Shoulder dystocia – Difficulty in delivering the shoulders due to increased body size. Increased forceps-assisted or vacuum-assisted birth – When postterm babies are larger than average, forceps or vacuum delivery may be used to resolve the difficulties at the delivery time, such as shoulder dystocia. Complications include lacerations, skin markings, external eye trauma, intracranial injury, facial nerve injury, skull fracture, and rarely death. Mother
Increased labor induction – Induction may be needed if labor progression is abnormal. Oxytocin, a medication used in induction, may have side effects such as low blood pressure. Increased forceps assisted or vacuum assisted birth – operative vaginal deliveries increase maternal risks of genital trauma. Increased Caesarean birth – Postterm babies may be larger than an average baby, thus increasing the length of labor. The labor is increased because the babys head is too big to pass through the mothers pelvis. This is called cephalopelvic disproportion. Caesarean sections are encouraged if this happens. Complications include bleeding, infection, abnormal wound healing, abnormal placenta in future pregnancies, and rarely death.A 2019 randomized control trial of induced labor at 42 or 43 weeks was terminated early due to statistical evidence of "significantly increased risk for women induced at the start of week 43". The study implies clinical guidelines for induction of labor no later than at 41 gestational weeks. Causes
The causes of post-term births are unknown, but postmature births are more likely when the mother has experienced a previous postmature 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. Postmature births can also be attributed to irregular menstrual cycles. When the menstrual period is irregular it is difficult to judge the moment of ovulation and subsequent fertilization and pregnancy. Some postmature pregnancies may not be postmature in reality due to the uncertainty of mothers last menstrual period. However, in most countries where gestation is measured by ultrasound scan technology, this is less likely. Monitoring
Once a pregnancy is diagnosed postterm, usually at or greater than 42 weeks of gestational age, the mother should be offered additional monitoring as this can provide valuable clues that the fetal health is being maintained. Fetal movement recording
Regular movements of the fetus 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 fetus. If there is a reduction in the number of movements it could indicate placental deterioration. Doppler fetal monitor
Doppler fetal monitor is a hand-held device that is routinely used in prenatal care. When it is used correctly, it can quickly measure the fetal heart rate. The baseline of fetal heart rate is typically between 110 and 160 beats per minute. Doppler flow study
Doppler flow study is a type of ultrasound that measures the amount of blood flowing in and out of the placenta. The ultrasound machine can also detect the direction of blood flow and display it in red or blue.