A blighted ovum, also called an anembryonic pregnancy, is a type of early miscarriage where a fertilized egg implants in the uterus and a gestational sac forms, but an embryo never develops inside it. It is one of the most common causes of miscarriage in the first trimester. What makes it particularly disorienting is that your body doesn’t know the pregnancy isn’t viable. The placenta and empty sac continue releasing pregnancy hormones, so you may feel pregnant, test positive, and have no reason to suspect anything is wrong until an ultrasound reveals an empty sac.
Why It Happens
Most blighted ovums are caused by chromosomal abnormalities in the fertilized egg. Very early in development, something goes wrong with cell division, and the cluster of cells that would become the embryo stops growing. The cells that form the placenta and gestational sac, however, may continue developing normally for a time. This is why a pregnancy sac appears on ultrasound even though there’s no embryo inside it.
This isn’t caused by anything you did or didn’t do. It’s not linked to exercise, stress, diet, or anything within your control. It reflects a random genetic error during fertilization, the kind that becomes more common with age but can happen to anyone. In most cases, it’s a one-time event with no bearing on future pregnancies.
What It Feels Like
That’s part of what makes a blighted ovum so difficult: for weeks, it feels like a normal pregnancy. You may have breast tenderness, nausea, fatigue, and a positive pregnancy test. Your body is responding to the hormones produced by the placenta, and those hormones don’t distinguish between a viable and nonviable pregnancy.
Many people don’t experience any warning signs at all until the condition is found on an early ultrasound, often between 7 and 9 weeks. Others eventually begin to miscarry on their own, with symptoms that include vaginal spotting or bleeding, passing light gray tissue or blood clots, and mild to moderate cramping in the pelvic and abdominal area. Pregnancy symptoms like morning sickness may also start to fade as hormone levels drop.
How It’s Diagnosed
A blighted ovum is diagnosed by transvaginal ultrasound. The key finding is a gestational sac with no visible embryo inside. Because very early pregnancies can sometimes look empty before the embryo is large enough to see, doctors use specific size thresholds to avoid misdiagnosis. Current guidelines published in The New England Journal of Medicine recommend that the sac must measure at least 25 mm across (roughly one inch) with no embryo before a definitive diagnosis of pregnancy failure is made.
If the sac is smaller than that, your provider will typically wait one to two weeks and repeat the ultrasound. This follow-up scan confirms whether the sac has continued to grow without an embryo or whether an embryo has appeared. The waiting period can be emotionally grueling, but it exists to prevent misdiagnosing a pregnancy that’s simply earlier than expected.
Blood tests measuring hCG (the hormone detected by pregnancy tests) can also provide clues. In a healthy pregnancy, hCG levels roughly double every two to three days in the early weeks. With a blighted ovum, levels may rise more slowly, plateau, or begin to drop. But hCG alone can’t confirm the diagnosis. Ultrasound is the definitive tool.
Treatment Options
Once a blighted ovum is confirmed, there are three paths forward. The right choice depends on how far along the pregnancy is, your physical health, and your personal preferences. All three are medically safe for most people in the first trimester.
Waiting for a Natural Miscarriage
Some people choose to let the body pass the pregnancy tissue on its own, an approach called expectant management. When given enough time (up to about eight weeks from diagnosis), roughly 80% of people will complete the process without intervention. The experience involves cramping and bleeding that may last several days. This option avoids medication and surgery, but the timeline is unpredictable, and some people find the waiting emotionally difficult.
Medication
Medication can help the body expel the tissue more quickly. The standard approach uses a vaginal medication that causes the uterus to contract and empty. About 71% of people complete the process after the first dose within three days, and that number rises to about 84% by eight days. When a second oral medication is given 24 hours beforehand, success after one dose improves to roughly 84%. The process involves cramping and bleeding, typically heavier than a normal period. The complication rate is low, under 1% in clinical studies. If the medication doesn’t fully work, a surgical procedure may follow.
Surgical Procedure
A suction procedure (called a D&C) is the quickest option and has been the standard surgical approach for early pregnancy loss before 13 weeks. It’s a short outpatient procedure performed under sedation. Success rates are high, above 90%. The risks, while uncommon, include bleeding, infection, and in rare cases, scarring inside the uterus. This option is also used when bleeding is heavy or there are signs of infection that make waiting unsafe.
Recovery and Future Pregnancy
Physical recovery after a blighted ovum is generally quick regardless of which treatment path you take. Bleeding may continue for one to two weeks. Most people get their period back within four to six weeks, and ovulation can return even before that first period.
Having a blighted ovum does not reduce your chances of a successful pregnancy in the future. Most people who experience one go on to have completely normal pregnancies. A single miscarriage of any type, including a blighted ovum, is not considered a sign of an underlying fertility problem. If you experience three or more miscarriages in a row, further evaluation is recommended to look for contributing factors, but that pattern is uncommon.
The emotional recovery often takes longer than the physical one. A blighted ovum is a real pregnancy loss, even though an embryo never formed. Grief, confusion, and frustration are all normal responses, especially when the diagnosis comes as a complete surprise during what seemed like a healthy pregnancy.