Week 40: Your pregnancy
Your baby's growth: You have a baby!
The average birth weight for babies born at 40 weeks is about 7 pounds 8 ounces, and the average length is about 21 inches.
There are a number of surprising physical characteristics you may notice upon your little one's arrival. You may not have realized the extent to which your hormones can affect your baby at this stage. Because of the presence of your hormones in your baby's system, your baby's genitals (scrotum in boys and labia in girls) may appear enlarged. Your baby boy or girl may secrete milk from the tiny nipples. This is another hormone-related occurrence that should disappear in a few days and is completely normal. Finally, hormones may cause some "infant acne" pimples on your baby's face. These too will disappear within a month or so of birth.
Other developments:
- Skin. Although many moms think of a baby's skin as "perfect," it can be very sensitive. When your baby is born it's normal for her to have skin discoloration; blotchy, dry skin; or even rashes.
- Head shape. Your baby's trip through the constricting birth canal will temporarily elongate her tiny head; this will round out within a few days of life.
- No tears. Babies are capable of crying at birth, but they are born with an underdeveloped tear duct system. You may notice that tears don't appear until 1 to 3 months of age.
- Umbilical cord. After the cord is cut, a remnant will remain attached to the baby's abdomen. It will drop off within the first month.
What's happening with you
By now you're anticipating the delivery of your baby. When you're ready to deliver, you'll experience the following three basic stages of labor:
First stage: Your uterus contracts at regular intervals, thinning and stretching your cervix. This stage lasts the longest because the cervix must widen from zero to 10 centimeters.
The average duration of first-stage labor in new women experiencing their first labors is about 12 hours. For moms who have experienced labor and delivery before, it may be half that long. However, first-stage labor can range from much shorter to much longer than 12 hours and still be considered normal.
- Second stage: This is the time your baby moves through the vaginal canal and out of your body, due to a combination of uterine contractions and your pushing efforts. It usually lasts an hour or two with the first birth, but can be much shorter with later ones.
- Third stage: The final stage of labor occurs when you deliver the placenta. After the baby has been delivered, the placenta separates from the uterine wall within about 10 minutes. Your doctor will massage your abdomen to help move the placenta along. Your doctor may need to reach inside and remove the placenta if it isn't expelled on its own.