At 13 Weeks Pregnant Your Baby has Developed Several Organs


At 13 weeks pregnant, your baby now measures 2 1/2 to 3 inches long, about similar to the size of a pea pod and weighs about one ounce. Though at this moment, he is still quite small, your baby is rapidly growing and learning some tricks such as leg kicking, head turning, swallowing, yawning as well as hiccupping, just to show you!

You are also about to enter your second semester when you are 13 weeks pregnant. This week is your lucky week since some early pregnancy symptoms begin subsiding. However, this does not apply to all pregnant women and that the risk of miscarriage is greatly reduced.

Your Baby’s Development this Week

Internal changes

13 weeks pregnant

Today’s significant development is his skeletal formation and is beginning to harden. The bones are building up on your baby’s arms and legs, along with his clavicle or the collarbone and femur or the thigh bone which were the first ones seen developing during this week. 

Your baby’s body organs including the stomach and bowel are shaping. The intestines are also growing and are now moved – they’ve been placed in the abdomen. Veins are spreading and the organs, which have now completed forming, are clearly visible on his translucent skin.

The placenta, working to nourish your little one by providing minerals, nutrients, vitamins, fats, proteins, and oxygen, is also growing and now weighs one to two pounds at birth. His vocal cords are also developing and taking its shape as well.

Wondering if your baby can breathe inside your womb? Yes! This week, your baby is now beginning to take his first breathes. The blood in the umbilical cord supplies oxygen to your little one while being surrounded by amniotic fluid. You can picture your baby breathing while under the water. The kidneys, one of the main organs of your baby, is already operational and is now capable of releasing urines, including the amniotic fluid that your baby swallows.

The pancreas, gall bladder, and thyroid have developed while bone marrow is now capable of producing white blood cells which will serve as his protection from infection.

External changes

Your baby’s head slows down growing in order for his body to catch up. On his tiny fingers, fingerprints can be seen and is now capable to make jerky movements, even putting his thumb into his mouth.

His facial features are already clearly showing, including his eyes, which can now move toward the center of his face instead of the side and hairs that make up the eyebrows are coming together now. Other notable developments this week are that the muscles and joints are flexing, and your baby is also starting to hiccup which can help to strengthen his diaphragm and practice his respiratory system for breathing.

Your Body Changes at 13 Weeks Pregnant

During this week, pregnancy symptoms are subsiding and you will be feeling good. However, some pregnant women may still experience these such as having nausea and fatigue during their 4 to 5 months pregnancy and it always varies. Others continue feeling the early pregnancy symptoms like bloating, constipation, headaches, breast tenderness, as well as smell and taste aversions throughout their pregnancy.

For pregnant women who are now feeling energetic and feeling less nauseous (which could completely disappear in the next two weeks), they are lucky to own their body again! It is due to the growing placenta that is now taking over the production of hormones in your body.

You will also notice that your breasts are already leaking colostrum, a fluid that is rich with nutrients which you will feed for your baby (your milk will begin to leak after). You will also notice that your waistline thickens; abdominal pains may start as well as pain around your ligaments. It is because your ligaments support your uterus that is being stretched and pulled.

Though it is completely normal, if you feel intense pain and that you notice blood leakage, talk to your health care provider regarding this. This may be a sign of a serious condition including possible miscarriage. You may be also experiencing frequent heartburn in chest and throat area, though your morning sickness eased.

You will also notice increase in vaginal discharge and it is called leukorrhea. It is a thin, milky, mild smelling vaginal discharge that you are seeing in your undies and normally increases throughout your pregnancy due to the high level of estrogen as well as blood flow on your pelvic area. The discharge serves as the protection of the birth canal against infection as well as keeps your vaginal area healthy from bacteria.

What to Think and Do while 13 Weeks Pregnant

You are about to go on your second trimester which would begin next week. While some of your early pregnancy symptoms subside and that you are feeling good and energetic, this is the perfect time to do some exercise to gain more energy.

Looking at yourself, you will notice that you have gained weight. That may be a good thing since it can reduced the chance of having stretch marks. Applying lotion with vitamin E and Alpha Acids may also help you avoid stretch marks. Make sure that you are into a healthy diet. Think for a good meal plan that you will follow throughout your pregnancy.

Starting from week 11 to 14, you can take ultrasound or screening test such as nuchal translucency for early detection of birth abnormalities. Talk to your health care provider regarding genetic or prenatal screening test and ask is if it is appropriate for you to take the said test (practitioners recommends this if there is a higher risk of birth abnormalities on the screening). There are also blood tests recommended to take by pregnant women, such as the sequential and serum integrated screening.

As your pregnancy progresses, all your need to think throughout is how to take care of yourself and your growing baby. Giving up your bad habits such as smoking, drinking or taking illegal drugs is a must. These things will affect the growth and development of your baby if you continue this. Make sure that you are taking medications prescribed by your health care provider at 13 weeks pregnant.


Editor in Babiology, mother of two, highly passionate about sharing the pregnancy care and post delivery care learning with the readers.

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