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Why Ultrasounds May Cause Misdiagnosed Miscarriages

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Are you in your first trimester? Have you recently had an ultrasound? Has your doctor indicated that you may miscarriage because of the results of that ultrasound?

Hi. I'm Kay. I have been writing about misdiagnosed miscarriages on the web before they were even acknowledged on the web or by the medical community. As we collect more and more stories on the Misdiagnosed Miscarriage website, one theme remains clear: If you have had a misdiagnosed miscarriage, very likely it is due to your ultrasound results and your doctor diagnosing you too early based on those results.

Let's learn more about why ultrasounds alone should not, in many cases, be used to definitively diagnose a miscarriage.

DISCLAIMER: I am not a medical professional. The information I share is meant to supplement the information given you by your doctor. If you feel your doctor is not doing enough for you or not willing to listen to your concerns, I strongly encourage you to take what you've learned here and get a second opinion.

Let's Start with the New Research and Advice Being Given

by the medical community.

Until the last few years, the idea of a misdiagnosed miscarriage was denied by the vast majority of the medical community. Our site, The Misdiagnosed Miscarriage, has been working tirelessly to collect stories to show them that, yes indeed, a miscarriage may be misdiagnosed and it happens too frequently. The medical community is now just beginning to take note.

Let's look at what they are saying:

The American Preganancy Association

First from the American Pregnancy Association's website:

"If an ultrasound is done at 6 to 7 weeks and a heartbeat is not detected, does that mean there is a problem? No it does not mean there is a problem. The heartbeat may not be detected for reasons that include: tipped uterus, larger abdomen, or inaccurate dating with last menstrual period."

Here they are acknowledging that if your baby is not seen by seven weeks, it may just be due to a tilted uterus. This is huge because we have been trying to get them to acknowledge this for years and it has been fiercely denied by many.

Up to 1/3 of women have a tilted uterus plus, the the uterus can change position from pregnancy to pregnancy so doctors rarely mention whether yours is tilted or not. If you don't know, ask during your next exam or ultrasound.


WebMD recently published the article "Does ultrasound sometimes misdiagnose miscarriage?"

"The fourth study explored the accuracy of ultrasound measurements when repeated by the same doctor, and also by a different doctor. Although the repeated measurements were largely similar, there was enough variation to raise concern - particularly when the measurements were close to the cut-offs used in guidelines to diagnose miscarriage. For example, if one doctor measured the sac as being 20 millimetres in diameter, the range for the other doctor’s measurement varied from 16.8 to 24.5 millimetres."

This shows that human error in reading ultrasounds plays a large roll. I have talked to women who had two different ultrasounds the same day by two different techs and gotten very different measurements. This is worrisome because a difference of only a few millimeters can cause a doctor to diagnose you with a miscarriage.

In fact, if you take a look at my blog post And, Even More on the Unreliability of Ultrasound Measurements During the First Trimester , you can read the story of woman who had the exact same ultrasound photo examined by another ultrasound tech and that tech found the first measurements were quite wrong and her pregnancy was well within the normal range.


Journal of Fertility and Sterility

This next blurb comes out of a leading journal for physicians treating and investigation issues related to infertility and human reproductive disorders. When is a pregnancy nonviable and what criteria should be used to define miscarriage? Here is the abstract of that study:

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"When is a pregnancy nonviable and what criteria should be used to define miscarriage?


In 2011, the first systematic review of the evidence behind the diagnostic criteria for miscarriage was published. It states, 'findings were limited by the small number and poor quality of the studies,' and concluded that further studies were, 'urgently required before setting future standards for the accurate diagnosis of early embryonic demise.' This implies that data used to define criteria to diagnose miscarriage are unreliable. The 2011 Irish Health Service executive review into miscarriage misdiagnosis highlighted this issue. In parallel to these publications a multicenter prospective study was published examining cut-off values for mean sac diameter (MSD) and embryo size to define miscarriage. The authors also published evidence on expected findings when ultrasonography is repeated at an interval. This led to guidance on diagnostic criteria for miscarriage in the UK changing. These new criteria state miscarriage be considered only when: an empty gestation sac has an MSD of ≥ 25 mm (with no obvious yolk sac), or embryonic crown rump length ≥ 7 mm (the latter without evidence of fetal heart activity). If in doubt, repeating scans at an interval is emphasized. It is axiomatic that decisions about embryonic viability must not be open to doubt. So it is surprising how little evidence exists to support previous guidance. Any clinician working in this area knows of women being wrongly informed that their pregnancy has failed. This cannot be acceptable and guidance in this area must be 'failsafe.'"

First and foremost, they are pointing out there have been a serious lack of studies on what it takes to really diagnose a miscarriage. Secondly, they are pointing out that empty-looking gestational sacs are causing doctors to diagnose a miscarriage too early. Unless your gestational sac is at least 25mm, they should not be diagnosing a blighted ovum.

The New England Journal of Medicine

In 2013, The New England Journal of Medicine published Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester

This little snippet stood out:

"Furthermore, considerable evidence suggests that mistakes

such as these are far from rare. Malpractice lawsuits related to this type of error

constitute 'a rapidly increasing source of medical liability actions,'and there are

online support groups for women erroneously treated in this manner.'"

For ten years now, we've been collecting stories of women who have been misdiagnosed with miscarriage online. These stories are making a difference. The medical community is taking note.

When Should a Miscarriage Be Diagnosed?

Let me start by saying, this not not apply if they suspect an ectopic pregnancy. This is for women whose doctors have found the gestational sac and deemed the pregnancy to not be ectopic.

- According to the American Pregnancy Association:

"After 10 weeks, the miscarriage is more likely to be incomplete, requiring a D&C procedure to be performed. Choosing whether to miscarry naturally (called expectant management) or to have a D&C procedure is often a personal choice, best decided after talking with your health care provider...For most first trimester miscarriages, expectant management should be a viable option."

If you do not have serious complications, waiting until ten weeks would likely rule out 95% (or more) of misdiagnosed miscarriages. Yes, we have seen some misdiagnosed miscarriages after ten weeks but they are certainly rare. Misdiagnosed miscarriages before ten weeks are not rare. If you choose to wait out a diagnosis, stay closely monitored and be seen right away if there are any complications. Also, if you are anemic, be aware that that a natural miscarriage may be too much for your body. I've talked to women who have ended up in the ER due to the intense bleeding.

Keeping in mind human error is common in reading ultrasounds, you won't want to have your pregnancy diagnosed a miscarriage simply because the gestational sac is less than 25mm. My own gestational sac was 21.5mm and still appeared empty. A week later, at 28.5mm, we found my baby. If the sac is not growing from week to week though, you likely have your answer but, again, keep in mind, while it is not growing for one tech, another tech may find that it is!

The same goes for yolk sac measurements. We've had women scared because the yolk sacs appeared too large only to find they were actually in normal range.

As for hCG levels, we at the Misdiagnosed Miscarriage website believe they are a very poor indicator of miscarriage unless they are dropping by very large numbers suddenly. After the gestational sac is viewed, they and rise, plateau or even drop and still be normal.

If there are no serious complications and women wait until ten weeks to have their pregnancy diagnosed as a miscarriage, they can have their pregnancies ended and not doubt they ended a viable pregnancy.

What Would You Do?

Are you going through a miscarriage scare? If so, find support on the Misdiagnosed Miscarriage website. I'd love to hear from you!

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