Week 20
The fetus now weighs about 9 ounces (260 grams) and measures 5.5 to 6.3 inches (14 to 16cm) from crown to rump. The baby’s growth is taking up increasing room in the uterus. This continuing growth will put pressure on the mother’s lungs, stomach, bladder, and kidneys. Under the vernix caseosa (a protective, creamy coating), your baby’s skin is thickening and developing layers, including the dermis, epidermis, and subcutaneous layer. Hair and nail growth continues this week.

There are a few things that may happen this week. First, your belly button may “pop out”. This happens because your uterus is pressing up and outwards, and it will stay like that until your baby eventually drops into the pelvic area.

Your health care provider may recommend that you receive an ultrasound, a diagnostic test that uses sound waves to create an image. An ultrasound, usually performed around the twentieth week of pregnancy, can be used to determine the size and position of the fetus, as well as any structural abnormalities of bones and organs that are visible by this time. Depending on the position of the fetus, the sex can sometimes be determined. During an ultrasound, the umbilical cord, placenta, and amniotic fluid can also be examined. Talk to your health care provider about the risks and advantages of this test.