A positive pregnancy test can shift your whole week—sometimes your whole life. Then an ultrasound report says “empty sac”. Many parents immediately search one phrase: blighted ovum. What does it mean, what happens next, and how do you stay safe while decisions are made?

A blighted ovum (anembryonic pregnancy) is an early pregnancy loss where the gestational sac develops in the uterus, but the embryo does not develop in a way that can be seen. Symptoms can still feel “normal” for a while, which makes the diagnosis especially confusing.

Blighted ovum explained in clear terms

What a blighted ovum is (anembryonic pregnancy, “empty sac”)

A blighted ovum happens when implantation occurs and the gestational sac starts forming, but an embryo never forms—or stops developing extremely early. The medical term is anembryonic pregnancy. On ultrasound, clinicians often describe an empty gestational sac.

Why can you still feel pregnant? Early placental tissue (the trophoblast) may keep producing hCG (human chorionic gonadotropin) for a short time. So nausea, breast tenderness, fatigue, and a positive pregnancy test can persist even though the embryo is not developing.

Sometimes a yolk sac is seen first and then development stops. If dates are uncertain (late ovulation, irregular cycles), a repeat scan is usually planned before confirming the diagnosis.

How it differs from miscarriage, missed miscarriage, and chemical pregnancy

“Miscarriage” refers to pregnancy loss before 20 weeks. A blighted ovum is one specific type.

A missed miscarriage also means the pregnancy is no longer viable but has not yet been expelled. Ultrasound helps differentiate:

• Missed miscarriage: an embryo was present, but there is no heartbeat or expected growth.
• Blighted ovum: the sac develops, but no embryo is visible at a time when one is expected.

A chemical pregnancy ends even earlier—after a positive test but before an ultrasound can confirm a gestational sac.

Blighted ovum vs ectopic pregnancy vs molar pregnancy

A blighted ovum is inside the uterus. An ectopic pregnancy implants outside the uterus (often in a tube) and can become an emergency if it ruptures. Symptoms can overlap, hCG alone cannot reliably distinguish them, so ultrasound follow-up matters.

A molar pregnancy is abnormal placental tissue growth (gestational trophoblastic disease). Ultrasound and hCG patterns look different, and follow-up is specific.

How common a blighted ovum is

Early pregnancy loss occurs in roughly 15% of clinically recognised pregnancies, and the true number is higher because many losses happen before a scan. Anembryonic pregnancies are a common cause of first-trimester loss.

Age influences risk because chromosomal errors become more common over time, especially after 35 and further after 40.

Many blighted ovum diagnoses are made around 7–9 weeks, often at a dating scan or after bleeding.

What causes a blighted ovum

Chromosomal abnormalities and genetic factors

The most common cause of blighted ovum is a chromosomal abnormality in the fertilised egg (for example aneuploidy, meaning extra or missing chromosomes). In many cases, this is random and unpredictable.

More rarely, a parent may carry a balanced chromosomal rearrangement (such as a balanced translocation). This is usually discussed when losses are recurrent.

What happens after implantation

Implantation can trigger early pregnancy changes: the sac forms, trophoblastic tissue grows, and hCG rises. But the embryo fails to develop or stops extremely early. Ultrasound later shows sac growth without a visible embryo.

Other factors sometimes discussed (less common)

Depending on your history, clinicians may also consider:

• Uterine cavity anomalies (septum, adhesions, fibroids distorting the cavity)
• Selected autoimmune or clotting-related mechanisms
• Certain infections

Sometimes, no single clear factor is identified.

Risk factors that can increase the chance of a blighted ovum

• Advanced maternal age
• Repeated early losses (discussion of recurrent pregnancy loss evaluation)
• Thyroid disease, poorly controlled diabetes
• Obesity
• Uterine anomalies or fibroids affecting the cavity
• Smoking, alcohol, exposure to certain toxins (some solvents, pesticides, heavy metals)

Many people with a blighted ovum have none of these.

Blighted ovum symptoms and when to get help

Symptoms that can still happen (and why they may fade)

Early pregnancy symptoms may continue because hCG can persist for a while. Then symptoms may fade as hormone levels plateau or fall. A symptom change alone cannot confirm a blighted ovum—imaging follow-up provides clarity.

Bleeding, cramps, and pelvic pain

Spotting or bleeding may occur as the body begins to end the pregnancy: brown discharge, red bleeding, clots, or tissue passage. Cramping can feel like period pain and may intensify when tissue passes.

When there are no symptoms

Some diagnoses are made during routine ultrasound with no bleeding or pain.

Urgent warning signs

Seek urgent medical care if you have:

• Bleeding soaking more than two pads per hour for two hours
• Severe or worsening pelvic/abdominal pain
• One-sided pain, especially if increasing
• Dizziness, fainting, marked weakness
• Fever, chills, foul-smelling discharge, or feeling very unwell

How a blighted ovum is diagnosed

Ultrasound: the key test

Transvaginal ultrasound is commonly used early in pregnancy because it gives better detail. The typical finding is an intrauterine gestational sac without an embryo. A yolk sac may be present or absent.

Mean sac diameter (MSD): avoiding a wrong diagnosis

Clinicians may use mean sac diameter (MSD) thresholds to avoid misdiagnosing a very early viable pregnancy. A commonly used transvaginal criterion is an MSD around 25 mm with no embryo seen, supporting nonviability. Protocols differ slightly, and imaging quality matters—so repeat scans are common when dates are uncertain.

hCG trends: useful, but not decisive alone

Serial quantitative hCG can support follow-up, but one number cannot confirm viability. With blighted ovum, hCG may rise slowly, plateau, or fall, and can remain elevated for a time.

Why repeat ultrasound is often planned

When the first scan is early or unclear, a repeat scan is usually scheduled (often about 7–14 days later, depending on what was seen). The goal is simple: confirm lack of progression before any intervention.

Ruling out ectopic pregnancy

If an intrauterine pregnancy is not clearly seen, clinicians consider pregnancy of unknown location and rule out ectopic pregnancy using ultrasound assessment and hormone follow-up.

Treatment options for a blighted ovum

There are three accepted approaches. Choice depends on bleeding, pain, infection risk, scan findings, your health history, access to follow-up, and personal preference.

Expectant management (waiting)

Waiting allows the body to pass tissue naturally. It may take days to weeks. Bleeding can start light and become heavier with cramping when tissue passes. Follow-up is needed because the process can be incomplete.

Medical management (misoprostol, sometimes mifepristone)

Medical management often uses misoprostol to help the uterus contract and expel tissue. Some protocols add mifepristone beforehand.

What you may feel:

• Strong cramps for a period of time
• Bleeding heavier than a usual period, often with clots

Follow-up (symptoms, ultrasound, and/or hCG) checks completion.

Surgical management (suction aspiration/D&C)

Surgical management is usually suction aspiration (often called D&C in common language). It is generally outpatient and the quickest option. It may be advised for heavy bleeding, suspected infection, anaemia risk, or if expectant/medical care has not completed.

Rh status and anti-D

If you are Rh-negative, anti-D (Rh immune globulin) may be offered after miscarriage or uterine procedures, depending on gestational age and local protocol.

What to expect during treatment and follow-up

Bleeding and cramping patterns

• Expectant: bleeding may last days to a few weeks, heavier when tissue passes
• Medical: bleeding often starts within hours and can be heavy initially, then tapers
• Surgical: bleeding is often lighter and shorter afterwards

Seek care quickly if bleeding becomes very heavy or you feel faint.

Pain relief and comfort at home

Ibuprofen or paracetamol may help if suitable for you. Heat packs, rest, and good hydration support comfort. Use pads during bleeding to reduce infection risk.

Confirming completion

Completion may be confirmed by symptom improvement, ultrasound, and/or falling hCG. Contact your clinician promptly for fever, worsening pain, foul discharge, or persistent heavy bleeding.

Complications and when to seek care

• Heavy bleeding and possible anaemia: dizziness, fainting, breathlessness, ongoing exhaustion after heavy loss
• Infection: fever, chills, worsening abdominal pain, foul discharge
• Retained tissue: prolonged bleeding/cramps, persistent positive pregnancy tests, fever

Physical recovery after a blighted ovum

Cramping often settles within about a week. Bleeding commonly tapers over 1–2 weeks, sometimes longer.

A period often returns in 4–6 weeks. Ovulation can occur before the first period, so pregnancy can happen quickly. Pregnancy tests may stay positive for a while because hCG takes time to fall.

Resume daily activities as you feel able. Use pads, not tampons, until bleeding stops. Sex is usually postponed until bleeding has resolved and you feel ready.

Emotional recovery and supportive care

A blighted ovum can bring grief, anger, guilt, numbness, or sudden mood shifts. Hormonal changes can amplify emotions. Partners may cope differently—one may want to talk, the other may go quiet and focus on tasks.

Support can come from your gynaecologist, counsellor, or a pregnancy-loss support group. If sleep and appetite are severely affected, daily functioning is slipping, or you feel unsafe, mental health support should be arranged.

Getting pregnant again after a blighted ovum

When to try again

Many clinicians suggest waiting until at least one normal cycle has passed for easier dating and recovery of the uterine lining. Personal readiness matters just as much.

Chances of a healthy pregnancy

Most people go on to have a healthy pregnancy after a single blighted ovum.

When to ask about evaluation

If there are two consecutive miscarriages (or three, depending on protocol), clinicians often discuss evaluation for recurrent pregnancy loss, including uterine imaging, thyroid tests, diabetes screening, and selected autoimmune/clotting tests.

Preventing early pregnancy loss: what can and can’t be controlled

You cannot fully prevent blighted ovum because many cases are caused by random chromosomal changes. Still, preconception care supports overall pregnancy health:

• Folic acid (often 400–800 micrograms daily unless advised otherwise)
• Medication and supplement review
• Optimising thyroid disease and diabetes
• Avoiding smoking and alcohol when trying to conceive
• Limiting exposure to solvents, pesticides, and heavy metals where possible

Key takeaways

• A blighted ovum (anembryonic pregnancy) is an early loss where a gestational sac forms in the uterus but no embryo develops.
• Symptoms and a positive test can continue temporarily because hCG may persist.
• Diagnosis relies on transvaginal ultrasound, often with a planned repeat scan, hCG trends support follow-up but cannot confirm viability alone.
• Treatment options include expectant care, medication (often misoprostol), or a procedure (suction aspiration/D&C), with follow-up to confirm completion.
• Seek urgent care for very heavy bleeding, severe or one-sided pain, dizziness/fainting, fever, chills, or foul-smelling discharge.
• Physical recovery often takes weeks, emotional recovery may take longer. Professionals can support you, and you can download the Heloa app for personalised guidance and free child health questionnaires.

Questions Parents Ask

Can a blighted ovum be misdiagnosed because it’s “too early”?

Yes—when ovulation or implantation happened later than expected, an ultrasound can show an “empty sac” before the embryo is visible. That’s why many clinicians plan a repeat transvaginal scan (often 7–14 days later) before confirming a blighted ovum. If you’re unsure about dates, it’s completely normal to want that extra confirmation for peace of mind.

What are the chances of another blighted ovum in a future pregnancy?

In most cases, a blighted ovum is caused by a one-time chromosomal issue and does not mean it will happen again. Many parents go on to have a healthy pregnancy afterward. If early losses happen repeatedly, you can ask your healthcare team about additional evaluation (for example, uterine imaging or selected blood tests) to look for treatable factors.

Should the pregnancy tissue be tested after a blighted ovum?

Sometimes it can be. Testing may identify a chromosomal cause, which can feel reassuring because it confirms nothing you did caused the loss. It isn’t always necessary after a first loss, and it may not always be possible (especially with expectant or medical management). If you’re considering it, you can discuss availability, cost, and whether results would change next steps for you.

Further reading :

• Blighted ovum: What causes it? (https://www.mayoclinic.org/diseases-conditions/pregnancy-loss-miscarriage/expert-answers/blighted-ovum/faq-20057783)
• Anembryonic Pregnancy – StatPearls – NCBI Bookshelf – NIH (https://www.ncbi.nlm.nih.gov/books/NBK499938/)