Week 9: Embryo Becomes Fetus

Congratulations — this week marks an important transition! Your baby is now officially called a fetus instead of an embryo. All the basic organs are in place, and from now on it is all about growth and maturation. Although the baby is only the size of a grape — about 2.3 cm long and weighing approximately 2 grams — big things are happening in there.

This week the heart is fully developed with four chambers, the muscles are beginning to work, and the tiny embryonic tail has almost completely disappeared. The baby is starting to look more and more like a tiny human. It is a medical milestone marking that the most critical developmental stages have been passed.

For you, week 9 means you are well into the first trimester. Nausea may still be tough, but for many people the light at the end of the tunnel is beginning to show. The worst weeks are nearly over, and the second trimester — which many call the golden period of pregnancy — is approaching.

Baby's Development

From embryo to fetus: All essential organs have formed. Now they begin to grow, mature, and improve for the rest of the pregnancy
Heart has four chambers: The tiny heart beats with four chambers at approximately 170 beats per minute — almost double the rate of your own
Tiny muscles working: The very small muscles have started to work, and the baby can make tiny movements you cannot feel yet
Tail disappears: The small embryonic tail has almost completely gone, and the baby looks increasingly human
Genitals developing: The baby's genitals begin to take shape, but it is far too early to see the sex on an ultrasound
Joints more developed: Elbows, wrists, knees, and ankles are distinct, and the baby can bend arms and legs
Digestive system maturing: The intestines are growing rapidly and temporarily extend into the umbilical cord because there is not enough room in the abdomen
Size: The fetus is about 2–2.5 cm long (crown to rump) and weighs approximately 2 grams

The Transition From Embryo to Fetus

The transition from embryo to fetus in week 9 is a medical milestone.

In the embryonic phase (weeks 3–8), the focus is on organogenesis — the formation of organs. All the most important organs are established during this period. This is the phase when the risk of congenital malformations is highest, because the organs are forming.

In the fetal phase (week 9 to birth), the focus shifts to growth and maturation. The organs are in place, and now they need to grow, develop, and begin to function optimally.

This does not mean all risks have passed — the baby is still vulnerable to infections, medications, and substances. But the basic architecture is in place, and that is a significant milestone.

Baby's Movements

Even though you cannot feel it yet, your baby is already moving. The tiny muscles have started to contract, and the baby can make small jerks and movements with arms and legs. On an ultrasound, you can sometimes see the fetus stretch, bend, or even hiccup. These early movements are important for the development of muscles, joints, and the nervous system.

Most pregnant people do not feel fetal movements until weeks 16–22. First-time parents often feel movements a little later than those who have been pregnant before.

Your Body

Waist thickening: Even if you may not be showing yet, clothes may start to feel tighter around the waist. The uterus is now about the size of a large lemon
Mood swings: Hormones such as progesterone and estrogen can put you on an emotional rollercoaster. You may laugh one moment and cry the next
Vivid dreams: Many pregnant people experience unusually vivid or strange dreams, likely due to hormonal changes and lighter sleep
Breasts growing: Breasts can be tender and noticeably larger. It may be a good idea to get a supportive bra without underwire
Heightened sense of smell: Many notice that their sense of smell becomes stronger. Smells that were previously neutral can suddenly trigger nausea
Skin changes (acne): Hormonal changes can cause breakouts, even in people who normally have clear skin
Dizziness: Blood pressure can be slightly lower than usual, and you may experience dizziness, especially with quick movements

Your Blood Volume Is Increasing

Already in week 9, your body has started producing more blood. By the end of pregnancy, blood volume will have increased by almost 50 percent. This increase is necessary to supply the placenta and the baby with oxygen and nutrients.

It is one of the reasons your iron needs increase, and why you may experience heart palpitations and feeling warm. Some pregnant people notice they run warmer than usual, sweat more, or get breathless more easily. All of this is normal and is caused by the increased blood volume.

Good to Know

Your iron needs increase throughout pregnancy because your blood volume grows by up to 50 percent. According to WHO, pregnant people need approximately 27 mg of iron daily.

Good iron sources:

Lean red meat (beef, lamb)
Beans and lentils
Dark leafy greens (broccoli, kale, spinach)
Whole grains
Dried fruit (apricots, raisins)

Take iron with vitamin C (for example a glass of orange juice or some bell pepper) for better absorption. Coffee, tea, and dairy products slow iron absorption, so wait at least half an hour after an iron-rich meal before having these.

If you are struggling with nausea, ginger can help. Ginger tea, ginger biscuits, or fresh ginger in hot water is a safe and natural remedy for pregnancy nausea. Acupressure bands on the wrist can also bring relief for some people.

Try to maintain a calm and stable routine. Enough sleep and regular meals can make a big difference to how you feel. Go to bed early, and eat a small snack before sleeping to prevent nausea in the morning.

Caffeine should be limited to a maximum of 200 mg per day during pregnancy, according to WHO and major health bodies. This is roughly equivalent to one cup of filtered coffee. Be aware that tea, cola, energy drinks, and chocolate also contain caffeine.

Folic Acid Through the Entire First Trimester

According to WHO and ACOG, all pregnant people should take 400 micrograms of folic acid daily through the entire first trimester. Week 9 is in the middle of this important period, and it is critical to continue with the supplement.

Why Is Folic Acid Still Important in Week 9?

Even though the neural tube closed around weeks 6–7, folic acid continues to play an important role:

Cell division: The baby is growing rapidly, and folic acid is necessary for cells to divide normally
Red blood cells: Folic acid contributes to the formation of red blood cells, which is especially important now as your blood volume increases
DNA synthesis: Folic acid is essential for correct DNA copying during cell division
Preventing anemia: Adequate folic acid reduces the risk of pregnancy-related anemia

Foods Rich in Natural Folate

In addition to supplements, you can get folate from your diet:

Dark leafy greens: Spinach, kale, broccoli
Legumes: Beans, lentils, chickpeas
Citrus fruit: Oranges, clementines, grapefruit
Whole grains: Bread, pasta, oatmeal with whole grains
Eggs: Especially the yolk is rich in folate

Remember that folate from food alone is usually not enough — supplements are recommended in addition, as per WHO guidelines.

NIPT and Early Prenatal Screening

From weeks 9–10, you can begin to think about NIPT (Non-Invasive Prenatal Testing), a blood test that analyzes free fetal DNA in your blood:

What it tests: Trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome)
Accuracy: Over 99 percent for trisomy 21
Availability: NIPT is available in many countries and healthcare systems — ask your midwife or doctor
Timing: Can be taken from week 10, but you can discuss this with your midwife or doctor now
Voluntary: You have no obligation to take the test. You will receive thorough information and counseling before deciding
Cost: Varies by country and healthcare system — some offer it free of charge, others as a paid option

Talk to your midwife or doctor if you would like more information about prenatal screening.

Exercise in Week 9

Even though you may feel tired, moderate physical activity is safe and recommended. According to WHO and major health bodies, pregnant people should be physically active for at least 150 minutes per week at moderate intensity:

Walking: The simplest and most accessible option. Fresh air can also help with nausea
Swimming: Gentle on the joints and provides good cardiovascular fitness. The water supports your weight and gives a feeling of weightlessness
Yoga: Prenatal yoga strengthens the body and provides relaxation. Avoid positions that put pressure on the abdomen
Pelvic floor exercises: Important throughout pregnancy. Aim for 3 sets daily
Moderate strength training: Safe with appropriate adjustments for pregnancy

Avoid contact sports, activities with a risk of falling, and exercise that makes you very breathless. Listen to your body and reduce intensity if you feel nauseous or tired.

Benefits of Exercise in Pregnancy

Regular moderate exercise in pregnancy can:

Reduce the risk of gestational diabetes
Prevent back pain and pelvic pain
Improve sleep quality
Reduce the risk of high blood pressure
Contribute to faster recovery after birth
Improve mood and energy levels

For Your Partner

Show understanding for intense emotions. Mood swings are hormonally driven and will settle down with time
Consider starting a shared pregnancy journal or taking weekly photos to document the journey together
Stock up on foods that are easy to eat when nauseous — crackers, fruit, yogurt, and soups
Read about prenatal screening together so you can make informed decisions as a couple
Follow the baby's development in the pregnancy timeline together
Come along to prenatal appointments. It strengthens the bond and gives a better understanding of what is happening

Tips for Week 9

Wear comfortable clothes: Soft trousers with an elastic waistband give good comfort as the waist grows
Talk to someone you trust: If feelings become overwhelming, it can help to talk with a friend, partner, or midwife
Limit caffeine: Keep below 200 mg daily. Switch to decaf or herbal tea
Eat iron-rich food: Lean meat, beans, and dark leafy greens combined with vitamin C for better absorption
Stay hydrated: Drink at least 1.5 liters of water daily
Keep taking folic acid: Stay on your daily folic acid supplement through the whole first trimester

When to Contact a Doctor

Contact your doctor or midwife if you experience:

Bleeding heavier than light spotting
Severe pain in the lower abdomen, especially on one side
Dizziness or fainting that does not resolve
Nausea making it impossible to keep food or fluids down for more than 24 hours
Fever over 38°C (100.4°F)
Pain or burning when urinating

Light spotting in the first trimester is common and usually harmless, but always mention it to your midwife or doctor at the next appointment. Spotting in early pregnancy can be caused by hormonal changes, implantation bleeding, or contact bleeding after sex. It is rarely a sign of something serious, but contact your doctor for reassurance.

Did You Know?

From this week, the baby is officially called a "fetus" instead of "embryo." The transition marks that all basic organs have formed, and now it is about growth and maturation.
The tiny heart now beats at approximately 170 beats per minute — nearly three beats per second! The heart rate will gradually slow through pregnancy to approximately 120–160 at birth.
The baby can now make small movements with arms and legs, but is still far too small for you to feel anything. These movements are important for the development of muscles and joints.
The small embryonic tail that was visible earlier is now almost completely gone. The baby looks more and more like a tiny human.
Although the genitals are beginning to develop, it is impossible to see the sex on ultrasound in week 9. The sex is determined at fertilization by the X or Y chromosome from the father.
The baby's intestines are so long that they temporarily protrude into the umbilical cord. They will retract back into the abdomen around week 12 when there is enough space.

Frequently Asked Questions About Week 9

Are mood swings normal at this stage?

Yes, mood swings are completely normal and very common in the first trimester. They are caused by the major hormonal changes in your body, especially rising levels of progesterone and estrogen. You may experience everything from intense joy to inexplicable crying in a short space of time. This usually improves in the second trimester when hormone levels stabilize.

How much weight is it normal to gain in the first trimester?

In the first trimester, it is normal to gain between 0.5 and 2 kg. Some people actually lose weight due to nausea. Both are usually completely fine. The largest weight gain comes in the second and third trimesters. Recommended total weight gain depends on pre-pregnancy BMI — talk to your midwife or doctor if you have concerns.

Is it safe to travel in early pregnancy?

For most people it is safe to travel in the first trimester, including by air. Remember to drink enough water, move around regularly on long journeys, and have travel insurance that covers pregnancy. Avoid travel to areas with risk of malaria or Zika virus. Talk to your doctor if you are planning long trips.

Why am I having such vivid dreams?

Vivid and strange dreams are very common in pregnancy. It is likely caused by a combination of hormonal changes, lighter sleep, and the fact that you wake more often during the night (and therefore remember dreams better). It is completely harmless, even if the dreams can be quite intense. Many dream about the baby, birth, or becoming a parent.

What is the difference between nausea and hyperemesis?

Normal pregnancy nausea is unpleasant but manageable — you can eat and drink something. Hyperemesis gravidarum is a serious condition where you vomit so much that you cannot keep food or fluids down, and you may lose weight and become dehydrated. Hyperemesis affects approximately 1–3 percent of pregnant people and requires medical treatment. Contact your doctor if you cannot keep fluids down for more than 24 hours.

Can the baby feel pain in week 9?

No, in week 9 the nervous system is too immature to process pain signals. Pain receptors and the nerve pathways required for the experience of pain develop gradually throughout pregnancy. Most experts believe that the ability to experience pain is not present until after week 24, when the brain's pain centers are more developed.

What is NIPT, and should I have the test?

NIPT (Non-Invasive Prenatal Testing) is a blood test that can be taken from week 10. It analyzes free fetal DNA in your blood and can with over 99 percent accuracy detect trisomy 21 (Down syndrome), trisomy 18, and trisomy 13. It is a voluntary test, and it is an entirely personal choice whether you wish to take it. Talk to your midwife if you would like more information.

Can illness in week 9 harm the baby?

A common cold is not dangerous for the baby. Your body protects the fetus well. For fever, take paracetamol (acetaminophen) to keep the temperature down, as prolonged high fever can affect fetal development. Contact your doctor if you:

Have a fever over 38°C (100.4°F) lasting more than a day
Have flu-like symptoms
Have a rash or signs of infection

Avoid ibuprofen during pregnancy. Paracetamol (acetaminophen) is safe at recommended doses.

Is it safe to have sex in week 9?

Yes, sex is safe throughout pregnancy for most pregnant people. The baby is well protected by amniotic fluid and the cervix. You may experience light spotting after sex, which is caused by increased blood flow to the cervix and is usually completely harmless. Talk to your doctor if you are worried or have had complications.

Next week: Fingers and toes are fully developed, and the brain produces neurons at a record pace!