How Your Baby Grows During the Thirty-Ninth Week
The crown to rump length is still just a bit over 14 inches, but your baby's total length is probably closer to 20-21 inches now. He is about seven pounds and nearly ready for birth.
As he nears full term, the vernix that covered and protected his skin is being reabsorbed. The presence or absence of vernix is one of the signs of fetal maturity although even full term infants can still have vernix in the folds of their skin. Some hospitals routinely bath the baby after birth to wash the vernix away, but many parents prefer to rub the vernix in as a natural way to moisturize the baby's skin.
The baby's intestines are filled meconium now, a green-black substance that makes up the first bowel movements. New parents can be surprised by the tar-like bowel movements, but they are normal and nothing to worry about unless the baby has a bowel movement in the womb. This is called "meconium staining" in the amniotic water, and can be a sign of the baby being under stress. When your water breaks, your care provider will check for the presence of meconium in the amniotic fluid.
What the Mother Feels During the Thirty-Ninth Week
Your cervix may be changing now, a process sometimes called "ripening" and some women, especially those who have given birth before, may lose their mucous plug. Weight gain for an expectant mother slows down now, and some mothers may find they even lose a little bit of weight the last week or so before labor begins.
Braxton Hicks contractions are stronger and more noticeable now. You may experience two or three in a row, but these warm-up contractions would usually slow down when you lie down or take a bath.
It is important to stay well hydrated during these last days as your amniotic fluid is replenished regularly. In fact, every three hours the amniotic fluid is completely replaced. It is normal to add a little "water weight" or experience some swelling as well, because this is your body's natural defense against the fluids lost during birth.
Resources:
The Pregnancy Book: Month-by-Month by Dr. Sears
Your Pregnancy Week by Week by Lesley Regan
