Your first-trimester pregnancy guide and checklist

The first trimester of pregnancy is an exciting and sometimes overwhelming time. From discovering you're expecting to navigating the whirlwind of changes happening in your body, there's a lot to take in. But don't worry – we're here to help!

In this guide, we'll break down everything you need to know about the first trimester, from common symptoms to helpful tips for taking care of yourself and your growing baby. Whether it's your first pregnancy or you're adding another little nugget to your family, you deserve to feel confident and prepared for the journey ahead.

What is the first trimester, exactly?

The first trimester is the first of three phases (or trimesters) of pregnancy. It's a critical stage in your pregnancy journey and your baby's development. While your baby bump may not be showing yet, a lot is happening for both you and your baby.

Your baby is growing rapidly – developing a brain and heart, forming facial features, and even growing tiny little feet, hands, fingernails, and toenails. (For more on your baby's development, see our images of fetal development week by week.) In the first trimester, all your baby's major organs and systems form – so you'll want to make sure to take a prenatal vitamin and avoid alcohol, drugs, tobacco, and unsafe medications.

At the same time, your body is changing and flooding with the pregnancy hormones hCG, estrogen, and progesterone. Hormonal changes may bring on unpleasant symptoms that are common during the first trimester, like nausea, vomiting, headaches, and extreme tiredness. Home remedies may help some, but if your symptoms are making life unmanageable, let your provider know.

This trimester you'll choose a doctor or midwife to care for you and your baby, and make several trips to see your provider. Each prenatal visit during the first trimester involves a similar routine: Your provider will check your weight and blood pressure, answer your questions, order tests, take a urine sample, and either listen to your baby's heartbeat or see it on an ultrasound.

"Prenatal care is crucial for a healthy pregnancy," says Shannon Smith, M.D., an ob-gyn at Brigham Faulkner Ob/Gyn AssociatesOpens a new window in Boston and member of the BabyCenter Medical Advisory Board. "Through regular check-ups, providers monitor both Mom and Baby's overall well-being, detect and manage potential complications, and provide education, counseling, and mental health support."

How long is the first trimester?

The first trimester begins at conception and lasts for 13 weeks, or three months. Month one spans from week one to week four of pregnancy; month two begins at week five and lasts until week eight; and the third and final month of the first trimester spans week nine through 13.

A funny thing about the first trimester is that you'll be about a third of the way in before you even know you're pregnant. Pregnancy is counted starting two weeks after the first day of the last menstrual period, explains The American College of Obstetricians and GynecologistsOpens a new window. "So, an extra two weeks is counted at the beginning of your pregnancy when you are not actually pregnant. The 40 weeks of pregnancy includes those extra two weeks." By the time you take a home pregnancy test, you may be four or five weeks pregnant.

If you're not sure, visit our Pregnancy Due Date Calculator to check how many weeks pregnant you are.

Common first-trimester symptoms

In the first trimester, you may feel like an exhausted, nauseated ghost of your usual self. Symptoms can come on quickly and powerfully. "Hormonal changes affect almost every organ system in your body. These changes can trigger symptoms even in the very first weeks of pregnancy," says the U.S. Department of Health and Human Services' Office on Women's Health.Opens a new window

In my opinion, the first trimester is about survival! The nausea truly sucks.

- BabyCenter Community member BTMama2225

But some women have no pregnancy symptoms or mild symptoms during the first trimester. "It's very normal to not have any early symptoms of pregnancy," says Dr. Smith. "About 20% of women never experience nausea or any of the classic symptoms."

If that's you, count yourself lucky. Most expecting moms, though, experience some of the symptoms below.

Morning sickness

Unfortunately, "morning sickness" can last all day – and it strikes about three-quarters of pregnant women during the first trimester. If you have a mild case, some relatively simple measures can help. But if you're still suffering, talk with your provider about other strategies.

"In my opinion, the first trimester is about survival! The nausea truly sucks," says BabyCenter Community member BTMama2225.

Sore breasts

Breast changes, including tender breasts and sore nipples, are usually one of the first signs of pregnancy. Thankfully, your breasts will likely feel less sore by the end of the first trimester. You may also notice the veins in your breasts becoming more noticeable, because they're carrying more blood. Your Montgomery glands (the little bumps on your areola) may be larger and more noticeable, too.

Fatigue

Feeling more exhausted than you ever imagined you could be? In early pregnancy, extreme fatigue is likely due to a dramatic rise in progesterone. You should get some energy back in your second trimester, though you'll likely be tired again near the end of pregnancy.

"I slept a lot in the first trimester," says Community mom Yogurtdonutberry43 in the Baby Names group. "I even fell asleep mid-sentence a few times."

Spotting and bleeding

You may notice spots of blood or light bleeding during the first few days or weeks of pregnancy. This is common, but it's a good idea to tell your provider so they can check that everything's okay.

Headache

Hormone swings and changes to your cardiovascular system may be responsible for first-trimester pregnancy headaches. "Increasing blood volume is thought to trigger more headaches. Your body adapts, and these should resolve on their own," says Dr. Smith. Stress, congestion, allergies, lack of sleep, and dehydration can bring on headaches, too.

Cramping

You may not have expected cramping during pregnancy – just when you thought cramps were over! The usual culprit in early pregnancy is implantation, when the fertilized egg attaches to your uterus. Also, your uterus is expanding and adjusting to being pregnant, which can cause cramping early in pregnancy.

Back pain

Back pain tends to show up more in the second and third trimesters, as your uterus expands, but it's not uncommon to feel it during the first trimester, as hormonal changes loosen your joints and ligaments.

Indigestion, gas, and bloating

Progesterone relaxes muscles throughout your body, including your digestive tract. As the progress of food through your gut slows, you may have indigestion, as well as gas and bloating.

Heartburn

During pregnancy, hormones can relax the valve between the stomach and the esophagus, which means stomach acid can travel into your esophagus and cause heartburn. Some women don't feel heartburn until the second or third trimester, but for others the discomfort starts earlier. Learn safe, natural remedies for heartburn in pregnancy.

Insomnia

Some expecting moms have trouble falling asleep or wake frequently at night. Insomnia can start in early pregnancy and last until delivery, but a few adjustments can help you get better sleep. Find out about natural remedies for pregnancy insomnia.

Increased vaginal discharge

You may notice more vaginal discharge during the first trimester caused by an increase in estrogen. It's usually harmless, but talk to your provider if you have pain, itching, or discharge that smells bad or looks unusual.

Frequent urination

Changes in your hormones, blood volume, and kidney function are usually the cause of constant bathroom trips in the first trimester. Frequent urination can start early, though some women don't notice this symptom until around weeks 10 to 13.

"It drives me crazy!" says BabyCenter Community mom MamaToC2017. "Especially when I'm out and don't want to drag my kids into the bathroom with me so I just feel like I'm going to pee my pants."

Mood swings

All those surging hormones can play a number on your emotions, making you feel irritable, angry, and upset. Get some tips for coping with mood swings, and talk with your provider if you continue to feel sad or depressed. They can refer you to a mental health provider who can help.

Quickened pulse and shortness of breath

Pregnancy-related changes in your body – such as increasing blood volume – naturally change your vital signs. Your pulse may quicken as your body works to pump that extra blood, for example. In the first trimester, a boost in progesterone directly affects your lungs and stimulates the respiratory center in your brain – which can make you feel short of breath or just more aware of your breathing. During pregnancy, you take bigger breaths because you're actually breathing for two!

Congestion and nosebleeds

Greater mucus production and nasal swelling (thanks to hormones) can lead to a stuffy nose during pregnancy. With your increased blood volume and the expanding blood vessels in your nose, you may also have nosebleeds more often. Keep yourself hydrated by drinking enough water, and ask your doctor about pregnancy-safe nasal rinses and sprays.

Note: So many aches, pains, and strange feelings arise during pregnancy that it can be hard to know what's normal and what's not. But if you have any of these concerning pregnancy symptoms, call your doctor or midwife immediately.

Weight gain in the first trimester

For women who start pregnancy at a healthy weight, it's normal to gain between zero and five pounds in the first trimester – though some women may gain more or less, or even lose weight due to morning sickness or other reasons. Here's more info about typical pregnancy weight gain and our Pregnancy Weight Gain Calculator.

Don't worry if you can't eat a well-rounded diet in your first trimester – nausea and food aversions can make this feel impossible. Just do the best you can. Many women feel better eating small, frequent, carbohydrate-heavy pregnancy snacks.

During pregnancy it's especially important to avoid foods that could contain bacteria, parasites, or toxins – including undercooked meat, unpasteurized soft cheeses, anything that contains raw eggs, sushi made with raw fish, raw oysters, and fish that's high in mercury. Find out more about foods and drinks to avoid during pregnancy.

Sex during the first trimester

In your first trimester, you may feel too tired or nauseated for sex. But if you're in the mood and your provider gives you the go-ahead, go for it. Unless you have a specific pregnancy complication, sex is safe during pregnancy. The amniotic sac and the strong muscles of your uterus protect your baby, and a thick mucus plug seals the cervix and helps guard against infection.

Find out more about sex during pregnancy and pregnancy sex positions – you may need to get creative as your belly expands.

First trimester pregnancy checklist

Use this to keep track of all your first-trimester to-do's, from making your first prenatal appointment to taking belly photos.

Take a prenatal vitamin

If you haven't started taking a prenatal vitamin yet, now's the time to start. It's especially important to get enough folic acid during your first trimester, because it greatly reduces your baby's risk of developing neural tube birth defects such as spina bifida.

Investigate health insurance

Make sure you know what your health insurance plan covers as far as your prenatal care and delivery costs, as well as care for your new baby. (For answers, call your health insurance company or talk to your employer's benefits department.) Read more about pregnancy insurance – and find out what to do if you're pregnant and don't have health insurance.

Choose a doctor or midwife

If you already have an ob-gyn, family doctor, or midwife to care for you during pregnancy and deliver your baby, you're set. If not, you've got some research to do. Talk to friends and relatives, ask one of your other providers to recommend someone, check out the preferred providers under your health insurance plan, or search online.

Make a prenatal appointment

Your first prenatal visit is a big one. To prepare, jot down the first day of your last period, any medications you're taking, any medical conditions you have (such as diabetes or high blood pressure), and your personal gynecological history. Talk to relatives on both sides about your families' medical histories. Your provider will want to know whether any chronic conditions or genetic abnormalities run in either of your families.

Get ready to see or hear your baby

If you have an early ultrasound between 6 and 10 weeks, don't be surprised if your baby looks like a gummy bear or lima bean with a tiny, flickering heart.

If you don't have an early ultrasound, you may instead hear your baby's heartbeat around 12 weeks. Many women say it sounds like galloping horses.

Check your medications

Many medicines aren't safe during pregnancy – even some over-the-counter ones. If you take any meds, call your provider to find out if they're pregnancy-safe (but don't stop cold turkey!). Mention everything, even vitamins, supplements, and herbs.

Quit unsafe habits

Smoking during pregnancy, drinking alcohol, and using drugs like opioids and marijuana isn't safe for you or your baby during pregnancy. Talk to your provider and ask for help quitting if you need it. Also, there are some activities to avoid during pregnancy and jobs that are hazardous. Go over your daily routine and ask your doctor or midwife for ways to avoid or eliminate hazards in your home and workplace.

Cut down on caffeine

It's a good idea to cut back on caffeine during pregnancy as much as you can, because it could affect your baby. Experts advise expectant moms to limit caffeine during pregnancy to less than 200 mg per day (that's about one 11-ounce cup of coffee, depending on the brand). Keep in mind that it's not just coffee that contains caffeine – soft drinks, tea, and chocolate have it, too.

Exercise

Being active while you're pregnant can help you stay healthy, sleep better, and boost your mood. You may need to adjust your workout depending on how you're feeling. Talk with your provider about your exercise plan, plus learn the best kinds of exercise for pregnancy and tips for safe pregnancy exercise.

Consider your options for prenatal testing

During your first trimester, your provider will offer you various prenatal tests to check on you and your growing baby. Genetic screening tests can give you information about your baby's risk for Down syndrome as well as other chromosomal problems and birth defects. Two you'll probably hear about in the first trimester are NIPT (noninvasive prenatal testing) and the nuchal translucency test (NT scan).

Think about when and how you'll announce your pregnancy

Some expecting parents spill the tea to friends, family, and co-workers right away. Others wait to announce their pregnancy when they're further along. When you're ready, check out these cute pregnancy announcement ideas and ways to tell your boss you're pregnant.

Start taking belly photos

Have someone take a picture of you every week, or take your own picture using your reflection in a mirror. Tips for a great shot: Consider wearing the same outfit, standing in the same spot, and striking the same pose (profiles work best) for each photo. For inspiration, check out our pregnant bellies photo gallery.

Join your Birth Club

Nobody understands what you're going through as well as other expecting moms in the same stage of pregnancy. Connect with women due the same month as you in your BabyCenter Birth Club.