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All about going overdue

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Here’s a word of advice for when you’re first pregnant and letting friends and family in on your good news: tell them your due date is two weeks after the date given to you by your midwife or doctor. This will save you a lot of tiresome phone calls if you go over your due date!

Though pregnancy technically lasts 40 weeks, babies can be born quite safely anywhere between 37and 42 weeks. Remember, the due date given to you is an estimate only and that day may come and go with no signs of labour. And, as my grandmother used to say, “Babies are like cucumbers – they don’t all ripen at once!”

The majority of babies are, however, born before 42 weeks, with only a small percentage of babies staying in beyond this. Women having their first baby are more likely to go overdue and women who have had a previous baby come late are likely to go past their due date again.

A best guess
At your first appointment, your estimated date of delivery will be calculated using the date of your last menstrual period. This way of calculating your due date has to take into account the length of your menstrual cycle and, as a result, can often be inaccurate. The date will be confirmed when you have your first ultrasound.

Early ultrasounds at around eight to 12 weeks are more accurate for estimating the due date than ultrasounds performed later. In fact, the later in the pregnancy the ultrasound is done, the more inaccurate it can be for estimating the due date. If the ultrasound is different by more than a week to the due date calculated from your period, then the ultrasound date will be used as your ‘official’ date – but, of course, it’s not an exact science and the day your baby is born can be two weeks either side.

42 weeks later…
Generally, if your baby hasn’t come before 42 completed weeks of pregnancy, your doctor or midwife will discuss induction of labour with you. After 42 weeks, the placenta may not function to nourish the baby properly, so it’s advised labour be brought on to ensure that the child is looked after. In my experience, most hospitals advise induction at around 40 weeks plus 10 days.

The concern for bub increases the longer the pregnancy goes beyond 42 weeks, so if you’re very committed to avoiding an induction, you’ll need to monitor the baby regularly after 41 weeks to ensure she remains in good health. There’s a popularly held belief that overdue babies are always large, but this isn’t the case and an induction for the size of bub is not supported by research.

You may also need to be induced early. If you have a health problem that may affect the baby, a decision will be made as to whether she is better off being born or staying inside. A few conditions, such as cholestasis (a build-up of bile acids in the blood), intrauterine growth retardation (when the baby is malnourished in the uterus) and gestational diabetes, may require the baby to be born sooner rather than later, so going overdue would not be advised.

There is also some research that says mums over 40 years of age shouldn’t go overdue, as there is an increased number of problems with their babies. If you’re in this age bracket, discuss this with your midwife or doctor.

Watchful eyes
If you do go overdue, you may be asked to go to the hospital a few times a week for cardiotocograph (CTG) monitoring of the baby. Two straps will be placed around your belly, one which records the baby’s heartbeat and the other which detects any contractions. You may also be asked to have an ultrasound to make sure your baby has a good amount of amniotic fluid around her.

If you do need to be medically induced, there are three key methods used to get things moving: having prostaglandin gel inserted into your vagina and/or having your waters broken by your caregiver and/or having a drip of the synthetic hormone Syntocinon administered.

If you go overdue, though, don’t stress – it’s quite normal. If you’re worried, discuss your concerns with your doctor or midwife. Find a new project to distract you from the waiting and focus on that. Also, many women find that once an induction is booked, they go into labour before the induction day!

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