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First Trimester 5 weeks pregnant

Pregnancy Week 5 - Heart Tube Forms & Morning Sickness

At 5 weeks, your embryo is growing rapidly. The heart tube has formed and will begin beating soon. The neural tube, which becomes the brain and spinal cord, is closing. Morning sickness and other early pregnancy symptoms may become more noticeable.

Sesame seed
Baby Size
0.3 cm
Length
Less than 1 gram
Weight
Week 5
of 42
Baby Development This Week

This is a critical week for your baby's development. The heart tube has formed and will begin to beat this week, though it is not yet audible. The neural tube is closing, which will become the brain and spinal cord. Three distinct layers of cells are forming: the ectoderm (nervous system, skin, hair), mesoderm (muscles, bones, circulatory system), and endoderm (lungs, intestines, bladder). The placenta is beginning to function.

Changes in Your Body

Morning sickness may begin this week, though it can strike at any time of day. Rising hCG levels are responsible for nausea and food aversions. Your breasts may feel increasingly tender and swollen. You might feel more tired than usual as your body works hard to support the pregnancy. Mood swings are common due to hormonal changes.

Common Symptoms at Week 5
Nausea (morning sickness)Breast tendernessFatigueFrequent urinationFood aversionsMood swings
Tips for Week 5
  • Eat small, frequent meals to manage nausea and keep blood sugar stable.
  • Keep crackers by your bedside to eat before getting up in the morning.
  • Stay hydrated by sipping water throughout the day.
  • Get plenty of rest and do not push yourself too hard during this exhausting time.
When to Call Your Doctor

If you cannot keep any food or fluids down, contact your healthcare provider. Severe vomiting may be a sign of hyperemesis gravidarum, which requires medical treatment.

Frequently Asked Questions — Week 5

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