Postmaturity
When Baby Has Not Arrived 2 Weeks After Due Date

Postmaturity

Contents

• What Does Postmaturity Mean?
• How Is It Diagnosed?
• What Are The Dangers Of Postmaturity?
• How Is It Managed?
• Postmaturity Signs In A Baby

Postmaturity means the prolongation of pregnancy beyond its normal duration. It is important to recognize a case of postmaturity because research shows that the risk of intrauterine fetal death increases, particularly in pregnancies continuing more than 2 weeks beyond term (term is considered 40 weeks after conception). However, there is no agreement on the normal limits of duration of pregnancy. The difficulty in making any definition is that the precise date of conception in any particular pregnancy is unknown, and even with regular menstrual cycles of normal length the date of ovulation is only approximately known. In women with irregular or prolonged cycles calculations based on the date of the last menstrual period are bound to be inaccurate. Apart from the uncertainty about the date of ovulation, it is highly unlikely that all fetuses will mature in precisely the same number of days.

How Is It Diagnosed?

General statistics show that 10 percent of all deliveries occur at least 2 weeks after the expected pregnancy due date. But not all of these cases can be diagnosed as postmaturity. In cases in which the date of the last menstrual period is absolutely certain, and in which the previous menstrual cycles were of normal length, the diagnosis of maturity can reasonably be based on this. If the menstrual history is uncertain an attempt can be made to assess maturity by looking of the neonatal records to discover whether the size of the uterus was determined by bimanual examination at an early prenatal visit. Between the 8th and the 14th weeks an accurate assessment of the uterine size can generally be made, this will help determine the gestation age. Pregnancy ultrasound measurements of the crown-rump length of the fetus up to about the 14th week and of the diameter of the fetal head up to about the 28th week, will also help. The date at which the mother first felt fetal movements may be of interest, but as this can range from 16 to 22 weeks, it isn’t enough evidence on which to base any important decision.

What Are The Dangers Of Postmaturity?

The delayed onset of labor can cause:

• Placenta problems: mainly where the placenta becomes inadequate for a large fetus that is still growing - this is known as placental insufficiency.
• Childbirth problems because of the increased size of the fetus. Also, a uterus that is slow to begin labor may also prove to be inefficient during labor.
• Death of the baby from hypoxia (lack of oxygen) before the onset of labor, although this is rare.
• The risk of fetal distress during labor is greater in postmature births than in normal births. This is partly caused by a more difficult labor due to the larger size of the fetus. It may also be due to a more frequent occurrence of oligohydramnios.
• Postmature babies are at risk of meconium aspiration (where the baby breathes in fluid containing their first stool).

How Is It Managed?

Postmaturity is often a cause of worry, and sometimes an inconvenience to the mother. Pressure is often put upon the obstetrician to induce labor. While labor induction is often justifiable in cases in which the menstrual history is certain, in other cases there is a risk that the fetus may, after induction, prove to be premature rather than postmature. The clinical evidence must be carefully reviewed before deciding to induce labor. Uncertainty over gestational age is eliminated by early ultrasound dating and is a very strong argument in favor of routine scanning of all pregnant women in the second trimester.

Since many women and their partners tend to worry when the date given to them as the expected date of delivery passes, it is best that every mother should be told that the calculated date is only an approximation, and that normal labor may start up to 2 weeks later.

Each case of suspected postmaturity should be dealt with according to its special circumstances. There is no justification for making a rule that all cases must be induced at some stated week of pregnancy; the risks of indiscriminate induction might well exceed those of postmaturity. There will be more anxiety in the case of older mothers or those suffering hypertension during pregnancy. Induction might well be recommended if the fetus is evidently large. There can be little justification for induction until the woman is at least 2 weeks overdue except in cases with hypertension or some other reason to suspect placental insufficiency.

Labor may be induced in cases of postmaturity by insertion of vaginal prostaglandin pessaries. If labor does not quickly follow, amniotomy (also known as artificial rupture of membranes) is performed. When the fetal head is well down in the pelvic cavity and the cervix is soft and taken up, labor follows induction without delay. Very careful monitoring of the progression of the labor and of the condition of the fetus are required. Particular attention is paid to whether or not amniotic fluid is draining. If there is evidence of fetal hypoxia during the first stage of labor, preferably confirmed by examination of a sample of fetal blood obtained by scalp puncture, cesarean section may be necessary. In the second stage of labor (see stages of labor), clinical signs of fetal distress will result in the need for a forceps delivery without delay.

Postmaturity Signs In A Baby

When a baby is born the following are the most common signs of postmaturity:

• Overgrown nails.
• Dry pealing skin.
• Visible wrinkles or creases on the soles of the feet and palms of the hands.
• Lots of hair on the head.
• Green, yellow or brown skin color from meconium staining (the baby’s first stool passes into the amniotic fluid).

For other topics, see the following:

• Kidney infection during pregnancy: Signs, diagnosis and treatment.
• Fever in pregnancy: What can cause fevers in pregnant women?
• Digestive problems in pregnancy: Common tummy disorders.

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