WEEK 3 / 40 · Trimester 1

Pregnancy Week 3

Fertilization week

About 37 weeks until birth

The first weeks
  1. 1Preparation
  2. 2Ovulation
  3. 3Fertilization

Pregnancy is counted from the first day of your last period; there is no embryo yet in the first three weeks. The first size comparison starts in week 4.

The big meeting has happened! Fertilization has occurred and the cell (zygote) has begun dividing rapidly — far too small to see.

What's Happening With Your Baby This Week?

  • Gender, eye color, hair color, and all genetic codes (DNA) were determined at the moment of fertilization.
  • The zygote rapidly divides into a 2, 4, 8, then 16-cell structure (morula) as it travels through the tube.
  • Around day 5, it reaches the blastocyst stage; the inner cell mass will form the baby, while the outer layer will become the placenta.
  • The fertilized egg makes a journey of about 3-4 days from the fallopian tube toward the uterus.
  • The blastocyst is preparing to attach to the uterine wall (implantation); this process may cause light spotting.

This Week's Tips for Mom

  • Drinking plenty of water is very important; your daily fluid intake is crucial for cell division and increasing blood volume.
  • You can eat small but frequent meals; keeping blood sugar stable can help ease early nausea.
  • Light walks can support your blood circulation; 20-30 minutes a day will be sufficient.
  • It's safest not to use any medications without consulting your doctor, as some can be harmful during pregnancy.
  • Light spotting (implantation bleeding) can happen; but if bleeding soaks a pad or you have severe, one-sided belly pain, contact your doctor or go to the emergency room right away.
Tip of the day: If mild nausea begins, ginger tea can be a wonderful natural remedy. Cold lemon water or peppermint tea are also effective methods for relieving nausea.
This content is for informational purposes only and is not a substitute for medical advice. Length and weight values are averages; every baby grows at their own pace.

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