Blighted Ovum: Complete Guide
A blighted ovum, also called an anembryonic pregnancy, is a common type of early miscarriage where a gestational sac forms but no embryo develops inside it. It's usually only discovered at a routine early scan, which can make the diagnosis feel especially sudden and confusing. This guide covers what causes it, how it's diagnosed, and what your options are afterwards.
What happens with a blighted ovum
In a typical early pregnancy, a fertilised egg implants and develops into both a gestational sac and an embryo. With a blighted ovum, the sac and placental tissue continue to form — which is why a pregnancy test stays positive and early symptoms like nausea or breast tenderness can carry on as normal — but the embryo itself stops developing very early on, often before it's ever visible.
- The cause is almost always a chromosomal abnormality in the fertilised egg, meaning the cells couldn't organise properly into an embryo.
- It is not caused by anything you did, ate, or didn't do — exercise, lifting, sex, and stress do not cause this.
- It's thought to account for a significant proportion of early first-trimester losses, many of which happen before a person even knows they're pregnant.
- Most people who experience a blighted ovum go on to have a straightforward, healthy pregnancy afterwards.
How it's diagnosed and confirmed
A blighted ovum is diagnosed by ultrasound, usually at a dating or early reassurance scan. The sonographer will see a gestational sac that has grown to a size where a fetal pole (the earliest visible sign of an embryo) should normally be seen — but isn't.
- Because early pregnancy dating isn't always exact, a single scan showing an empty sac is often not enough on its own for a firm diagnosis.
- A follow-up scan is typically offered 7–14 days later to check whether the sac has grown and whether an embryo has since become visible.
- If the sac remains empty at the second scan and has grown as expected, the diagnosis is confirmed.
- Blood tests tracking hCG levels can sometimes support the picture, though ultrasound remains the main diagnostic tool.
Your options for management
Once confirmed, there are three main ways to manage a blighted ovum, and the right choice depends on your preferences, how you're feeling physically, and any medical advice specific to your situation.
- Natural management — waiting for your body to miscarry on its own, with monitoring from your care team.
- Medical management — taking medication (usually misoprostol, sometimes combined with mifepristone) to help the body pass the pregnancy tissue at home or in hospital.
- Surgical management — a procedure (often called an ERPC or surgical management of miscarriage) to remove the tissue under anaesthetic, usually chosen if bleeding is heavy, tissue hasn't passed naturally, or it's the person's preference.
Your midwife or the early pregnancy unit will talk through the pros and cons of each option for your specific circumstances, and there's no single "right" choice.
Frequently Asked Questions
What causes a blighted ovum?
A blighted ovum is caused by a chromosomal abnormality in the fertilised egg, meaning the cells that should have formed an embryo didn't develop properly, even though the gestational sac and placental tissue continued to grow. It isn't linked to anything the pregnant person did, and it isn't a sign of a wider fertility problem. Most people go on to have healthy pregnancies afterwards.
Can a blighted ovum be misdiagnosed?
Because early dating can vary and embryos can sometimes be too small to see clearly at a very early scan, doctors are usually cautious about diagnosing a blighted ovum from a single scan alone. This is why a follow-up scan a week or two later is standard practice before confirming the diagnosis, to avoid ending a pregnancy that might still be developing normally. If your dates are uncertain, it's reasonable to ask for a repeat scan before deciding on management.
Will a blighted ovum happen again?
For most people, a blighted ovum is a one-off event caused by a random chromosomal error, and it doesn't increase the risk of it happening in a future pregnancy by very much. If you experience recurrent early losses (usually defined as three or more in a row), your GP or midwife can refer you for further investigation. A single blighted ovum on its own doesn't usually warrant additional testing before trying again.
This article is for informational purposes only and does not constitute medical advice.
Related articles: