Everything You Want To Know About The First Trimester

baby announcement picture, all the things to know bout frist trimester as a first-time mom

Ah, the first trimester. The months of joy and excitement about coming changes, but also the months of pure agony and nausea. Curious to know what’s going to happen? Well below are all the things to know about the first trimester for first-time moms! 

Starting your pregnancy journey is exciting, nerve-wracking, but also kind of scary. There are so many things happening, things you should do, not do, and not even mentioning all of these new symptoms you are experiencing! 

It can be a lot to take in, but that’s okay. 

The secret is to take it slow and inform yourself. The more informed you are, the better you can make the right choices for yourself and for the baby. 

And to take that first step, we are here to help and inform you on all the things to know about the first trimester for first-time moms! 

7 things to know about First Trimester for First-Time Moms 

-when does the first trimester start and end? 

-first-trimester symptoms 

-first-trimester body changes 

-baby development and milestones 

-any tests and upcoming appointments 

-things you should do 

-things you should avoid doing 

When Does First-Trimester Start and End? 

The first trimester starts on week 1 and goes until the end of week 13. 

The MonthsThe Weeks
11-4 Weeks
25-8 Weeks
39-13 Weeks

Sounds complicating? That’s because it is, as your pregnancy is actually measured from the first day of your last period and not from your conception date.  

Therefore, when you find out you are pregnant, you are usually a few weeks along already! 

Still confused? Here is a handy due date calculator to help you figure out when your due date is and explain the counting of pregnancy weeks more in-depth. 

What Are Some Symptoms? 

woman feeling symptoms of the first trimester

During your first trimester, you may experience some of these symptoms. These are just an estimate as not every woman will experience these to the same degree and at the same time. But being aware of these symptoms also is a good thing to know about first trimester for a first-time mom.

Signs and Symptoms Timeline (from missed period) 
Mild cramping and spotting Week 1 to 4 
Missed period Week 4 
Fatigue Week 4 or 5 
Nausea  Week 4 to 6 
Tingling or aching breasts Week 4 to 6 
Frequent urination Week 4 to 6 
Bloating  Week 4 to 6 
Motion sickness Week 5 to 6 
Mood swings Week 6 
Temperature changes Week 6 
High blood pressure Week 8 
Extreme fatigue and heartburn Week 9 

If you are interested in more of the signs and symptoms of early pregnancy, check out The 12 First Signs and Symptoms of Pregnancy that goes into much more detail! 

First Trimester Body Changes in First Time Moms 

A lot of things are happening to your body in the first trimester, and keeping track of these things may be hard, as your baby’s development and your bodily changes are differing from day to day. 

first trimester body changes in first time moms, woman sitting on couch holding her belly

What about a Baby Bump? 

You will probably not notice a significant baby bump during the first trimester. However, bloating and changing hormones may mean your stomach is rounder and your jeans are getting tighter. 

This bloating is what most women conceive as an early baby bump, but it’s actually just air in there at the moment! 

Here is a quick run-down of what is happening in your body week by week: 

  • Weeks 1-2 : You actually haven’t conceived yet, so you technically aren’t pregnant yet. 
  • Week 3 : You have conceived! And little baby is starting to grow, congratulations! 
  • Weeks 4-6 : You may start feeling some of the earliest signs of pregnancy such as sore breasts, nausea, tiredness, and a frequency to urinate. 
  • Weeks 7-12 : By now the pregnancy symptoms are sure to have kicked in and your fatigue and nausea are most likely in full blow. Due to all the bloating, your stomach may appear to be showing a bit of a bump, but it’s not baby quite yet! 

Related Posts:

Everything You Want To Know About The Second Trimester

Everything To Know About The Third Trimester

Baby Development and Milestones 

  • Weeks 1 and 2: Considering you start counting your pregnancy from your last period, you are technically not pregnant yet! 
  • Week 3: It is during this week that you are officially pregnant as fertilization has occurred. Congratulations! 
  • Week 4: Implantation has happened. The group of cells that are going to grow into a beautiful baby have implanted themselves into the lining of your uterus. 
  • Week 5: By now, the embryo will be made from 3 layers, which will make up the skin, circulatory system, and the other body systems. 
  • Week 6: Some important features of your fetus are developing at this stage, and your fetus is starting to look more and more like a human being, with the head becoming more and more pronounced. 
  • Week 7: Your baby’s brain and face are developing rapidly at this point. Stubs that make out the legs and arms are growing more and more. 
  • Week 8: Your baby’s face is forming more and more as the eyes and nose are now starting to develop. 
  • Week 9: Toes, arms, and elbows are starting to appear. Your baby’s head is big but is not quite the shape of a human head yet. 
  • Week 10: By now, the umbilical cord is clearly visible, and the elbows are forming more and more, and baby may even be able to bend them! Toes and fingers have lost their webbing and are growing longer and are looking more like human feet and hands. 
  • Week 11: It’s officially a fetus! Your baby’s head is still half the length of your baby, but the body and red blood cells are beginning to develop. The genitals are also beginning to form by now, but you won’t be able to see them until an ultrasound later. 
  • Week 12: Your baby’s face is developing at super speed, and even their fingernails have formed already! 

Any Upcoming Tests and Appointments? 

If you suspect you are pregnant, contact your health care provider to confirm your pregnancy. They will most likely get you to do a blood test that will confirm elevated hCG levels in your blood (a pregnancy hormone). 

Between 8 and 13 weeks you will be scheduled for a dating ultrasound. This will confirm there is a heartbeat, and you may even get to hear it! They will also do some measurements that will help give you a more accurate due date. 

This one is optional, but between 11 and 14 weeks you will be given the option for genetic screening. Through a blood test and maybe an ultrasound, they will measure the fluid and tissue at the back of your baby’s neck and cheeks for chromosomal abnormalities. 

What Should you do in the First Trimester? 

everything to do in the first-trimester, woman holding ultrasound picture

Make Sure You’re Pregnant 

A faint-line may not be enough evidence to prove you are really pregnant, so make sure you get it confirmed by a doctor or take multiple tests over the span of days or weeks. 

However, getting it confirmed by a health professional is highly recommended. 

Start Taking Your Prenatal Vitamins 

If you aren’t already taking your prenatal vitamins, make sure you start taking them now. They will provide you and your growing baby with essential vitamins that will help prevent certain neural tube defects. 

Even if you are eating healthy, certain nutrients are very hard to absorb and obtain in the right amounts, so a prenatal vitamin will ensure you are both getting everything you need! 

Health Insurance 

Now is the time to look into your health care and what they cover with giving birth and prenatal costs. Calling them and informing yourself of your future expenses should be done sooner than later. 

Choose a Healthcare Provider 

If you already have a healthcare provider such as a doctor or midwife, then you’re set! If not, gather recommendations and choose who will be guiding you through this journey. 

Get Lots of Rest and Take Care of Yourself! 

Your body is going through some immense changes, which you can probably feel by your insanely low energy levels at the moment. 

Make sure to rest lots and give your body time to recover from the daily miracles it’s performing! 

Can’t seem to get comfortable? Getting a pregnancy pillow is probably the answer as they give you support where you need it most for the ultimate sleep experience! Not sure which one to buy? Read Which Pregnancy Pillow is Best For Me? A Quiz to help you find your perfect pregnancy pillow! 

What to Avoid During the First Trimester 

what not to do in the first trimester, all the things to know about the first trimester for first-time moms

There are a few things you should avoid doing during your first trimester, some of which may sound silly but could have negative consequences on you and your baby! However, we will briefly cover them as these are also good things to know about first trimester for first-time moms!

Don’t Eat These Foods! 

There are certain foods pregnant women should refrain from. From undercooked foods, you can get salmonella and food poisoning, which can even end in miscarriages in extreme cases. Or these items may contain bad bacteria called listeria that can cross the placenta and infect your baby. 

So, staying clear of these just to be safe is always a good idea! 

Here are the foods you should do your best to avoid: 

  • -raw/undercooked meat and shellfish 
  • -deli meats 
  • -high mercury fish 
  • -smoked seafoods and fish 
  • -raw and undercooked eggs 
  • -soft cheese 
  • -unpasteurized dairy products 

Wanting to know why these foods are bad and the impact they can have? Check out this blog post for more information! 

Tone Down on the Caffeine 

Caffeine actually crosses the placenta, meaning if you consume caffeine your baby is consuming it, and they don’t tolerate it as well as we do! 

However, research says 150 to 300 milligrams of caffeine per day is still okay and that it won’t negatively impact your developing baby. So, limit yourself to that one cup of coffee, or even better, go decaf altogether! 

Be Careful with Over-the-Counter Medicine 

Some medicine such as Advil should be avoided during pregnancy. If you need pain meds or any other type of medication, make sure to contact your doctor or health care provider first! 

No Hot Tubs or Hot Baths 

Hot tubs and steaming hot baths raise your body temperature over its normal limit, which usually isn’t a big deal. Except you have twice the amount of blood coursing through your body, and your blood pressure can skyrocket quickly. 

So, stay out of the hot tubs and saunas, and take some warm, not hot baths instead! 

Don’t Change the Kitty Litter 

Cat feces may contain a harmful parasite which can have drastic effects on an unborn baby. Therefore, give the kitty litter task to someone else, or if you must, wear gloves masks and sanitize everything and yourself thoroughly to avoid contamination! 

Don’t Consume Alcoholic Drinks 

You probably already know this, but I wanted to mention it anyway. Consuming alcohol during pregnancy can have life-changing effects on your baby. 

Alcohol quickly passes through the placenta to the baby, and this can severely harm your baby’s developing brain and organs. 

So, lay it off the beer, wine, and alcoholic drinks, you’ll get to enjoy them soon enough! 

Your first trimester comes with a lot of changes, some exciting, some not so exciting. Being informed about what’s happening and what may happen, is the best way to have a healthy and safe pregnancy. 

I hope now after reading all the things to know about first trimester for first-time moms you are ready to dive into this wonderful adventure of pregnancy. 

Is there anything we didn’t answer? If you have questions, let us know in the comments below and we will be sure to answer them! 

If you would like more updates and tips on your pregnancy journey, make sure to follow us on our social media, and subscribe to our weekly newsletter! 

Until next time, 


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