Post-term Pregnancy

Where a pregnancy is longer than 294 days, or 42 weeks, it is described as a post-term pregnancy. It may also be described as a post-dates or prolonged pregnancy.

Dating a pregnancy is not an exact science.  A due date (which is the beginning of the 40^th week of pregnancy) is calculated from the first day of a pregnant woman’s last menstrual period or from the information provided on an ultrasound scan in early pregnancy. While these methods are both still estimates, the most reliable assessment of the estimated due date is by an early ultrasound performed in the first trimester – between 7-14 weeks.

Generally, being born after 42 weeks does not harm a baby. However, a small percentage of babies who have not been born by 42 weeks die before being born. The small percentage is significantly higher than the chance of a baby dying when born before 42 weeks.

There are risks to both the pregnant woman and her baby when the pregnancy continues beyond 42 weeks.

The risks to the pregnant woman include injury to the perineum and increased chance of an instrumental delivery or caesarean section delivery.

The risks to the baby include:

• suffering from fetal distress;
• aspirating or breathing in meconium which is the first bowel movement a baby has;
• shoulder dystocia;
• low blood sugar following delivery;
• difficulty breathing;
• seizures;
• suffering a brain injury.

The dating of a pregnancy is important as it helps avoid the complications from unknowingly going beyond 42 weeks. An early pregnancy ultrasound scan can help identify a due date where a pregnant woman has an irregular menstrual cycle or has bleeding in early pregnancy which makes timing of the last menstrual period unclear. A post-dates pregnancy is less common where a pregnant woman has an ultrasound in the first 12 weeks of pregnancy.

Membrane sweeping, where a midwife or obstetrician sweeps the inside of the cervix, can be done on or around the due date and this may encourage a pregnant woman to go into labour and so not go beyond 42 weeks. A sweep is not suitable for every pregnancy, but is generally considered to be safe for the pregnant woman and the baby and is also not too uncomfortable.

A pregnant woman may be offered induction of labour following 40 or 41 weeks of pregnancy. This can be done using medication placed close to the cervix in the form of a gel or pessary, or can be done by giving medication through a line into a vein.

Beyond 40 weeks, a pregnant woman should be closely monitored. Monitoring cannot necessarily prevent complications including a brain injury but there may be signs which indicate that expediting delivery would be beneficial to the pregnant woman and her baby.

If you delivered your baby post-term and your baby has a brain injury and you have concerns about how you were cared for in your pregnancy or delivery then please contact us – we would like to help.  We have a team of experienced lawyers and medical specialists who can review the medical care you received and help answer your questions. We will provide you with the information and advice you need to make informed decisions about your child’s future and ensure your child’s rights are protected. Rest assured – the consultation is confidential and free of charge.