Pregnancy Week 3
This week, fertilization may occur as the egg and sperm come together to create the first cell of your developing baby. Although you may not feel pregnant yet, important changes are beginning at the cellular level.
Your Baby This Week
Fertilization Has Occurred
If sperm meets the egg during your fertile window, fertilization can occur during week 3. The fertilized egg, now called a zygote, begins dividing into more cells as it travels through the fallopian tube toward the uterus.
The developing cluster of cells will continue to grow and eventually become an embryo after it reaches the uterus.
A New Beginning
The fertilized egg contains genetic material from both the egg and sperm. This genetic information will guide your baby’s development throughout pregnancy.
Tiny Beginnings
The fertilized egg is rapidly dividing into more cells as it travels toward the uterus. It is still too small to be seen without a microscope.
Your Body This Week
Your body is beginning to respond to the possibility of pregnancy, although you may not notice any obvious changes yet.
Fertilization
The egg and sperm may combine in the fallopian tube, creating a single cell that will begin dividing.
Cell Division
The fertilized egg continues to divide as it moves toward the uterus, forming a growing cluster of cells.
Hormonal Changes
After ovulation, progesterone levels rise and help maintain the uterine lining in preparation for possible implantation.
Preparing for Implantation
The developing cell cluster is traveling toward the uterus, where it may attach to the uterine lining during the coming week.
Tips for week 1
- Continue taking a prenatal vitamin containing 400 mcg of folic acid.
- Eat a balanced diet with plenty of fruits, vegetables, whole grains, and protein.
- Stay hydrated throughout the day.
- Avoid alcohol, smoking, and recreational drugs.
- Limit caffeine to the recommended amount if you are trying to conceive or may be pregnant.
- Get enough sleep and allow your body time to rest.
- Continue regular, moderate physical activity if it is comfortable for you.
- Don't worry if you do not feel any pregnancy symptoms yet it is still very early.
Nutrition This Week
Your body needs a variety of nutrients as the earliest stages of pregnancy begin. Focus on nutritious foods and continue taking your prenatal vitamin.
Folate-Rich Foods
Healthy Fats
Protein Rich Foods
Fruits & Vegetables
Calcium Sources
Stay Hydrated
Nutrition Tip
Keep taking your prenatal vitamin with folic acid every day. Early pregnancy is a particularly important time for adequate folic acid because the neural tube begins developing very early.
Frequently Asked Questions
Is my baby developing during Week 3?
If fertilization has occurred, the fertilized egg is beginning its earliest stages of development. It is still extremely small and is not yet an embryo implanted in the uterus.
When does fertilization happen?
Fertilization usually occurs within about 24 hours after ovulation if sperm is present. The exact timing varies depending on when ovulation occurs.
Can I feel pregnancy symptoms during Week 3?
Most people do not notice clear pregnancy symptoms this early. Some may experience mild changes, but many have no symptoms at all.
Has implantation happened during Week 3?
Implantation usually occurs several days after fertilization, often around the end of the third week or during the fourth week of pregnancy. Timing can vary.
Can I take a pregnancy test during Week 3?
It is often too early for a home pregnancy test to reliably detect pregnancy during week 3. Pregnancy tests are generally more accurate after a missed period.
Week by Week
Explore your pregnancy journey week by week.
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