You have made it through the most challenging one-third of your journey to motherhood. The first trimester is almost over with the risk of miscarriage dropping significantly and your baby having grown all the principle organs and body parts. Check out the fetal growth this week as well as the warning signs that call for medical attention.
The intestines continue settling in their new and permanent place in your baby’s abdomen with the construction of the vocal cord beginning at the same time . The major organs start working around the same time with the pancreas producing insulin, the liver secreting bile and the kidneys forming urine for carrying away any waste materials. At this stage, the urine is passed in the amniotic fluid surrounding the baby .
The testes or ovaries are already done growing depending on the sex of your baby . A female fetus will now have around two million eggs in the ovaries, which will go down to one million at the time of birth .
Bony tissues start to grow in the tiny arms and legs around this time , while sucking muscles begin developing in the cheeks. Your baby has already started practicing the reflexes he will later need while nursing .
This is the week when your baby starts developing unique fingerprints at his fingertips . Since he has already started moving those tiny arms and legs, your baby may even be able to put his thumb into the tiny mouth by this week .
Your baby is looking more and more like a tiny human with the head and body gradually coming into proportions. The head constitutes only one-third of the total body now . However, there is still no fat , which makes him look quite thin and pinkish. This is also the week when the external genital organs start to develop .
Your tiny miracle is now 2.9 inches (7.4 cm) long, about the size of peach, weighing around 0.81 oz (22.9 gm) .
The morning sickness that has kept you down for the last 3-4 months starts to retreat by the 13th week along with many of the other exhausting symptoms. You may still need to use the bathroom oftener than usual, but the frequency will soon start going down due to the uterus moving away from the pelvic bones and bladder .
You may also notice your ribcage expanding a little to accommodate the growing uterus while your bellybutton may already stat to stick out as well . It is normal to get a bit clumsy at this stage due to the relaxin hormone released by your body that relaxes the joints, muscles and ligaments .
The uterus is gradually moving upwards, causing a small bump to develop in your belly . But, it is still too early for anyone to notice it but yourself, especially if it is your first pregnancy. Subsequent pregnancies or carrying twins may make you show earlier.
The still see-through skin  makes it possible to view the growing veins, blood vessels and internal organs on an ultrasound image. Although the sex organs are almost done developing, it is often too difficult to determine the gender of the baby with ultrasound during the 13th week .
Your baby’s heartbeat may sound quite alarming on a Doppler device as it is currently twice as fast as your own. But it will gradually slow down to normal before birth . An ultrasound will also show your baby making jerky movements, kicking his legs and flexing those tiny arms, but it is still too early for you to feel these movements .
On the positive side, your early pregnancy symptoms of nausea, vomiting, fatigue, mood swings, food aversions and increased sense of smell are finally starting to go away as you are entering your second trimester, often claimed to be the least symptomatic of the three . Another great thing about this week – your energy levels start to go back up  as you feel less and less drowsy with each passing day. However, there is nothing to worry about if you continue to feel weak, tired and nauseated as every pregnancy is unique with its own symptoms and complaints. Here are the common signs of the 13th week:
Published on June 17th 2014 by Pregmed Editorial Team.
Article was last reviewed on 13th August 2014.