How long can baby can stay in mum’s tum?
Most of us are aware that premature delivery of a baby can cause problems, but few people appreciate the catastrophe that can occur when a baby is delivered too late and suffers hypoxic-ischaemic brain injury. We seem to have this idea that once a baby gets to its due date, then everything must be fine because normal development has taken place.
It’s such a curious idea. After all, no-one thinks it’s alright to leave muffins in the oven once they’ve cooked, so why would anyone think a baby can remain in mum’s tum long after its due date? I’ll explain why it can be a major problem…
The boy who got baked for too long
Have a look at these brain scans of a 6-year old boy; I’ll call him Sipho for our purposes. Sipho was delivered just over four weeks late and suffered massive brain injury due to impaired oxygen supply to his brain, what we call hypoxic-ischaemic brain injury (HIBI). The image below is a sagittal section and it’s easy to see familiar features such as his eyes and nose.
I have labelled major anatomical landmarks as follows:
- Brain tissue.
- Brain stem.
- Lateral ventricles.
- Cerebellum.
This numbering applies to all the MRI images in this post. Sipho doesn’t have control over his head and neck, so it was necessary to tilt his head back and upwards when doing the scan, resulting in some unusual angles on some of the scan slices.
The lateral ventricles are hollow spaces within the brain filled with cerebrospinal fluid. In Sipho’s brain, the lateral ventricles are enormous because there is so little brain tissue left. In fact, normally you cannot see the lateral ventricles on a midline sagittal view, like this image (Figure 1). For example, the scan below (Figure 2) is of a normal, healthy adult’s brain and the lateral ventricles cannot be seen. Got it? In comparison to a healthy brain, Sipho’s cerebellum and brain stem are quite atrophied; compare the gap between the cerebellum and the brain stem in the normal brain to that of Sipho’s brain. Can you see the difference?
Here is another view of Sipho’s brain, this time an axial section (Figure 3). This slice is above the level of the brain stem and cerebellum, so you can’t see those components, but you can still see the massive lateral ventricles. As is apparent, more than half of the skull cavity is taken up by fluid—there is very little brain in there.
As a technical point for anatomically inclined readers, it might be appreciated that because of how Sipho’s head had to be tipped up to do the scan, the anterior part of this axial slice runs from just above his eyes, but the posterior part of the slice cuts through the parietal lobes and not the occipital lobes, as you might expect. (Not that there are really any lobes to speak of at the back of his brain, but you get the idea.)
The Devastation of Hypoxic-Ischaemic Brain Injury
Label 1 points to “brain tissue” but in this context the term is a little misleading. What we’re seeing is not really brain tissue in the usual sense of the term. It’s a soft mush of fluid-filled cavities interspersed with neurons and glia, what we call polycystic encephalomalacia, meaning brain tissue that has gone soft and that is now filled with multiple cystic cavities. You see, little Sipho doesn’t really have a brain, at least as we normally understand that concept. He is kept alive by his brain stem, and the little cognitive and emotional processing that does occur is mainly a function of his cerebellum.
How did such a terrible thing happen?
This is the (short) story of little Sipho, the boy who got baked for too long. His pregnant mother, let’s call her Lerato, was HIV-positive and she knew that there was a risk to her baby and carefully followed all the advice she got from the antenatal clinic. Lerato was busy with other things when her due date arrived. She felt fine, so why should there be a problem? No-one at the antenatal clinic had told her that it could be detrimental to the baby if it was delivered late, so she didn’t go to hospital on that day. This was the first mistake.
The second mistake was that she only went to the hospital 22 days after she was due. Unfortunately, the state hospital she attended was full and she was told that she should go home. She was given a letter by the doctor instructing her to return at the end of the month for an elective caesarean section. This would have been 29 days past her due date and was the third and critical mistake.
Placental Insufficiency
By now Lerato had passed a threshold and her placenta was starting to give in; it’s called placental insufficiency. Unbeknownst to her, her infant was gradually being suffocated inside her because he was not getting enough oxygen. She went home and began to show a few days later, so she returned to hospital. Labour was prolonged and she was not immediately delivered by the hospital staff, despite being so overdue. Only three days later was a caesarean delivery done. This was the fourth mistake and the doctors were later found guilty of medical negligence. By the time she gave birth, Lerato was 29 days overdue and Sipho’s fate was sealed.
Little Sipho did not cry at birth and he was taken away immediately after delivery. When Lerato saw him the next day, he had on an oxygen mask and was being fed via a nasogastric tube. His mother was given no information. She was sent home two days later but he was only discharged three weeks later.
Malnourishing the Baby
Remarkably, before discharge the nasogastric tube had been removed by the doctors but Sipho was still not feeding; the fifth mistake. After a few days, Lerato took the baby back to hospital and was referred to the speech therapists (who treat swallowing problems), but they could not get him to eat, so they referred him to the occupational therapists, who in turn referred him to the physiotherapists; mistakes six and seven. In effect, what was happening at that stage was that they were starving a seriously brain-damaged infant. Of course, malnutrition would only have worsened the situation.
Quadriplegia
Remarkable, eventually Sipho did start to suckle and as a result he survived. He never learnt to crawl, and he still struggles to roll over onto his side. He can only control his head movements for a few seconds. He has no control over his limbs and is suffering from what we call spastic quadriplegia. This is the most severe form of cerebral palsy.
Cortical Blindness
At some stage it occurred to his mother that he did not seem to be able to see properly, and indeed, little Sipho is completely blind. He has what is called cortical blindness. His eyes developed normally, but when he suffered the brain damage, the occipital lobes were destroyed. Normally, the optic nerves terminate in the occipital lobes, but now they terminate in a fluid-filled space. You can see this clearly in the coronal section of his brain shown below (Figure 4).
Epilepsy & Aphasia
Sipho did not attain any of his developmental milestones. He cannot talk because of the brain damage; he is aphasic. He can hear and briefly smiles at the sound of his mother’s voice. He sometimes moans in distress but Sipho never laughs. At two years of age he developed epileptic seizures. His growth has been stunted because his hypothalamus was damaged by the hypoxic-ischaemic brain injury and he does not produce sufficient growth hormone.
Depressed Mother
His mother has had to give up her job because Sipho is completely dependent on her and needs 24-hour care. Sipho’s father abandoned her and the child once he realised that there was something wrong with Sipho. Lerato has almost no emotional support and is suffering from major depressive disorder.
The Danger of Ignorance
All this happened because neither Lerato, nor the nurses, nor the doctors understood the dangers of an infant being delivered too late. This catastrophe could have been avoided if all the parties involved had a little more knowledge. So let’s spread the word; postmaturity delivery can be dangerous when left too long and can cause hypoxic-ischaemic brain injury. Don’t let this happen to another baby again.
Reality Check
Lastly, please be quite clear that I am not suggesting that a few days on either side of the due date is a problem. The due date is an estimate anyway and our biology allows for variation. Damage arises when a child is born far too soon or far too late. In my experience, four weeks postmature is far more serious than four weeks premature. Premature babies can and do continue developing after birth and for the majority there are no long term consequences. However, there is no coming back from placental insufficiency due to postmaturity, which causes permanent and usually devastating brain damage.
