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Changes in your body

Many women 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.

Learn more about what you should expect in week five. (Psst! For week-by-week pregnancy guidance, tips, and more, sign up for our I’m Expecting newsletter.)

Your baby

The fifth week of pregnancy marks the start of the embryonic period. This is when your 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 week or two. 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. The National Health Service estimates that your baby is about 2 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.

Twin development at week 5

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. You may have cramping and bleeding, or you may have no symptoms at all.

5 weeks pregnant symptoms

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

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 symptoms in week five of pregnancy:

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 the sixth week of pregnancy, some women 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 an extreme form of morning sickness. It sometimes requires in-patient treatment within a hospital setting.

2. Lightheadedness

Your blood pressure tends to run lower than normal 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 fluids.

4. Abdominal cramps

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

Coughing, sneezing, or changing positions can make these cramps more noticeable.

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.

Some women with healthy pregnancies have spotting for the entire first trimester.

6. Fatigue

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

Fatigue during pregnancy is most common during the first trimester, but some women 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 your 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 to relieve or eliminate constipation.

10. Increased vaginal discharge

Vaginal discharge during pregnancy can be normal. 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 normal to feel a variety of emotions, 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.

Warning signs of a miscarriage

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

The most common sign of a miscarriage is vaginal bleeding. The bleeding tends to be heavier than spotting, and it may contain clots. You may also have abdominal or pelvic cramps and back pain. Call your doctor if you experience any bleeding during pregnancy.

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

Symptoms of an ectopic pregnancy include vaginal bleeding, pelvic pain or cramping (possibly on one side), shoulder pain, and dizziness or fainting.

Call your doctor right away if you have symptoms of an ectopic pregnancy.

5 tips for a healthy pregnancy

  1. If you haven’t already done so, schedule your first prenatal doctor visit. Going to checkups is a must for a healthy pregnancy. Your doctor will let you know what actions to take to keep your baby healthy for nine months.
  2. 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 are vital for proper brain and eye development in your baby. They also help your breast milk to be more nutritious.
  3. Add healthy foods to your diet like fruits, vegetables, whole grains, lean proteins, beans, nuts, and dairy. Maintaining a healthy diet is important for your baby’s health.
  4. Make sure your proteins are fully cooked, and avoid high mercury seafood and unpasteurized dairy to prevent infection in your growing baby.
  5. Don’t smoke cigarettes, drink alcohol or excessive caffeine, or use illegal drugs. These can harm your baby. Some prescription and over-the-counter medications also aren’t safe during pregnancy. Let your doctor know about all medicines, vitamins, supplements, and herbs you take.
Weight Gain at Week FiveYou may have some bloating at week five, which could contribute to a little weight gain. In general, though, you shouldn’t expect to gain any weight this early in your pregnancy.