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).
Some women feel more confident when they understand the next step to be taken if this step does not work. Often, caregivers are able to explain an expected course and next steps. Unfortunately, it can be difficult to predict how a baby will respond to induction attempts with a failing placenta. This can make it more difficult for a caregiver to formulate a plan at the begining of an induction, which might make some women more anxious. For example, if an induction is begun the baby may tolerate the induction well, have a non-reassuring heart rate right away, or may tolerate an induction up to a point. When a baby tolerates the induction "to a point," your caregiver will need time to assess if the amount of medication used is able to progress labor before being able to give you information on the safest ways to proceed. It is this uncertaintly that causes some women excessive anxiety and stress during labor.
True post-maturity is rare, consider 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. Ask your caregiver questions about things you do not understand.
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 is able to help 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.
If you have an induction your baby tolerates "to a point", make sure your caregiver knows what information you need to feel confident in decision making. For some women this will be only that the baby is tolerating the current level of medication well. Other women will want to know how often assessments will need to be made. Some women will want to know if or when medication dosages will be increased. If you find you have a high need for information, be sure to find out what information you can receive from the nurse and what questions to make sure are asked when your caregiver is present.
References: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.