18 Nov Blighted ovum – the silent miscarriage?
A blighted ovum is an early pregnancy failure. Strictly speaking, it’s a miscarriage. But that’s confusing: a blighted ovum exists before any bleeding happens. It’s often spotted late, or not at all. So a blighted ovum is sometimes called a silent miscarriage. One in two early miscarriages are due to a blighted ovum – it’s that common.
Is blighted ovum an accurate description? No. First, the word ‘blighted’ is biologically incorrect – it’s a cellular or chromosomal failure. Second, the ‘ovum’ is not solely to blame: it’s the egg AND sperm that don’t speak to each other. And third, a silent miscarriage also refers to an embryo with no heartbeat. That’s not what a blighted ovum is.
A better name for a blighted ovum is anembryonic pregnancy. While the gestational sac continues to grow – often into a slightly irregular, sagging shape – the embryo does not. It’s particularly upsetting for women who knew, or thought, they were pregnant.
Those women include fertility patients, who would have religiously done a home pregnancy test 14 days after their embryo transfer. A few weeks later, at their early ultrasound scan, they’re given the sad news.
But women who conceive naturally rarely have early scans. So a blighted ovum may not be discovered till 12 weeks. You may have had pregnancy symptoms, adding to the sense of devastation when it’s diagnosed. Bleeding and cramping, a common way for an anembryonic pregnancy to end, doesn’t always happen.
So what happens when a blighted ovum is diagnosed? Patients are usually advised to let the miscarriage end naturally. Drugs are sometimes prescribed. Fertility patients will be told to stop their medication. But some women will need an operation to remove the pregnancy – effectively a termination. This is more common when diagnosis is late.
Are there any known blight ovum risk factors? It’s usually genetic – so not much you can do there. Sperm DNA fragmentation may increase the risk, so an up-to-date semen analysis and PICSI or MACS may help.
There’s also a link to high BMI and alcohol use, so reduce your weight and stop drinking if you can. An irregular uterus may also be a risk factor, so ensure you have a trans-vaginal scan before trying to conceive.
Immunology issues, hormonal irregularities and blood disorders raise the miscarriage risk more generally, so ask your doctor or clinic to check for these. And taking steps to improve your diet may reduce the chance of a blighted ovum or other type of miscarriage.
For women who think they’re pregnant, naturally or via IVF, an early scan in week 6 is a good idea. As well as checking for a blighted ovum, the scan will pick up an ectopic pregnancy. Identifying either at this stage is safer.
If you experience a blighted ovum, allow yourself time to grieve for the loss of your precious pregnancy. Don’t let anyone tell you that an early miscarriage is not as bad as a late one. It’s perfectly normal to feel devastated.
Will a blighted ovum happen again? It’s unlikely. But the fact remains that other forms of miscarriages can occur, and older women are more prone to them. Speak to your doctor. And if you’ve had IVF treatment, read our tips on reducing your chances of a miscarriage.