At 5 weeks pregnant, your little one truly is little. At no larger than the size of a sesame seed, they’ll have just begun forming their first organs.

You might start to feel new things, too, both physically and emotionally. Let’s learn more about what you can expect in week 5 of your pregnancy.

5 weeks pregnant: What to expect

  • You might have PMS-like symptoms such as fatigue, sore breasts, and morning sickness.
  • Your baby is very tiny, only about 2 millimeters.
  • Your baby’s heart might start beating now, though it may not be detected by ultrasound for another couple of weeks.
  • You’ll want to learn about the signs of miscarriage and ectopic pregnancies.

Many people first learn that they’re expecting during the fifth week of pregnancy. By now you have missed your menstrual period, and a pregnancy test should have come back positive.

You may be dealing with lots of new emotions, feelings, and concerns. Not to worry, though — we’ve got you covered with all the details of this amazing time.

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Illustration by Alyssa Kiefer

The fifth week of pregnancy marks the start of the embryonic period. This is when baby’s body systems and structures begin to form, such as the heart, brain, and spinal cord.

Your baby’s heart beats at a steady rate now, though it may not be detected by ultrasound for another 1 or 2 weeks. The placenta is also starting to develop.

At this stage, your baby doesn’t look like a baby yet. The embryo is growing quickly, but it’s still very small, about the size of a pen tip or a sesame seed. Around this time, baby initially measures just 2 to 3 millimeters.

Your body is gearing up to go through big changes, too.

Pregnancy hormone levels are rapidly rising, and your uterus will begin to grow. You won’t look pregnant for a couple more months, but you may start to experience symptoms now.

If you’re carrying multiples, you may be able to detect your babies through an early ultrasound during week 5.

Your babies are measured in millimeters at this point, but you might see two gestational sacs or even a couple of tiny fetal poles as the week goes on.

Occasionally, you’ll detect two gestational sacs at this early stage, but only one baby at a later ultrasound. This is called vanishing twin syndrome. There’s often no clear reason for the loss, per 2021 research. You may have cramping and bleeding, or you may have no symptoms at all.

Pregnancy checklist at 5 weeks

  • Choose a pregnancy professional. If you don’t already have an OBGYN to guide you through your pregnancy, start doing research now to find one you feel comfortable with.
  • Start on a prenatal vitamin. If you’re not already taking a daily prenatal vitamin, now is a good time to start. Folic acid, a B vitamin essential for baby’s health, is usually higher in prenatals. You’ll want about 400 mcg per day.
  • Limit caffeine. Even as little as half a cup of coffee a day may affect baby’s birth weight, experts say. This can increase their risk of complications as an infant.
  • Consider a pregnancy tracker app. There are lots of free apps available that can provide of information during your pregnancy — everything from baby’s size at each week to educational articles for your health and baby’s health.

Pregnancy symptoms are unique and unpredictable. Two people can each have healthy pregnancies without any of the same symptoms. Likewise, you may have bad nausea in your first pregnancy, but no morning sickness in a later pregnancy.

The swiftly rising levels of the hormones human chorionic gonadotropin (hCG) and progesterone are responsible for many of the pregnancy symptoms you experience.

You can expect any of the following week 5 pregnancy symptoms:

1. Morning sickness

Don’t be fooled by the word “morning.” Nausea and vomiting can happen at any time during the day.

While morning sickness typically begins during week 6 of pregnancy, some people experience it earlier.

Eating several small meals throughout the day (instead of two or three big meals) may help to relieve these symptoms.

Call your doctor if you can’t keep any food or liquid down. This may be a sign of hyperemesis gravidarum, which is a rare disorder that involves continual nausea and vomiting during pregnancy. It sometimes requires in-patient treatment at a hospital.

2. Lightheadedness

Your blood pressure tends to run lower than usual during pregnancy. This can cause dizziness and even fainting.

If you feel dizzy, sit down if you’re standing or pull over if you’re driving.

3. Frequent urination

As your uterus expands, it can press against your bladder. This will likely cause you to need to urinate more frequently.

Go when you have the urge so that you avoid bladder infections. Drink plenty of water to avoid becoming dehydrated.

4. Abdominal cramps

You may experience mild cramping or bloating. This can be caused by the egg implanting or from your uterus stretching.

While mild cramping shouldn’t cause alarm, contact your doctor immediately if you experience severe pain that doesn’t go away.

5. Vaginal bleeding

Light bleeding, also known as spotting, around the time of your missed period is usually considered implantation bleeding.

While spotting can be caused by many factors, always let your doctor know if you notice any spotting or bleeding at any time during pregnancy.

6. Fatigue

As your progesterone levels increase, you may find yourself feeling sleepy and losing energy.

Fatigue is most common during the first trimester, but some people will experience fatigue throughout their pregnancy.

7. Breast changes

You may experience tender, sore, swollen, or fuller breasts as your hormone levels change. This is one of the earliest symptoms of pregnancy and may appear soon after conception.

8. Food cravings and aversions

Your changing hormones can lead to a change in your appetite.

You may find yourself avoiding foods you used to enjoy, or you may start craving foods you don’t commonly eat. You can begin experiencing food cravings and aversions early on in your pregnancy.

9. Constipation

Your food will start moving more slowly through your digestive system to give nutrients more time to be absorbed into your bloodstream and reach your baby. This delayed transit can lead to constipation.

Eating more fiber and drinking lots of fluids can help relieve or eliminate constipation.

10. Increased vaginal discharge

Vaginal discharge during pregnancy may be expected. It should be thin, white, milky, and mild smelling.

If the discharge is green or yellowish, has a strong smell, or is accompanied by redness or itching, you should contact your doctor. This is likely a sign of a vaginal infection.

11. Mood swings

Pregnancy can cause a lot of emotions. Not only can the idea of a new baby cause emotional stress, but the changes in your hormones can also affect your emotions.

It’s perfectly fine to feel a variety of emotions from day to day — such as elation, sadness, anxiety, fear, and exhaustion. If these feelings are extreme or last more than a few days, consult your doctor right away.

According to The American College of Obstetricians and Gynecologists (ACOG), about 10 percent of pregnancies end in miscarriage.

Signs of a miscarriage include:

  • vaginal bleeding (the most common sign, which tends to be heavier than spotting and may contain clots)
  • abdominal or pelvic cramps
  • back pain

Call your doctor if you experience any bleeding during pregnancy.

An ectopic or “tubal” pregnancy is a pregnancy that grows outside the uterus, most often in the fallopian tube. This type of pregnancy isn’t viable and can be life threatening to the birthing parent.

Symptoms of an ectopic pregnancy include:

  • vaginal bleeding
  • pelvic pain or cramping (possibly on one side)
  • shoulder pain
  • dizziness or fainting

Call your doctor right away if you feel as though you are having symptoms of an ectopic pregnancy.

According to the ACOG, individuals who have a supportive partner are more likely to engage in healthier behaviors, and their babies are more likely to be born with lower rates of preterm birth and growth issues.

A few ways you can support your pregnant partner include:

  • Go with your partner to as many of their prenatal appointments as you can.
  • Eat and prepare nutritious foods for both of you, so your partner is not doing it alone.
  • Listen to your partner whenever they express their feelings regarding the pregnancy or birth, and know that mood shifts are a natural part of the process.
  • Be open to discussing both the positive and negative aspects of pregnancy and birth.

Educating yourself on the changes during each trimester and well as the symptoms associated with those changes, and what your partner may need during delivery and after delivery, are great ways to support them.

  • Schedule your first prenatal doctor’s visit. This is important to do if you haven’t already done so. Going to checkups is a must for a healthy pregnancy. Your doctor will let you know what actions to take to keep your growing baby healthy for 9 months.
  • Take a prenatal vitamin. Prenatal vitamins that contain high levels of folic acid may lower the risk of some birth defects. Many prenatal vitamins now provide omega-3 fatty acids DHA and EPA as well. These nutrients can be helpful for proper brain and eye development in baby, according to 2012 research. They can also help with the nutrition of breast milk.
  • Add nutrient-dense foods to your diet. This includes fruits, vegetables, whole grains, lean proteins, beans, nuts, and dairy. Maintaining a balanced, nutritious diet is important for your baby’s health.
  • Practice food safety. Make sure your proteins are fully cooked and avoid high mercury seafood and unpasteurized dairy to prevent infection in your growing little one.
  • Avoid substances that can harm baby. Don’t smoke cigarettes, drink alcohol or excessive caffeine, or use other substances like cannabis. There’s no safe amount of alcohol when pregnant. Some prescription and over-the-counter meds also aren’t safe during pregnancy. Let your doctor know about all medications, vitamins, supplements, and herbs you’re taking. Seek help if you need assistance with substance use.

Week 5 of your pregnancy is still early for the most dramatic changes and physical symptoms. But your teeny tiny baby is on their way to growing strong and healthy.

The decisions you make to take care of yourself and your little one this early on will directly impact all the factors later.

Make sure to see your doctor in order to understand the best choices to make for nutrition and lifestyle.