 oz) glasses of water every day and (3) limit your intake of carbs and sweets so your belly expands at a more even rate.

Emotionally, the second trimester is the easiest of your entire pregnancy. You may still experience some mood swings but overall you should notice an increase in energy and stamina compared to your first trimester experience. Use this time to get your house ready for baby. Create a birth plan. Fill your freezer with food for after baby arrives (no one likes to cook after labor). Plan your nursery! This is the most energy you will have for your entire pregnancy.

Third Trimester: 28 to 40 weeks

Welcome to the home stretch! The third trimester begins 28 weeks into your pregnancy. Hopefully you planned well during the second trimester when you had the energy to think – thinking and moving will become very difficult from here on. Most of your baby’s organs and systems are developed by the end of the second trimester. During the third trimester growth will be focused primarily on their brain and fat deposits. This may leave you sleepy, tired and confused. Remember to take it easy – take naps – lay down – drink water. Rest. Every day you’re working just as hard as a professional body builder or mountain climber just by sitting down and growing your baby. This will all end with labor.

Physically your body is going through a lot of changes during this trimester. You will double in size over the next three months. Your baby will grow from 2 lbs up to 6 or 8 lbs in a very short amount of time. This will put strain on your hips, back, spine and pelvis. Expect to experience increased back pain, hemorrhoids, swelling over entire body (raise your feet over your heart on pillows), headache, braxton hicks contractions (false labor), spider veins, stretch marks, breast growth, the constant need to pee, heartburn, constipation, breathlessness, nearsightedness, nausea, dizzyness, round ligament pain and intense fatigue. Does that seem like a lot of symptoms? It’s just your body’s way of making the final preparations for birth. You may not experience all of these symptoms…but you will likely experience most of them.

This is why it is so important to get rest and not push yourself too hard. Your body is going to struggle a bit under all the excess weight of pregnancy. Keep off your feet as much as you possibly can.

Emotionally the third trimester can be challenging for some women. After all – in 3 months you’re going to be a mother. That is a big responsibility and it can be both exciting and scary. You can do it! You just need to rest and be kind to yourself. “Pregnancy brain” can also make accomplishing daily tasks more difficult for you this trimester. Your brain is actually slightly swollen during the third trimester. Simplify your daily routine and don’t expect more from yourself than you are able to give. Ask friends and family members for help cleaning the house and running errands for you. Staying active can help maintain your strength for labor but be careful not to overexert yourself. Just rest and allow your body to prepare for the amazing event of labor!


These are the three stages of pregnancy in a nutshell. What trimester are you in? What is your experience with it so far? Let me know in the comments section below!

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