Throughout your pregnancy your baby will grow and change from a single cell to a complex newborn, capable of independent life. Each week brings new and exciting developments. Week 17 occurs in the second trimester, near the middle of the pregnancy, making it a wonderful time to explore what your unborn baby now looks like.
Size
The average weight of an unborn baby at 17 weeks is 4.97 oz, according to Pregnancy.org. Your baby is also somewhere between 5 and 6 inches in length. That is roughly the size of a one week-old kitten.
Head
By week 17, your baby's head has rounded and become more recognizably human. The eyes remain sealed shut, but are now forward facing, the nose is formed and some of the ear structure is forming, allowing your baby to begin to hear. Your baby may also be opening and closing its mouth and making sucking movements.
Skeletal
So far the structure of your baby has been made of cartilage. At this time, the cartilage starts to remodel and become flexible bone. This also means that the joints become more mobile and your baby starts to flex them, moving more than ever before. The arms and legs of your baby have caught up to the head size, allowing for a more proportionate appearance.
Skin
The skin remains thin but now begins to develop a protective sealant known as vernix. Vernix is a white, waxy coating that helps protect your baby's skin. It will take several weeks, yet, before the vernix is fully formed. Your baby's fingers and toes are also forming little pads on the end that will develop into individual fingerprints.
Other Developments
In addition to the changes you can see, your baby is developing internally too. Meconium is collecting in your baby's intestines. This will become your baby's first bowel movement. If your baby is a boy, the prostate gland has just developed and if your baby is a girl, the precursors of eggs are developing inside her ovaries.
Caution
Remember that every pregnancy is unique. An ultrasound may find that your baby is slightly ahead of or behind these milestones. Consult your obstetrician if you have any concerns about how your pregnancy is going or how your baby is developing.
