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.
- 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 mold her tiny head into a cone shape; 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 moms 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: If you're delivering vaginally, you'll push your baby into the vaginal canal and out of your body.
- 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.
Early or late?
It's important to realize that you may normally deliver 2 weeks earlier or later than your due date, but the odds are slim that you'll give birth exactly on schedule. Only 5% of babies are born on their due dates.
About 10 percent of pregnancies result in a "post-term pregnancy" where the baby is still not born 2 weeks after the due date. This may be of concern because the amniotic fluid level usually drops after the 41st week, increasing the risk that the umbilical cord could become compressed, depriving your baby of oxygen. Post-term pregnancies also increase the risk that your baby will pass meconium into the amniotic fluid, where it could get into her lungs.
Inducing labor
If you have gone 2 weeks past your due date, your doctor may want to perform fetal testing to gauge whether labor will begin spontaneously. If necessary, your doctor may choose to induce labor by artificially puncturing the amniotic sac with a sterile tool. The painless procedure releases the amniotic fluid out of the vagina. Puncturing the sac boosts the level of a hormone that helps speed up contractions.
Doctors also can induce labor by administering synthetic hormones that help to strengthen contractions. If your pregnancy is high risk or if there are any other potential complications, you may require a cesarean section delivery.
