Your Baby in the 1st Trimester

Week 1: Your period starts and your menstrual cycle begins

Week 2:

• The lining of your uterus begins to build up in order to prepare for a fertilized egg to implant.
• Your cervical mucous develops and egg white-like consistency.
• Ovulation occurs. 

Conception has occurred! Your 1st Trimester now begins!

Week 3: The egg is now fertilized by the sperm. At the end of the week the fertilized egg will embed itself in the lining of your uterus and divide. One part will become the placenta and the other will become the embryo.

Week 4:

• Amniotic fluid is now being produced.
• The fetus's eyes are starting to develop.
• At the end of the week the umbilical cord will start forming. This will be your baby's lifeline! 
• You've finished your first month! You may not even know you're pregnant yet.

Month 2 of Pregnancy

Week 5: 

• The embryo looks like a tadpole - even has a tail. Its around .05 inches (the size of an apple seed).
• Heart is starting to take shape. The circulatory system is the first to be in operation. The heart is about the size of a poppy seed and its already beating. 
• The neural system is developing, which will become the brain and spinal cord. Right now the neural tube is open. 
• Its a big week for the development of the muscles, bones, spinal cord, and heart, as well as other major organs.
• Hands are starting to appear.

Week 6:

• The jaws, cheeks, and chis are starting to be made. There are also little indents where the ears will be. 
• Small black dots set the place for the eyes. 
• A small bump on the front of the face is where the nose will be. 
• Also taking shape: kidneys, liver, and lungs. 
• The neural tube has closed. 

Week 7: 

• The embryo is 10,000 times bigger than it was at conception. Somewhere around .4in - .5in, it is now around the size of a blueberry. The "tail" is starting to disappear. 
• Mouth and tongue are forming, along with the arm and leg buds, which are beginning to sprout into paddle-like appendages and divide into hands, arms, legs, knees, shoulders, and feet. 
• Kidneys are now in place and in about a week they will produce urine.
• Eyes are continuing to develop and will begin to develop pigment.

Week 8:

• The embryo is around 1/2 inch - 1 1/4 inches now...about the size of a large raspberry or large grape.
• The skin is see through right now.
• The teeth, palate, and larynx are beginning to take shape.
• Lips, nose, eyelids, legs, and back are taking shape. 
• It has begun to make movements! Things like twitching of the trunk and limb buds, but its too tiny for Mom to feel.

Month 3 of Pregnancy
Week 9:

• No longer called an embryo, now you call it a fetus.
• It is around and inch long now.  
• Tiny muscles are starting to form and you can hear the heartbeat. 
• Only the outer ear is fully formed, but not in its final position. 
• The nose protrudes from the face and has a shape to it. 
• The mouth and lips are almost completely developed. 
• There is no longer a yolk sac; the placenta is now fully functioning. 
• The fingers and toes have lengthened and separated. The wrist has formed and is now able to bend. 
• The lower limbs are now flexed at the hip and knee joints so the baby looks like it's crossing it's legs.
• The eyelids have formed, but will stay closed until 26 weeks.
• The uterus is enlarging and lifting upward and out of your pelvis.

Week 10:

• The fetus is around 1 1/2 inches long now. 
• The amniotic sac has formed around the fetus. This fluid will help protect the fetus from harm and helps with temperature control. 
• All of the major organs have formed.
• Bones and cartilage are forming.
• Tiny buds of baby teeth are forming under the gums.
• If your fetus is a boy, he is already producing testosterone and his scrotum is forming.

Week 11:

• The fetus is just over 2 inches now and appearing more human-like.
• Hair follicles are forming and fingernail and toenail beds are beginning to develop.
• Ovaries and testicles are fully formed and the external genitalia are developing, but it's still too early to know the sex.
• The nasal passages are open.
• There is a tongue and palate in the mouth.
• There are visible nipples.
• Fetus can bring his/her hands to its face now.

Week 12:

• Fetus is now around 2 1/2 inches long.
• The pituitary gland has started producing hormones.
• The digestive system is beginning to practice contraction movements.
• Bone marrow is making white blood cells.
• The eyes are moving closer together, into their final positions. The face is properly formed.
• Blood has started to circulate through the umbilical cord, carrying oxygen and nutrients from the placenta to the fetus and carrying away waste produces.
• Urine produced by the kidneys is excreted into the amniotic fluid.