The First Trimester of Pregnancy

Pregnancy is a huge process. The moment of conception is a miracle all on it’s own considering the probability of one sperm fertilizing 1 egg. Conception can only happen within 2 days of ovulation. Those 2 days are very busy for the sperm that is traveling past the acidic cervical mucous up through the uterus to where they find the egg. By that time the number of sperm has decreased to about 200 and only one (or two in the chance of twins) will make it through the egg to fertilize it. What are the chances? It’s like hitting the lottery if you really think about it.

Congratulations you’re pregnant! The first trimester of pregnancy is full of change and development. The fertilized egg is finding its place in the uterus where it will plant itself in the lining which is why many women experience implantation bleeding. It can easily be mistaken by menstrual blood but much more light in color and will only last about a day if that. By this time you should avoid any medications that you’ve been taking. You will not be aware that you are pregnant around the 4th week and a huge amount of changes have already taken place.

The egg has split into a ball of cells called the blastocyst. The placenta is also at work making maternal blood to feed the baby. The Blastocyst is splitting into 3 sections that will later become the ectoderm, endoderm and mesoderm. The ectoderm forms the skin, nervous system and hair of your baby. The endoderm will become the gastrointestinal tract and other organs such as the liver, thyroid and pancreas. The mesoderm will create the skeletal system, blood system and connective tissues. Amazing to know all of this is going on and it’s going almost un-noticed in a woman’s body.

Around week 5 is when you will probably notice oops! I missed my period! Your breasts are tender, you’ll be urinating more frequently and you may even experience nausea also known as morning sickness. Morning sickness however can be experienced through out the day not just in the morning. By this time your baby your baby is called an embryo. It’s about 1/16th of an inch long and can hardly be seen with the naked eye. The spinal cord and heart have begun its development and if you were able to see it under a microscope you can see a tail which is the spinal cord forming.

At 6 weeks you can see a little weight gain around the midline and you may even feel dizzy if you stand up for too long. Your vulva may even turn a different color due to the extra blood circulating which can make a cool show and tell time with your partner for a few laughs and giggles. The baby’s heart starts beating around this time which is very exciting. Some people consider it to be officially alive at this time while others believe a baby is alive once the cells start to form at the moment of conception. The baby’s size has more than doubled to ½ an inch. It’s also growing little nubs where the arms and limbs will later develop.

By week 13 your baby has developed the vocal chords, organs are functioning, and the baby’s bone marrow is developing red blood cells, and is even growing hair. The uterus is about the size of a grapefruit. The 13th week ends the first trimester, a wonderful time of growth and development for you and your baby.

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Scroll to Top