When expectant mothers go beyond their expected date of delivery…

You have probably heard of a lady who has gone beyond their expected date of delivery (EDD). This is known as post tom pregnancy. “Post-term pregnancy is defined as a pregnancy that extends to 42 weeks and beyond,” says Aaron B Caughey, an associate professor in the department of Obstetrics and Gynaecology at the University of California in San Francisco.

Dr Mike Kagawa, an Obstetrician and Gynaecologist with Mulago Hospital, explains that a number of reasons could be behind this. But first it is important to have this at the back of one’s mind. “When we tell expectant mums when the baby will come, it is an estimate,” he says.

The commonest cause thus far is when the dates are wrong. Dr Kagawa explains that it’s important to be clear on the actual date of one’s last normal period. Normal period in this case is determined by consistency with the duration, timing, the presence or absence of menstrual pains or the things that usually happen when one is menstruating. This is what doctors aim at.

At times, mothers give a date without taking the above into account. In addition, some women are not clear on the date and simply pick a random date, the doctor notes. Caughey noted that this is even worse when it comes to women with irregular periods, or who have been on hormonal birth control like the pill, or who suffer first trimester bleeding.

Another cause of this variation is technology, more so the ultrasound. “The results depend on the individual, the machine used and the timing. When a scan is done too early or too late, it may not be accurate,” Dr Kagawa notes, adding, “An ultrasound done between 17-21 weeks usually gives an accurate delivery date. An allowance of plus or minus one week is given.”

But as fate would have it, some people genuinely go beyond their due date. “There are two categories of these,” he explains, “The first group do not start labour until induced.” This he says, can not easily be explained but once induced, the labour proceeds normally.

In the second group are those that have medical problems. “As far as we know, the baby decides when it’s ready to come out,” Dr Kagawa says. This is why a doctor may not want to induce labour sometimes.

However, sometimes the baby may delay because they have congenital they are born with anomalies, health complications especially those involving the brain. An example, he says, is a condition medically termed anencephaly, where the brain lacks its outer covering (or skull). “The pregnancy can even be overdue by two months.”

In Dr Caughey’s article, other factors like the baby being male, genetics, previous post-term pregnancy and the fact that one is giving birth for the first time (primiparity) also lead to post-term pregnancy. “All that said, we do not want babies going beyond their due-date,” Kagawa says, explaining that as the baby grows, so does the placenta because it is the route by which the baby gets nutrients. At 40 weeks, this growth is no longer proportional. The baby keeps growing, but the placenta does not and yet the baby needs even more nutrients. Inadequacy of the placenta puts the baby at risk of starvation. For this reason, doctors give it up to 42 weeks, if the dates were accurate, then induce labour.

A friend complained about pain in her lower abdomen during her 40th week and was quite frantic about it. The doctor explains that these pains are called trial labour pains, similar to menstrual pains. They neither go away nor increase, they are not normal, but are part of pregnancy and medically called Braxton-Hicks pain.

In cases of post-term pregnancy, the delivery is likely to be difficult. “The bones of the baby are harder and it is difficult to manoeuver through the birth canal,” Dr. Kagawa says. These babies may also not be as healthy or robust as those born on time and are kept in the neonatal health care unit for monitoring for some time.