Postmaturity is the condition of a baby that has not yet been born after 42 weeks ofgestation, two weeks beyond the normal 40.[1]Post-term, postmaturity, prolonged pregnancy, and post-dates pregnancy all refer topostmature birth. Post-mature births can carry risks for both the mother and the infant, including fetal malnutrition. After the 42nd week of gestation, theplacenta, which supplies the baby with nutrients and oxygen from the mother, starts aging and will eventually fail. If the fetus passesfecal matter, which is not typical until after birth, and the child breathes it in, then the baby could become sick with pneumonia. Postterm pregnancy may be a reason to induce labor.CausesThe causes of post-term births are unknown, but post-mature births are more likely when the mother has experienced a previous post-mature birth. Due dates are easily miscalculated when the mother is unsure of her last menstrual period. When there is a miscalculation, the baby could be delivered before or after the expected due date.[3]Post-mature births can also be attributed to irregular menstrual cycles. When the menstrual period is irregular it is very difficult to judge how and when the ovaries would be available for fertilization and subsequently result in pregnancy. Some post-mature pregnancies are because the mother is not certain of her last period, so in reality the baby is not technically post-mature.[2]However in most first world countries where gestation is measured by ultrasound scan technology, this is less likely.

Complications[edit]Fetal and Neonatal Risks[edit] Reducedplacental perfusionOnce a pregnancy has surpassed the 40 week gestation period, doctors closely monitor the mother for signs of placental deterioration. Towards the end of pregnancycalciumis deposited on the walls of blood vessels and proteins are deposited on the surface of theplacenta, which changes the placenta. This limits the blood flow through the placenta and ultimately leads toplacental insufficiencyand the baby is no longer properly nourished. Induced labor is strongly encouraged if this happens[citation needed]. Oligohydramnios Meconium aspiration

Maternal Risks[edit] Large for gestational age: Increased incidence offorcepsassisted,vacuum assistedorcesareanbirthPost-term babies may be larger than an average baby, thus increasing the length of labor. The labor is increased because the baby's head is too big to pass through the mother's pelvis. This is calledcephalopelvic disproportion.Caesarean sectionsare encouraged if this happens.[5]When post-mature babies are larger than average, forceps orvacuum deliverymay be used to resolve the difficulties at the delivery time. Difficulty in delivering the shoulders, shoulder dystocia, becomes an increased risk.[6] Increasedpsychological stress Probablelabour inductionMethods of monitoring post-mature babies[edit]Once a baby is diagnosed post-mature, the mother should be offered additional monitoring as this can provide valuable clues that the baby's health is being maintained.Fetal movement recording[edit]Regular movements of the baby is the best sign indicating that it is still in good health. The mother should keep a "kick-chart" to record the movements of her baby. Less than 10 movements in 2 hours is not a good sign and a doctor should be contacted. If there is a reduction in the number of movements it could indicate placental deterioration.Electronic fetal monitoring[edit]Electronic fetal monitoring uses a cardiotocograph to check the baby's heartbeat and is typically monitored over a 30-minute period. If the heartbeat proves to be normal the doctor will not usually suggest induced labor.Ultrasound scan[edit]Anultrasound scanevaluates the amount of amniotic fluid around the baby. If the placenta is deteriorating, then the amount of fluid will be low and induced labor is highly recommended. However, ultra sounds are not always accurate since they also monitor the fetus's development and if the fetus is smaller than normal the doctors guess at the age can be quite off. The actual placenta won't start to deteriorate until about 48 weeks[citation needed]. The reason why doctors favour induction by 42 weeks is because of the risks that are present.Biophysical profile[edit]A biophysical profile checks for the baby's heart rate, muscle tone, movement, breathing, and the amount of amniotic fluid surrounding the baby.Doppler flow study[edit]Doppler flow study is a type of ultrasound that measures the amount of blood flowing in and out of the placenta.[6]Expectant Management[edit]A woman who has reached 42 weeks of pregnancy is likely to be offered induction of labour. Alternatively, she can choose expectant management, that is, she waits for the onset of labour naturally. Women opting for expectant management, may also choose to carry on with additional monitoring of their baby, with regular CTG, ultrasound and biophysical profile. There is anecdotal evidence online of "10 month mamas" and women choosing to wait to 43 weeks and 44 weeks of pregnancy.[7]Risks of expectant management vary between studies.[8]Inducing labor[edit]Main article:Labor inductionInducing labor is artificially starting the labor process by using medication and other techniques. Labor is usually only induced if there is potential harm on the mother or child.[9]There are several reasons for labor induction; the mother's water breaks and contractions have not started, the child is post-mature, the mother has diabetes or high blood pressure, or there is not enough amniotic fluid around the baby.[10]Labor induction is not always the best choice because it has its own risks. Sometimes mothers will request to be induced for reasons that are not medical. This is called an elective induction. Doctors try to avoid inducing labor unless it is completely necessary.[9]Procedure[edit]There are four common methods of starting contractions. The four most common are stripping the membranes, breaking the mother's water, giving the hormoneprostaglandin, and giving the synthetic hormonepitocin. Stripping the membranes doesn't work for all women, but can for most[citation needed]. A doctor inserts a finger into the mother's cervix and moves it around to separate the membrane connecting the amniotic sac, which houses the baby, from the walls of the uterus. Once this membrane is stripped the hormone prostaglandin is naturally released into the mother's body and starts the contractions.[9]Most of the time doing this only once will not immediately start labor. It may have to be done several times before the stimulant hormone is released and contractions start.[11]The next method is breaking the mother's water, which is also referred to as an amniotomy. The doctor uses a plastic hook to break the membrane and rupture the amniotic sac. Within few hours labor usually begins. Giving the hormone prostagladin ripens the cervix, meaning the cervix softens, thins out, or dilates. The drug Cervidil is administered by mouth in tablet form or in gel form as an insert. This is most often done in the hospital overnight. The hormone oxytocin is usually given in the synthetic form of Pitocin. It is administered through an IV throughout the labor process. This hormone stimulates contractions. Pitocin is also used to "restart" labor when it's lagging.POSTTERM PREGNANCY CAUSESIn most cases, the cause of postterm pregnancy is unknown. There are some factors that place a woman at increased risk. The incidence is higher in first pregnancies and in women who have had a previous postterm pregnancy. Genetic factors may also play a role. One study showed an increased risk of postterm pregnancy in women who were, themselves, born postterm.However, variations in when a woman ovulates can lead to errors in calculating the true duration of pregnancy and lead to over- and underestimations of when the baby is due. An ultrasound examination performed in the first half of pregnancy is the most reliable method of calculating the date the baby is due, especially in women with long or irregular menstrual cycles.POSTTERM PREGNANCY TREATMENTAntenatal fetal monitoringIn most cases, a healthcare provider will recommend tests on the fetus if the pregnancy extends beyond the due date. These tests give information about the health of the fetus and about the risks or benefits of allowing the pregnancy to continue.The American College of Obstetricians and Gynecologists has stated that it is only necessary to start antenatal fetal monitoring after 42 weeks (294 days) of gestation, although many obstetric care providers will start fetal testing at 41 weeks. Many experts recommend twice weekly testing, including a measurement of amniotic fluid volume. Testing may include observing the fetus' heart rate using a fetal monitor (called a nonstress test) or observing the baby's activity with ultrasound (called a biophysical profile).Nonstress testingNonstress testing is done by monitoring the baby's heart rate with a small device that is placed on the mother's abdomen. The device uses sound waves (ultrasound) to measure changes in the baby's heart rate over time, usually over a period of 20 to 30 minutes. Normally, the baby's baseline heart rate should be between 110 and 160 beats per minute and should increase above its baseline by at least 15 beats per minute for 15 seconds several times during the test.The test is considered reassuring (called "reactive") if two or more fetal heart rate increases (called accelerations) are seen within a 20 minute period. Further testing may be needed if these increases are not observed after monitoring for 40 minutes.Biophysical profileA biophysical profile (BPP) score is calculated to assess the fetus' health. It consists of five components, nonstress testing and ultrasound measurement of four fetal parameters: fetal body movements, breathing movements, fetal tone (flexion and extension of an arm, leg, or the spine), and amniotic fluid volume. Each component is scored individually, 2 points if normal and 0 points if not normal. The maximum possible score is 10.Amniotic fluid volume is an important variable in the BPP because a low volume (called oligohydramnios) may be a sign of changes in the feto-uteroplacental circulation. Amniotic fluid level can become reduced within a short time period, even a few days.Contraction stress testA contraction stress test (CST) can also be done to assess fetal health. It involves giving an intravenous medication (oxytocin) to the mother to induce uterine contractions. The fetus' heart rate is monitored in response to the contractions. A fetus whose heart rate slows down during a CST may require an emergency cesarean delivery