Pregnancy

Fetal development in the first trimester

Expectant parent with picture of ultrasound. Early pregnancy. 1st trimester

Follow this 3 part series to learn about your baby’s development throughout your first, second, and third trimester.

What do I need to know?

The early part of pregnancy, also called the first trimester is about 3 months long. It is an important time in pregnancy for your baby’s growth and development because all important structures and organs begin to develop during these first weeks.  Although it’s important to seek health care, eat well, be active and stay away from harmful environmental exposures before and throughout your pregnancy, it’s especially important during this time.

 

What’s happening and when?

Week

Highlights of Development

1

The 40 weeks in pregnancy are counted from the first day of your last period fetal development 1 month

2

An egg matures in one ovary and is released

3

The mature egg is fertilized by sperm

4

Implantation is complete by the end of this week

You will miss your period

5

The spinal cord and nervous system is developing fetal development 2 months

6

Eyes, ears, nose and the digestive system start to form

The heart starts to beat

7

Arms and legs start to form

8

The mouth is more developed and baby teeth are starting to form

9

Fingers and toes are growing fetal development 3 months

10

External genitals are starting to form

11

Your baby is kicking and moving around in your uterus

12

Lungs, stomach and intestines are taking shape

13

Fingernails and toenails are forming

The heart is completely formed

By the end of your first trimester, your baby is approximately 7.5 cm long and weighs 30g.

If you have any questions or concerns about your baby’s development, be sure to speak with your health care provider.  Next up is your baby’s development in the second trimester.

One thought on “Fetal development in the first trimester

Leave a Reply