What is a post-term pregnancy?Any pregnancy that goes beyond 42 weeks is considered post-term. A large number of women normally deliver between 37 and 42 weeks of gestation. Statistically, around 7.4 percent of all babies are born at 42 weeks or later.
What are the causes?It is not known as healthcare providers can’t point out why some women carry a pregnancy longer than others. In some cases, it may be due to a miscalculation of pregnancy conception dates, which leads to a miscalculation of your due date. A woman is more likely to have a post-term pregnancy if:
- They are pregnant with their first baby
- Had past pregnancies that went past 42 weeks
- Are overweight
- Are having a boy
Why is This a Concern?
Longer labours and operative delivery are mostly associated with post-term pregnancy, with mothers at an increased risk for vaginal birth trauma due to a larger baby. This makes cesarean delivery twice as likely to be performed in a post-term pregnancy.
There are risks for the foetus and newborn as well. Toward the end of gestation, the placenta – which is the sole supplier of nutrients and oxygen to the foetus – starts to age and may not function as efficiently. There may also be a decrease in amniotic fluid volume, which may result in the foetus losing weight.
During labour and birth, the risks can increase for a foetus with poor oxygen supply, resulting in birth injury especially if the baby is large. Babies born after 42 weeks may be at risk for meconium aspiration and hypoglycemia (low blood sugar) – due to the baby having too little glucose-producing stores.
How is post-term pregnancy diagnosed?
Correctly dating a pregnancy through antenatal check-ups, is important when diagnosing and managing post-term pregnancy. The following can help confirm pregnancy dates:
- The size of the uterus at various points in early pregnancy,
- the dates the foetal heartbeat was first heard, and a
- when a mother first feels foetal movement
Ultrasound is often used in early pregnancy to assess foetal development. In a post-term pregnancy, testing may be done to check the well-being of the foetus and to identify if there are any problems.
Management of post-term pregnancy
The management of post-term pregnancy goal is to prevent complications and deliver a healthy baby. Some of the ways to detect potential problems include the following:
- Foetal movement counting – keeping track of foetal kicks and movements.
- Nonstress testing – watching the foetal heart rate for increases with foetal movements.
- Biophysical profile – Combining the nonstress test with an ultrasound to evaluate foetal well-being.
- Ultrasound – Ultrasounds are used to follow foetal growth. This is done through a diagnostic imaging technique using high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
If tests determine that it is no longer healthy for the foetus to stay in the mother’s uterus, labour may be induced to deliver the baby.
When labour does not progress or the foetus is under distress, a cesarean delivery may be needed. Very large babies may have difficulty at delivery, and forceps or vacuum-assisted delivery may be needed.