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Home   3rd Trimester   39 Weeks Pregnant

You’re 39 Weeks Pregnant!

Your baby is the size of a watermelon.1

Developments in Baby:

Ready for the World

Your “little one”—perhaps the idea of delivery makes Baby seem quite large—can be anywhere from 6 to 9 pounds at this point but is averaging out at 7 to 7.5 pounds (3.25 to 3.4 kilograms) and measuring 21.5 inches (54.6 centimeters).1,2,3 Baby’s abdominal circumference, consisting of 15% of his body fat, has surpassed that of his head as Baby continues to pack on the fat. Baby has enough fat beneath the skin, around muscles, and around some of the abdominal organs to regulate his body temperature and create that cute, chubby look.2 Baby also continues to shed the vernix caseosa and the lanugo; his skin will transform from a pinkish color to almost white.  This is actually true of babies with darker skin as well.2 All of this development qualifies Baby as clinically mature and ready for the world. As long as baby remains in your belly, however, Baby will continue to become smarter as his brain develops.

Gravity at Work

Just as your body is making preparations for the big day, Baby is doing everything necessary for a smooth delivery. Her head remains the largest part of her body, and, chances are, it is resting right against your cervix. The pressure on the cervix will help thin the tissues, creating an opening in the birth canal. Gravity is at work, pulling her further and further down into your pelvic girdle and compressing her head to a certain degree.

Active Antibodies

The placenta, which has sustained Baby up to this point, is becoming less efficient at transferring nutrients, thus your antibodies are crossing the placental barrier and are able to give her that extra boost that Baby’s immune system will need as she passes through the birth canal. During the first six months of life, these very same antibodies will help her immune system fight off infections. Should you choose to breastfeed, Baby will also receive vital nutrients and antibodies from you after birth. The umbilical cord, is about 2 centimeters thick and the length of your baby, still supplies her with nutrients as she gains weight. It is common for the umbilical cord to be knotted or wrapped around Baby until birth.

Developments in Mother:

Last Leg of the Journey

The same old symptoms are present and will be until Baby is finally in the world. Your uterus continues to expand, taking up all of the space in your pelvis and a great deal of room in your abdomen, pressing against the ribcage. The taut skin over your belly may become itchy as it gets increasingly tight. Your circulation is working harder than ever before, possibly leaving you with a flushed appearance. Weight gain is beginning to plateau, and some women even lose weight in the very end. Discomfort is common at this point. Impatience, nervousness, and excitement may intensify.1 Don’t be in too much of a rush, however. Remember that Baby will take all the times she needs to ensure he is fully developed.

Softening Cervix

Your antenatal appointment will consist of an outer checkup- the doctor may feel your abdomen to observe the baby’s position and growth2—as well as an internal exam in which your practitioner will check for cervical softening, effacing (thinning), and dilating (opening). All of the pressure on your pelvic floor is ripening your cervix in preparation for Baby’s passage.

Is It Real?

Labor is just around the corner, but don’t be fooled by false labor contractions. It is common for contractions to become stronger than Braxton Hicks, but they may be weaker than the real deal. If they go away when you move or change positions, you can rest assured that they are false labor contractions.2 True labor will be identified by longer and stronger contractions that do not ease up with movement, amniotic fluid leaking or water breaking, and the bloody show, or viewing a dislodged mucus plug tinged with blood due to ruptured capillaries. Call your practitioner immediately if you feel that your water broke or you are leaking amniotic fluid.  Even if you are unsure, it’s always best to check.


It may be a great time to read up on the basics of newborn care.
Keep relaxing with any extra time that you have.

Week 39 Basics:


Continued symptoms
Expanding Uterus
Itchy belly
Reduced weight gain
Heightened feelings
Cervix ripening
Know the difference between false labor and true labor

7-7.5 lbs. (3.25-3.4 kilos), 21.5 in. (54.6 cm)
Fat continues to accumulate
Skin becomes whitish in color
Brain developing
Cranium pressure on pelvis preparing the cervix for delivery
Building immune system
Still receiving nourishment from the umbilical cord


1. Roney C.  The Baby Bump: 100s of Secrets to Surviving Those 9 Long Months.  San Francisco, CA: Chronicle Books; 2010

2. Murray LJ, ed.  Pregnancy: From Preconception to Birth.  New York, NY: DK Publishing; 2010

3. Murkoff H, Mazel S.  What to Expect When You’re Expecting.  4th ed.  New York, NY: Workman Publishing Company, Inc.; 2008


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