The First Trimester
You’re pregnant, now what?? This is a guide to everything you need to know in the first trimester of pregnancy week by week. What to do, what not to do, and tips to make it to that 12 week mark.
My posts contain affiliate links, which mean that I may earn a small commission from your purchase, with no extra cost to you!
If you prefer to listen instead of read, check out my podcast on this topic here.
The first trimester actually begins on the first day of your last period (also known as LMP – last menstrual period). This means that by the time you actually find out you are pregnant, the first trimester is a third or even halfway over!
How is my baby and my body developing during this time period?
Even though you cannot see any changes yet, a LOT is happening. During the first 12 weeks, there is a lot going on! Check out some of the major milestones for each week:
Pin it on Pinterest!

Weeks 1-2
No Baby yet! You are getting ready to ovulate!
Week 3
You have an embryo! Yay! It’s not quite a fetus yet, as it’s still just a bunch of cells multiplying to create that precious little baby.
Week 4
Your baby is on it’s way to your uterus where it will spend the next 37 weeks (give or take). Some women still won’t know they are pregnant for another couple of weeks. Keep an eye out for PMS-like symptoms such as feeling bloated or crampy and you might have some mood swings! Don’t worry if you don’t experience any of this, some women don’t have any symptoms at all! Also, some women will experience implantation bleeding – but don’t worry about this either, it’s totally normal. Your little embryo will split into two parts – one becomes the placenta and the other will become your son or daughter!
Week 5
By now you have missed your period and should be far enough along to confirm the pregnancy using a standard test! You don’t need to spend a fortune on pregnancy tests, I used the dollar tree ones and they worked perfectly. If it’s hard to read the line, THEN go out and buy one of those fancy digital ones. If it comes back negative, wait a few days to a week and then try again, the first time I took a test it came back negative. By now your placenta is starting to form. This is Baby’s lifeline for his/her stay inside your belly. It provides your baby with all of the oxygen and nutrients they need and it helps remove waste from your baby’s blood. This is what the umbilical cord attaches to.
It is common for SOME women to experience early pregnancy symptoms, but some women don’t experience any at all. Don’t worry if you are feeling fine, and just enjoy this time! Some common symptoms are exhaustion, sore boobs, or even a little bit of nausea. Although you may not see a lot going on from the outside, your body is working HARD to grow this little baby.
Now is a great time to start documenting your pregnancy! It goes by so quickly and you will be grateful to have notes to look back on. I just started a word document and would go on once a week to talk about the milestones, appointments, and how I was feeling.
Week 6
This week your baby is starting to develop some major organs like kidneys, liver, lungs, and a heart! Their little heart is already beating at 110 bpm and will continue to get faster. You may be visiting the bathroom often (by 6 weeks I was practically living on the toilet!). This is a combination of a few things; the pregnancy hormone hCG increases the blood flow to your pelvic area, your kidneys are working hard to get rid of any waste, and your little one is starting to push on your bladder. Luckily, the uterus lifts up slightly during the second trimester but you will be back to the toilet during the third. Prepare for your first prenatal visit by deciding which route you want to take for your prenatal care. Check out my post on OBGYN’s or Midwives if you aren’t sure yet!
If you want to learn more about Pregnancy Hormones, check out this awesome guest post by Katie and Courtney, a Midwife and OBGYN team over at the P.U.S.H Revolution: Pregnancy Hormones
Week 7
Your baby’s umbilical cord is developed! This will be their lifeline for the next 33 weeks! Little buds will appear where their limbs will start to grow. Your boobs will start to change as they prepare for your baby’s arrival. They will start to get bigger, your nipples will get pointier, and your areola will get darker which helps your baby see them after birth for a better latch. Some common symptoms at this point are breast tenderness, fatigue, constant urination, cravings or aversions, heartburn, or even extra saliva.
Week 8
Baby’s heartbeat is now up to 150 to 170 bpm which is about twice as fast as mine and yours! Amniotic fluid is increasing and your uterus is getting bigger. Some first time moms may feel like they are showing by now, but it is most likely just bloating. In either case, if your pants might be starting to get a little tight – check out this bellaband so you can start leaving your pants unbuttoned!
Morning sickness can start to come into full force and is experienced by 3 out of 4 pregnant women. Whoever created the term is a big fat liar, because morning sickness does not just exist during the mornings. If you aren’t feeling so great, try switching up the time that you take your prenatal vitamins and try keeping a few crackers by your bed. It can help to eat multiple small meals throughout the day so you are never starving, but never super full either.
I had my first appointment at 8 weeks. Don’t be shocked when the ultrasound machine doesn’t look like the one in movies. Early on, a lot of doctors will use a transvaginal ultrasound which looks like a wand and goes inside of you instead of the typical belly one. Most people suggest to wait until after the first trimester to share the exciting news, but we just couldn’t wait! I am a fairly open person, so I would want my friends and family there for us IF anything had happened. Do whatever you think is the best decision for YOUR family, and don’t let others pressure you into a decision you aren’t comfortable with. This is your big news and you get to share it whenever you are comfortable.
Week 9
Although you won’t be able to feel any movement for a few more weeks, Baby is already starting to make tiny arm and leg twitches as their muscles start to develop. Curious about the gender? You can take the Sneak Peek test (on Amazon) to find out if you are having a little boy or girl. Although it is accurate starting at 8 weeks, I waited until 9 weeks just in case. Read more about my review and experience here. If you weren’t feeling tired before, you might be now. If you are dragging your feet, just know that you should have a break soon! Once your placenta is done developing, you should have a little bit more energy. If you have been feeling some heartburn try these tips:
- Eat small frequent meals
- Avoid spicy or greasy food
- Try antacids like Tums (the extra calcium helps and you need it during pregnancy anyways)
- You can also try drinking milk or almond milk for the extra calcium.
If none of these tips work, talk to your doctor. They will be able to prescribe some more efficient medications that are totally safe for you and baby!
Week 10
Your baby is no longer considered an embryo and is now considered a fetus. Remember when I said you need some extra calcium? Well this week, all that extra calcium is helping out with the development of Baby’s bones! His/her teeth are also starting to form under the gums, but they won’t make an appearance until they are about 6 months old.
At this point, you might be starting to show! Your baby is now big enough that you might be able to see a slight bump in your lower belly. For me it just looked like I ate too many tacos, but every woman is different. If you aren’t showing yet, don’t worry – you will be soon enough! You might have some added symptoms this week as well. The first could be round ligament pain – this is caused by the stretching of ligaments supporting your belly. As your belly starts to get bigger, you might feel either a dull or even sharp/shooting pains in the bottom of your belly (it’s totally normal).
The second symptom is caused by the increase in blood flow. You might be able to see your veins now, but this is also completely normal! When you are pregnant, your body has about 150% of it’s normal blood volume, which might make your veins stand out a little more than normal.
Week 11
Your Baby’s webbing between his/hers fingers and toes are disappearing. They are looking less like a tadpole and more like a baby now! Baby is now able to move around a little more and as they start to get bigger, you will start to feel these movements! Hopefully you don’t have much longer with the morning sickness and the second trimester is right around the corner. This is considered to be the best trimester by most women, so just hang in there Mama!
Week 12
The end of the first trimester!! Your baby has doubled in size of the past three weeks and is going to continue to grow like crazy! Although the end of the first trimester doesn’t necessarily mark the end of all of these pregnancy symptoms, most women start to feel much better about now. If you are still feeling like poo, don’t worry! The symptoms tend to go away as fast as they appeared and one day you will (hopefully) wake up feeling so much better.
If you didn’t get a chance to hear your baby’s heartbeat at the last appointment, you should be able to hear it at this month’s appointment! Another great thing about the end of the first trimester: you have to pee less! As your uterus moves upwards, it releases the pressure on your bladder. Enjoy this time, because by the third trimester the baby will be so large that the pressure is right back on your bladder (and it is accompanied by movements and kicks).
You are now a third of the way through your pregnancy! Have you started logging it yet? The days will go by slowly, but the months go by quickly and soon enough you will be holding that little bundle of joy in your arms! If you haven’t announced your pregnancy yet, the chances of miscarrage have greatly decreased by now, and this is a very common time for couples to announce the newest member of the family.
As your baby starts to get larger, your ribcage gets bigger as well. Your underwire bras might start getting a little uncomfortable. I purchased nursing bras right around this time and they are so comfortable. If you would like to check out my full review on them, click here.
Now is also a great time to start looking into baby registries. I have a full list here of the top registries, the free items they will send you, completion discounts, and other great perks. I was glad to start my registry early so I could add all of the suggestions as they came. Once you start showing, people love to suggest items that worked for them, which items to avoid, and the must-haves that they couldn’t live without. Your baby registry is a great place to create a list that you can go back through later to do research and make decisions.
Click the following links for more information regarding the Second and Third Trimesters!
Subscribe!
If you enjoy these posts, subscribe to our newsletter on the side bar or the contact page! It’s completely free and I promise not to spam you, just updates on new content once a week.
