from The Merk Manual..."An uncommon syndrome of failing placental function and fetal jeopardy that occurs after 42 wk."
In plain English, this means your baby is not able to get what he needs because the placenta is not working right any more. Babies who are postmature are sick because they are no longer being properly nourished.
When born, a postmature baby will seem alert, but is very lean (the skin may be hanging on the body) because the baby was living off his own fat supplies for nourishment. Postmaturity has a range of symptoms including the loss of subcutaneious fat, dry cracked skin, meconium staining, birth asphyxia and respiratory distress.
Why is this a labor challenge?
Caregivers begin assessing the health status of a baby for postmaturity when they get close to being overdue. There are many ways to assess fetal well being, and there is some evidence this surveillance can detect when something is wrong. However, there is very little evidence that using these surveillance methods improves outcomes or reduces the risk for post-term (overdue) pregnancies.
If at anytime the results of a non-stress or stress test or a biophysical profile indicate that there is cause for concern, your caregiver will recommend immediate induction. If your body does not appear able to successfully survive labor, your caregiver may recommend a cesarean surgery.
According to the Merk Manual, babies who are post mature are at a higher risk of:
Asphyxia during labor (they cannot get oxygen because the placenta is not working properly)
Meconium aspiration syndrome (they may choke on their own first bowel movements because of a lessened amount of amniotic fluid and increased amount of bowel movements in utero)
Neonatal hypoglycemia (because their bodies do not have sufficient stores of fat to maintain blood glucose levels).
True post-maturity is rare, be sure to get a second opinion before deciding to induce labor.
Use the least restricting methods of induction first, using other methods if necessary.
Be sure to stay aware of the baby's health.
Things to discuss with your caregiver:
Be sure to keep yourself well hydrated. Studies have shown that drinking water increases the amount of amniotic fluid. If you are dehydrated at a prenatal appointment, the lower fluid volume may cause your caregiver to become concerned about postmaturitiy.
When you and your caregiver are confident your baby is postmature, you can discuss options for how to begin labor. Because postmature babies are at increased risk for asphyxia and meconium aspiration, you may have fewer options about how your caregiver helps you in labor. For example, it may be recommended you not use certain medications, or that you only have a "trial" of contractions to determine if your baby is handling them well before deciding to continue an induction.
Carlomagno G, Candussi G, Zavino S, Primerano MR. Postmaturity: how far is it a clinical entity in its own right? Clin Exp Obstet Gynecol. 1996;23(1):41-7.
Enkin, Keirse, Nilson, Crowther, Duley, Hodnett and Hofmeyr. A guide to effective care in pregnancy and childbirth Third Edition. 2000. Oxford: Oxford University Press.