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What To Expect In Your 5th Week Of Your Pregnancy


You are now 5 weeks pregnant and have entered what is called the embryonic period of development; during this time your baby’s major organ systems and structures will develop. You will likely have missed your period and a pregnancy test should be taken. You may also be noticing some early symptoms of pregnancy including mood swings, breast tenderness, exhaustion, waves of nausea and urinary frequency.

Your hormones

There are various hormones circulating throughout your body to maintain and support your pregnancy.

  • Estrogen: the hormone estrogen is produced to maintain your progesterone and hCG levels
  • Progesterone: the hormone progesterone has many responsibilities. Not only is it responsible for maintaining placental function, but it is also responsible for inhibiting uterine contractions and stimulating breast tissue growth
  • Human Chorionic Gonadotropin (hCG): the hormone hCG is also vital to the health of your pregnancy as it supports the primitive means of nourishment to your baby, the corpus luteum. At the end of the first trimester, the placenta will be fully functional. HCG is additionally responsible for maintain adequate levels of progesterone.

Baby’s development at 5 weeks pregnant

Your baby is growing at a rapid pace with several cell types and organs starting to develop including the blood cells, kidney cells, nerve cells, brain, spinal cord, heart, and gastrointestinal tract.

Additionally, the neural tube responsible for forming the brain, spinal cord, nerves and backbone is developing from the ectoderm, which will also form the skin, hair, nails, mammary and sweat glands and tooth enamel.

Your baby’s heart and circulatory system will form from the mesoderm, which will also form muscles, cartilage, bone and subcutaneous tissues.2 Your baby’s heart, which is now divided into two “tubes,” may be visible beating on an ultrasound.

This time gives way to the development of the lungs, intestines, urinary system, thyroid, liver and pancreas from the endoderm.

While these organs are developing, the primitive placenta and umbilical cord are functioning and are providing your baby with the nourishment and oxygen necessary for survival.

Your growing baby is vulnerable to the effects of various elements including the use of certain medications, illegal drugs, excessive alcohol use and infections (rubella, etc.). The effects of these elements can lead to birth defects.


Baby’s size at 5 weeks pregnant

Your baby is now the size of a sesame seed and resembles more of a tadpole than a baby!


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