You have given birth to your baby and now you are in theatre surrounded by obstetricians, vascular surgeons,
gynaecological oncologists, haematologists, radiologists, neonatologists, anaesthetists and urologists. It’s a large team of specialists and you’re wondering what is going on (and why you need them all there). You’ve got placenta accreta.
What is placenta accreta?
Placenta accreta is a rare condition – there are estimated to be in the region of one in 500 to 2,500 cases in Australia each year – and is a severe obstetric complication that involves a deep attachment of the placenta into the middle layer of the uterine wall. ‘In simple terms placenta accreta is an abnormally adherent placenta; it is very stuck,’ explains Dr Andrew Carlin, the acting director of the Maternal Fetal Medicine Unit at the John Hunter Hospital in Newcastle, NSW. ‘Placentas usually separate from the mothers within 30 minutes at most.’
Types of placenta accreta
There are three main types:
• Placenta accreta involves an invasion of the myometrium (middle layer of uterine wall), which doesn’t penetrate the entire muscle. This form occurs in 75 to 78 percent of cases.
• Placenta increta is when the placenta extends further into the myometrium and happens in about 17 percent of cases.
• Placenta percreta is the worst of the lot and comes about when the placenta goes through the muscles and breaches the covering layer. It can then attach to other organs such as the bladder and sometimes onto the bowel or anterior abdominal wall. It is estimated that this form occurs in five to seven percent of cases.
Who can get it?
No-one knows why it occurs and unless there has been a problem in previous pregnancies or other risk factors are known there is usually no warning. Dr Carlin explains, ‘Any woman who has had a previous Caesarean and a low placenta is at risk and therefore requires careful evaluation of the placental location.’
For Rebecca Catton, 31, a past Caesarean may have contributed to her placenta percreta. Her birth experience with her first child, Jessyka, now eight, was not quite what she had hoped for.
‘I was 41 weeks and three days pregnant when I went into hospital to have an induction. The staff induced me four times over the Tuesday, Wednesday and Thursday, and I never dilated despite having contractions,’ she explains.
By the Friday a Caesarean was suggested. ‘I was totally over it and beyond tired by this stage so I agreed,’ she says.
Rebecca went on to have two more children without complications, Lachlan, four, and three- year-old Isobella, but it was with her fourth pregnancy that the problem arose. Rebecca was diagnosed with placenta previa (an obstetric complication in which the placenta is attached to the uterine wall or close to covering the cervix) at around 13 weeks into her pregnancy, but it didn’t cause concern to her doctor till her 22-week scan when it was mentioned: ‘I went to the doctor and asked about it a few times, but always got the same response – that it was rare and probably not a problem.’
Rebecca had more ultrasounds (they’d lost a twin in the early stages of the pregnancy) and kept asking till finally her doctors said she did not have to worry. ‘I was relieved and felt like I could enjoy being pregnant,’ she says.
Rebecca was advised to give birth to Lola early because of her history and was required to go under a general anaesthetic.
‘I was wheeled into surgery where David, my husband, was not allowed in with me – we never even got to say goodbye to each other. The doctors placed a mask over my face to put me to sleep.
I can remember looking around the room and wondering why there were 30 plus people there. Then I was out,’ she explains.
Rebecca woke up in pain and was told she had had a hysterectomy due to her placenta percreta. ‘I’d lost four litres of blood (the average human body holds between four and five litres) and had to have four units of blood, two units of plasma and a few more units of fluid to keep me going,’ she says. It was only later that she was told that she had had a Caesarean hysterectomy.
What are the treatment options?
There are a number of treatment options and these vary depending on the condition of the placenta accreta. These options include:
• If the placenta accreta is known or suspected, the woman’s delivery is planned very carefully. ‘A multi-disciplinary team of obstetricians, gynaecological oncologists, radiologists, vascular surgeons and sometimes anaesthetists, urologists, haematologists and neonatologists are involved,’ explains Dr Carlin.
• Another option is to have the baby delivered through the top of the uterus rather than the front, then to assess the placenta. If the placenta is stuck then it is usually left in. This is known as conservative management and patients can choose this option to preserve their fertility. The cord is cut and the uterus is stitched up. The patient then usually has a radiological procedure to close the large vessels supplying the uterus to minimise blood loss. This is most commonly done in theatre, on the table if bleeding is heavy, or it can be performed after the operation in the interventional radiology suite (and is usually a single procedure).
‘The risks then are of bleeding and infection – sometimes several days or even weeks after the operation,’ explains Dr Carlin. After several months, if all goes well, the placenta progressively shrinks away.
• A Caesarean followed by hysterectomy (otherwise known as Caesarean hysterectomy) is another option. ‘This is a big operation but
it reduces the risks of delayed infection and bleeding,’ explains Dr Carlin. ‘This has been the gold standard for some time but causes infertility.’ For Rebecca this was the best choice because they could not stop the bleeding. ‘The placenta had grown through my uterus and had attached to my bladder. The only choice was to lose my uterus to save my life.’
• Another approach is the “extirpative method”, which is forced manual removal (by hand in the uterus) of the placenta after delivery. Dr Carlin explains this method is no longer used by sensible obstetricians as it’s considered too dangerous due to the risks of uncontrollable and life-threatening bleeding.
What about afterwards?
Luckily there are no immediate risks to the newborn with placenta accreta as the problems usually start after the baby has been delivered, when the placenta is found to be adherent. Generally, if picked up early, both the mother and baby will be OK. This is due to the range of technology and specialists we have available today in Australia.
‘We have managed several patients with placenta accreta at the John Hunter since I arrived in July 2008,’ says Dr Carlin, ‘and so far all cases have been successful – mothers and babies alive and well, and in most cases with the uterus still intact.’