Empty Sac at 9 Weeks: Understanding Blighted Ovum and Pregnancy

Understanding pregnancy can be complex, and when things do not go as expected, it can lead to confusion and worry especially if its your first pregnancy.

This article aims to shed light on the phenomenon of an “empty sac” in pregnancy, specifically at 9 weeks when you have your first ultrasound.

Here, we’ll delve into terms like “blighted ovum” and “empty gestational sac”, presenting clear, accessible information for those who need it.

Whether you’re supposed to be 9 weeks pregnant and facing this issue or simply want to be more informed, this article is worth reading.

What is a Blighted Ovum?

A blighted ovum, also known as anembryonic pregnancy, is a type of early pregnancy loss.

It occurs when a fertilized egg implants into the uterus, and the placenta and pregnancy sac develop, but the embryo does not.

Despite the absence of an embryo, the pregnancy sac can still grow, leading to positive home pregnancy test results and symptoms of early pregnancy.

What Causes a Blighted Ovum?

A blighted ovum is usually due to chromosomal abnormalities in the fertilized egg. These abnormalities can occur at random during the fertilization process and are not typically linked to the parents’ genetic material.

Therefore, it’s important to remember that when they diagnose a blighted ovum,  this type of pregnancy loss is not anyone’s fault.

Understanding an Empty Sac

Early in pregnancy, around 6 weeks, an ultrasound will typically show a small sac in the uterus. Inside this sac, a yolk sac and a tiny structure called the fetal pole should be visible.

However, in cases of a blighted ovum, the sac is empty – no yolk sac or fetal pole can be spotted. An empty sac in this context means the embryo has either stopped developing or was never present.

What Does an Empty Sac Mean at 9 Weeks?

By the 9th week of pregnancy, an ultrasound should clearly show the developing baby. If the sac is empty at 9 weeks, it is likely a case of blighted ovum .

It’s essential to remember that the diagnosis should not be made based on a single ultrasound. Often, another ultrasound later is recommended to confirm.

Symptoms of a Blighted Ovum

Initial symptoms of a blighted ovum may mimic those of a normal pregnancy because the body does not immediately recognize the pregnancy isn’t viable.

This can include missed menstrual periods, positive pregnancy tests, and common early signs of pregnancy like fatigue and nausea.

However, as the body begins to realize there’s no embryo developing, pregnancy symptoms may fade.

Other symptoms can include spotting or bleeding, cramps, or the passing of tissue. These can be similar to symptoms of a natural miscarriage.

How is a Blighted Ovum Diagnosed?

A blighted ovum is typically diagnosed during a routine ultrasound in the early weeks of pregnancy, often around the 6-7 weeks mark, but sometimes as late as 9 or 10 weeks.

When an empty gestational sac is detected, the healthcare provider will likely schedule another ultrasound later to confirm the diagnosis.

This is because the embryo might just be smaller than expected and might become visible later.

Blood tests to measure human chorionic gonadotropin (hCG), the pregnancy hormone, can also assist in the diagnosis.

With a blighted ovum, hCG levels might increase initially but then decrease or plateau instead of doubling every few days as expected in a healthy pregnancy.

Ultrasound Findings: Empty Gestational Sac

On an ultrasound, an empty gestational sac appears as a sac with well-defined borders but you don’t see anything in the sac. No embryo, yolk sac or fetal pole is visible.

The size of the sac is also considered. By around 8 weeks, if the sac is larger than 25mm and no embryo is seen, or if the sac is 16mm and no yolk or fetal pole is identified, the diagnosis of a blighted ovum may be made.

However, there are a few other situations where an ultrasound might show an empty sac in early pregnancy:

Wrong Dating: Pregnancy is typically dated from the first day of your last menstrual period. If these dates are off, or if you ovulated later than usual in your cycle, you could be less far along in the pregnancy than estimated.

In very early pregnancy (around 4 to 5 weeks), an ultrasound might show a gestational sac but no yet visible yolk sac or embryo. In this case, you would typically be asked to come back in a week or so for a follow-up scan.

Pseudo gestational Sac: In the case of an ectopic pregnancy, which is when a fertilized egg implants outside of the uterus (most often in a fallopian tube), a buildup of fluid in the uterus can sometimes appear as a gestational sac on an ultrasound, known as a pseudo gestational sac. However, this sac is empty, as the pregnancy is located elsewhere.

Molar Pregnancy: In a molar pregnancy, abnormal tissue grows in the uterus instead of an embryo. While not exactly an empty sac, a molar pregnancy can sometimes be mistaken for one on an early ultrasound, especially before the characteristic signs of a molar pregnancy become evident.

Missed or Early Miscarriage: Sometimes, an embryo starts to develop but then stops, and a miscarriage doesn’t immediately follow. This condition might appear as an empty sac on an ultrasound if the embryo was reabsorbed but the sac remains.

It’s important to consult with a healthcare provider if an empty gestational sac is found on an ultrasound.

They can provide guidance, arrange for further testing if needed, and discuss what the findings might mean for your pregnancy.

Management of Blighted Ovum and Empty Sac

There are several options for managing a blighted ovum. The body may naturally miscarry the pregnancy on its own. This process can be accompanied by symptoms like cramping and bleeding.

In some cases, medication can be used to prompt the body to miscarry. Another option is a medical procedure called dilation and curettage (D&C), where the contents of the uterus are removed.

The choice depends on the individual’s health, preferences, and the healthcare provider’s recommendations.

Pregnancy After a Blighted Ovum

A blighted ovum is generally a one-time occurrence, and having one does not necessarily increase the chances of having another.

Most individuals can expect a normal, healthy pregnancy following a blighted ovum. However, if recurrent miscarriages happen, it might be worth investigating for underlying causes.

In Conclusion

In summary, here are the key takeaways:

  • A blighted ovum, or an empty sac, often indicates an early pregnancy loss, generally due to chromosomal abnormalities.
  • Symptoms can mimic a typical pregnancy at first, but may fade over time or include spotting and cramping.
  • Diagnosis is made via ultrasound and sometimes confirmed with blood tests.
  • Treatment can range from natural miscarriage to medical intervention.
  • Having a blighted ovum does not necessarily increase the risk of having another, and many go on to have healthy pregnancies afterwards.

It’s essential to remember that a blighted ovum is no one’s fault. Coping with the loss of a pregnancy can be emotionally challenging, and it’s crucial to seek the support you need during this time.

Frequently Asked Questions about Empty Sac and Blighted Ovum


What are the chances of having a successful pregnancy after a blighted ovum?

Most people who experience a blighted ovum go on to have successful pregnancies in the future. A single blighted ovum does not increase the risk of future miscarriages or pregnancy complications.

However, if you have recurrent miscarriages, it may be worth discussing with your healthcare provider to investigate possible underlying causes.

How long does it take for the body to miscarry naturally after a blighted ovum diagnosis?

The timing can vary significantly from person to person. For some, the body might recognize the pregnancy is not viable within a few days or weeks of the diagnosis, leading to a natural miscarriage.

For others, it may take longer. If the process does not begin naturally or if the individual prefers, medical management options are available.

Can an empty sac still have a baby?

Usually, by 6 to 7 weeks of pregnancy, an ultrasound would show a fetal pole and yolk sac within the gestational sac.

If an ultrasound reveals an “empty” sac – meaning no embryo, with or without a yolk sac – by around 8 to 9 weeks, it’s likely a blighted ovum.

This diagnosis should be confirmed with sac measuring, a repeat ultrasound later or additional testing to ensure accuracy.

Does a blighted ovum mean I am infertile?

No, a blighted ovum does not indicate infertility. It is a common type of early pregnancy loss, often caused by chromosomal abnormalities in the fertilized egg. It typically does not predict or influence your ability to conceive in the future.

Can a blighted ovum be misdiagnosed?

While rare, there may be cases where a blighted ovum is misdiagnosed, often due to errors in estimating the gestational age. This is why healthcare providers usually confirm with a second ultrasound before making a definitive diagnosis.

Can I prevent a blighted ovum?

Because a blighted ovum is typically caused by chromosomal abnormalities in the fertilized egg, it is not usually preventable.

These abnormalities occur at random during fertilization and are not linked to anything the parents did or did not do.

However, maintaining a healthy lifestyle before and during pregnancy can contribute to overall reproductive health.

When can I try to get pregnant again after a blighted ovum?

This is a personal decision and can depend on physical recovery and emotional readiness.

Medically speaking, it is generally safe to try to conceive again after your hormone levels have returned to pre-pregnancy levels, and you’ve had at least one normal menstrual cycle.

However, it’s essential to discuss this with your healthcare provider for individual advice.

Further References

  1. American Pregnancy Association. (2020). Blighted Ovum. Retrieved from https://americanpregnancy.org/unplanned-pregnancy/blighted-ovum-709
  2. Mayo Clinic. (2021). Miscarriage. Retrieved from https://www.mayoclinic.org/diseases-conditions/pregnancy-loss-miscarriage/symptoms-causes/syc-20354298
  3. MedlinePlus. (2021). Blighted Ovum. Retrieved from https://medlineplus.gov/ency/article/001488.htm
  4. Johns Hopkins Medicine. (2021). Blighted Ovum (Anembryonic Pregnancy). Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/blighted-ovum-anembryonic-pregnancy
  5. Verywell Family. (2020). Understanding a Blighted Ovum Miscarriage. Retrieved from https://www.verywellfamily.com/what-is-a-blighted-ovum-2371721
  6. WebMD. (2021). What Is a Blighted Ovum? Retrieved from https://www.webmd.com/baby/blighted-ovum


This post is written and edited by Sandy who is a clinical pharmacist with over 20 years of experience specializing in pre-natal and post-natal care.