4 Weeks Pregnant

Learn what's happening in week 4 of pregnancy and find out how your baby is developing.

In the fourth week of pregnancy, many women still don't know they are pregnant. Your baby is currently smaller than a tiny seed and is called a blastocyst. The blastocyst splits to from the placenta and the embryo.

Your baby's body parts start to develop in week four. The fourth week also marks the beginning of the embryonic period when all of your baby's organs will begin to develop.

What happens in your body in pregnancy week 4?

4 Weeks Pregnant

You may be suspecting you're pregnant and trying to calculate your due date. The blastocyst that will develop into your baby has completed its six-day journey to your uterus. The tiny ball of cells burrows into your uterine lining making that unbreakable connection to you that will last the next eight months. Once it's settled in its new home, the blastocyst will split into two groups: the embryo and the placenta which is your baby's lifeline that transfers all the needed nutrients to your baby.

Changes in Your Body at 4 Weeks Pregnant

Many women will feel some pregnancy symptoms at 4 weeks, but they are convinced that their period is about to arrive. Some of the most common early signs of pregnancy that appear in the 4th week of pregnancy may include sore breasts, bloating, light spotting and fatigue.

Your blood volume will increase significantly during the fourth week so that your little one receives enough blood supply. Your kidneys have to work harder to process the extra blood and this will result in frequent urination which is one of the most common symptoms of pregnancy. Your heart also works harder to pump all the extra blood which may lead to tiredness, one of the first signs of pregnancy. The increased levels of pregnancy hormones estrogen, progesterone and hCG are responsible for all the signs of pregnancy and the changes in your body.

Your Baby at 4 Week of Pregnancy

In week four of pregnancy, the embryo grows and develops inside the lining of your womb. The outer cells form bonds with your blood supply while the inner cells form into three distinct layers of cells. The inner layer known as endoderm will become the breathing and digestive systems of the baby, including the stomach, lungs, gut, and bladder. The middle layer - mesoderm, will become the heart, muscles, bones. and blood vessels of the baby. The outer layer also known as ectoderm will become the brain, the nervous system, eyes, skin, and nails.

The embryo is surrounded by the fluid inside the amniotic sac. The outer layer of this sac develops into the placenta and cells from the placenta grow deep into the wall of the womb, creating a rich blood supply. In this way, your baby will receive all the oxygen and nutrients it needs to survive.

Pregnancy Week 4 Tips

If you have taken a positive pregnancy test, schedule your first prenatal appointment with your doctor. See a doctor as soon as possible after you find out you are pregnant to begin getting prenatal care. Your health care provider will discuss the importance of prenatal vitamins and proper nutrition. Your first prenatal visit is also as good time to discuss your work environment, use of medications, sex during pregnancy and exercise.

Avoid alcohol and cigarettes and eat lots of fruits and vegetables rich in folic acid. Regular exercise can help to manage pregnancy-related weight gain.