Week 17-20

Week 17

The baby: the baby is now 4. 4 - 4. 8 inches long and weighs approximately 3. 5 ounces. Adipose tissue, or fat deposits, begins to grow on him. This tissue serves to help the baby in heat production and increases his metabolism. The circulatory and urinary systems are now fully functioning and the respiratory system is exhaling amniotic fluid that has built up in the lungs.

The mother: By this week the mother is most definitely showing as her uterus has grown to just under her belly button. In terms of weight gain, five to ten pounds should be expected by this point.

Week 18

The baby: the baby is now approximately 5 to 5. 6 inches long and 5. 25 ounces in weight. The baby's rapid growth begins to slow slightly during this week, but his movements are getting greater and more complex in nature. He can now stretch, kick, yawn and make different facial expressions. An ultrasound during this week is typical and can be used to detect heart abnormalities and other defects such as Down Syndrome. Furthermore, the baby is now developing taste buds and the eyes are developing and becoming sensitive to light.

The mother: At this stage of pregnancy the mother should see a weight gain of between ten and thirteen pounds. Remember this is an average and her weight could vary widely from these numbers. This is normal and unless her weight gain is drastically under or over this average there is no cause for concern. If her weight is an issue, she should contact her physician and ask to have a meeting arranged with a nutritionist. Excessive weight gain during pregnancy can make delivery more difficult. With this weight gain back pain may become a problem as the mother's growing uterus shifts her center of gravity over her legs. She should be able to feel her uterus directly under her belly button now.

Week 19

The baby: the baby is now between 5. 2 and 6 inches in length and weighs approximately 7 ounces. The baby's regular growth continues into this week.

The mother: By this week the mother should have gained between 8 and 14 pounds. Dizziness caused by hypertension is very common during the middle of the second trimester and she may already be experiencing it. The weight gain may also cause back and leg pain, constipation, and swollen ankles. The mother may also begin to notice small, temporary red marks on her body - typically they are found on the face and back. These marks, or spider nevi, are caused by dilated blood vessels.

Week 20

The baby: the baby is now between 5. 6 and 6. 4 inches in length and weighs approximately 9 ounces. His skin begins rapid growth from its two layers - the epidermis (outer-layer) and the dermis (deeper, inner-layer). The skin also begins to secrete vernix which is a creamy white coating that protects the growing skin from amniotic fluid. Hair begins to appear which will be the baby's permanent hair, different from the lanugo hair. An ultrasound at this point will help to establish or confirm the mother's due date and will also be able to detect some fetal problems.

The mother: This is now the midpoint of the mother's pregnancy. Congratulations! Her uterus should now be nearly level with her belly button and her growth should become quite regular compared to the sporadic growth experienced over the last 20 weeks. It is not uncommon for the doctor to begin measuring the mother's weekly uterine growth from this point on. It can be expected that her uterus will grow approximately 0. 4 inches per week from now until near the end of pregnancy. The mother's thyroid gland is becoming increasingly active and this may cause the mother to perspire more. As well, the mother's breathing will become deeper as her body's demand for oxygen increases. Of final note, the mother's urinary tract muscles are likely relaxing near this stage of pregnancy, thus making the chances of bladder infections much greater.

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