What To Expect During Your First Trimester

Congratulations – you’re pregnant! From tweaking your diet to choosing a healthcare provider, here’s everything you need to know about the first 13 weeks.


The first trimester of pregnancy can be one of the most exhilarating experiences in the world, but it can also be nerve-wracking as you watch pregnancy hormones take over your body and you anxiously consider everything you need to get done before your little bundle arrives. Knowing what to expect is key and we’ve got your back. Here’s what will happen in weeks one through 13 of your pregnancy.

Your changing body

Some pregnant women feel fantastic and “glow” throughout their pregnancy, while others want to hide under the covers with a tub of ice cream until it’s over. Here are some of the symptoms you may experience in the first trimester.

  • Morning sickness
  • Tender breasts
  • Fatigue
  • Food cravings and aversions
  • Sensitive smell
  • Frequent urination
  • Bloating
  • Discharge
  • Bleeding
  • Constipation
  • Heartburn
  • Headaches
  • Darker areolas
  • Weight gain

With all these changes, it can be hard to tell a normal pregnancy symptom from a worrisome one. Call your doctor right away if you have:

  • Heavy bleeding
  • Severe abdominal pain
  • Severe dizziness
  • Severe puffiness in the hands or face
  • Fever over 101.5°F
  • Visual disturbances
  • Increased thirst without increased urination
  • Very fast or very slow weight gain

Your emotions

You might be euphoric one minute and a sobbing mess the next – welcome to the wonderful world of mood swings. The good news is they’re entirely normal and can be attributed to a combination of fluctuating hormones, fatigue and the worries associated with becoming a parent. Talk to your partner or a close friend or family member about how you’re feeling and cry it out when you need to. But if your negative emotions become too much to handle or you have a history of depression, talk to your healthcare provider without delay.


Your to-do list

Figuring out what needs to be done in the first few months of your pregnancy can be overwhelming, especially when your well-meaning mom friends start to give you advice on everything from car seats to breastfeeding. Many tasks can wait until later in your pregnancy, so put them aside for now. Here’s what you need to get done this trimester.

  1. Quit smoking and drinking:If you haven’t already, now’s the time to give up cigarettes and alcohol for the sake of your baby’s health.
  2. Take a prenatal vitamin: If you weren’t taking a prenatal vitamin while you were trying to conceive, start now. A daily prenatal vitamin significantly reduces the risk of neural tube defects such as spina bifida.
  3. Avoid certain foods: Cut back on caffeine (two cups a day are okay) and avoid foods that could contain harmful bacteria and chemicals, including high-mercury fish such as swordfish and mackerel, unpasteurized dairy and juices, raw or undercooked fish and meat, deli meats, raw eggs, buffet salads and sprouts.
  4. Eat a healthy diet: It’s okay to give in to your pregnancy cravings sometimes, but try to eat a variety of healthy foods every day to ensure your baby gets all the nutrients it needs. Aim for three daily servings of protein, six servings of whole grains and legumes, three servings of green leafy or yellow fruits and vegetables, four servings of healthy fats, four servings of calcium and three servings of foods containing Vitamin C. It’s also important to eat some iron-rich foods every day. For more information, see Healthy Eating for Pregnancy.
  5. Exercise regularly: The American College of Obstetrics and Gynecology recommends that pregnant women exercise at a moderate intensity for 20 to 30 minutes most days of the week, unless they have pregnancy complications. Exercise can lower your risk of pregnancy and delivery complications, relieve lower back pain and constipation, ease stress, and make labor and postpartum recovery easier. If you were previously active, you can continue what you were doing at a moderate level (no high impact!). But if you didn’t exercise before, it’s not too late – talk to your healthcare provider about safe options for you.
  6. Do your Kegels: It’s never too early to start strengthening your pelvic floor – having strong muscles down there can prevent tearing during childbirth and postpartum incontinence. Identify the muscles that you use to stop your stream of urine. Squeeze and hold them for five seconds, and then release. Repeat 10 times. Work up to one set of 10 kegels three times a day. (Just don’t do your kegels while you’re urinating as this could cause urinary infections).
  7. Choose a healthcare provider: Whether you choose an OBGYN, a midwife and/or a doula depends on how you hope to give birth. An OBGYN – a highly trained medical doctor – is your best bet if you have pregnancy complications or plan on having a C-section. Midwives are also highly skilled at birthing babies, but they tend to offer a more natural approach with fewer medications and interventions. You can also choose to have a doula (in addition to your OBGYN or midwife) to offer you emotional and physical support throughout labor.
  8. Schedule your first prenatal visit:You should plan to see your doctor when you’re about eight weeks pregnant. They will ask about your medical history and perform a physical exam, including blood tests, a pap smear and possibly an ultrasound to check on the baby and confirm your due date. This appointment is a good time to ask any questions or raise any concerns you might have.
  9. Get first-trimester genetic tests done (if you wish): Your doctor may suggest that you undergo a genetic screening test to determine your risk of having a baby with a chromosomal or congenital abnormality such as Down syndrome or spina bifida, particularly if you have risk factors such being over 35 or a family history of genetic problems. You may be advised to have a non-invasive test such as a nuchal translucency (NT) scan between 11 and 13 weeks or non-invasive prenatal testing (NIPT) any time after 10 weeks. But if you’re at high risk of having a baby with an inherited condition, your doctor might suggest chorionic villus sampling (CVS), a procedure in which a needle is inserted into your abdomen and a tissue sample from the placenta is removed and analyzed. If your tests come back positive, further tests such as an amniocentesis may be required during your second trimester. While genetic tests are standard these days, you’re not obligated to have them.
  10. Check your health insurance plan: Find out as early as possible how much of your pregnancy and childbirth costs are covered by your health insurance so you can budget to cover the rest. Find out more here.
  11. Decide when you’ll announce the big news: Many women tell close family and friends that they’re pregnant early on, but wait until the risk of miscarriage drops at 12 weeks to announce it to the rest of the world. You may choose to wait even longer to tell your workplace if you’re unsure about how long you plan to be on maternity leave or whether you plan to return to work at all. You don’t have to announce it until you feel ready – or you can’t hide your tummy anymore!


Your baby’s growth

In the first five weeks of pregnancy, your baby will transform from a fertilized egg (zygote) into a hollow ball of cells (blastocyst) which will then implant in the wall of the uterus and become an embryo.

By the end of the embryonic stage at week 10, most of the important organs are completely formed, including the heart, nervous system, muscles, sexual organs, arms, legs and face. Only the brain and spinal cord continue to form and develop until birth.

By week 11, your baby makes the leap into the fetal stage and starts to form fingernails and toenails. At the end of the first trimester, your baby will measure three to four inches and weigh one ounce – the size of a lemon!