An ectopic pregnancy happens when a fertilised egg implants outside the womb, most commonly in one of the fallopian tubes. It can sometimes be misdiagnosed because many of the early symptoms, (including abdominal pain and vaginal bleeding), overlap with other conditions and problems in early pregnancy.

A delayed or misdiagnosed ectopic pregnancy can have serious consequences. If the pregnancy continues to grow within the fallopian tube, the tube may rupture, potentially causing life-threatening internal bleeding and requiring emergency surgery.

Because an ectopic pregnancy can be difficult to diagnose in its early stages, a failure to do so does not necessarily mean that the care is “negligent” in the legal sense. The key question is whether the GP, doctor, nurse or hospital recognised the possibility of an ectopic pregnancy, carried out appropriate investigations and arranged suitable monitoring and follow-up where the diagnosis remained unclear.

In this guide, our clinical negligence experts explain how an ectopic pregnancy can often be mistaken for other conditions, the steps doctors should take to investigate their concerns and when a misdiagnosis or delayed diagnosis may provide grounds for a medical negligence claim.

What Is an Ectopic Pregnancy?

An ectopic pregnancy occurs when a fertilised egg implants outside the womb, usually in a fallopian tube. Around one in every 90 pregnancies in the UK is ectopic, equivalent to approximately 11,000 pregnancies each year. Symptoms most commonly develop between weeks four and 12, although an ectopic pregnancy can sometimes be identified before symptoms develop.

A pregnancy cannot develop normally within the fallopian tube. As it grows, there is a risk that the tube can rupture and cause internal bleeding, which requires urgent medical treatment.

Treatment depends on factors including the person’s symptoms, scan findings and hCG (human chorionic gonadotropin) levels. The main treatment options are expectant management, where the pregnancy is closely monitored to see whether it resolves without further intervention, medical management with methotrexate (which is an injection to safely end an early, unruptured ectopic pregnancy); or surgery. If the fallopian tube has already ruptured, emergency surgery is required.

What Are the Symptoms of an Ectopic Pregnancy?

The symptoms of an ectopic pregnancy can vary, and some people may not notice anything unusual at first. When symptoms do develop, they often appear between weeks four and 12 of pregnancy.

Symptoms may include:

• Pain low down on one side of the abdomen or pelvis
• Vaginal bleeding or a brown watery discharge
• Shoulder-tip pain
• Pain or discomfort when going to the toilet
• Dizziness or fainting
• Sudden, severe abdominal pain

These symptoms can overlap with other problems in early pregnancy, such as miscarriage, which is one reason an ectopic pregnancy may initially be misdiagnosed.

A positive pregnancy test combined with persistent one-sided pelvic pain or unusual vaginal bleeding should be assessed promptly. Severe abdominal pain, shoulder-tip pain, dizziness or fainting can indicate internal bleeding and require urgent medical attention.

Why Can an Ectopic Pregnancy Be Difficult to Diagnose?

An ectopic pregnancy can be difficult to diagnose because the early symptoms are not always distinctive. Abdominal pain, bleeding, nausea and changes in pregnancy symptoms can all occur for other reasons.

In very early pregnancy, an ultrasound scan may also be inconclusive. If a pregnancy is too small to be seen clearly, doctors may not immediately be able to confirm whether it is developing inside or outside the womb.

Other factors that can make diagnosis more difficult include:

• Uncertain pregnancy dates
• Mild or fluctuating symptoms
• A very early gestational age
• hCG levels that need repeat testing before a pattern becomes clear

This is why the diagnostic process may involve more than one appointment. Doctors may need to assess the person’s symptoms with a transvaginal ultrasound and repeated blood tests measuring hCG levels.

The key issue is not necessarily whether the ectopic pregnancy was diagnosed at the first appointment, but whether the diagnostic pathway was followed including any safety netting advice which would, on balance, have led to the avoidance of injury.

What Can an Ectopic Pregnancy Be Misdiagnosed As?

Because the symptoms overlap with several other conditions, a misdiagnosed ectopic pregnancy may initially be attributed to another explanation.

Miscarriage

Miscarriage is one of the most common conditions that can be confused with an ectopic pregnancy because both can cause vaginal bleeding and abdominal or pelvic pain.

A positive pregnancy test followed by bleeding does not, by itself, establish that a miscarriage has occurred. Where the location of the pregnancy has not been confirmed, doctors may need to continue monitoring until they can establish whether the pregnancy is developing in the womb, has miscarried or is ectopic.

Problems can arise where symptoms are treated as a completed miscarriage without appropriate follow-up, particularly if the person continues to experience pain, bleeding or abnormal hCG results.

Ovarian cysts

An ovarian cyst can cause one-sided pelvic pain and may sometimes appear alongside an early pregnancy.

Ultrasound usually helps doctors distinguish between an ovarian cyst and an ectopic pregnancy, but very early findings may not always be clear. Where there is uncertainty, symptoms and blood test results may need to be monitored rather than relying on one scan alone.

Gastrointestinal problems

Abdominal pain, nausea, vomiting and changes in bowel habits can sometimes lead to an ectopic pregnancy being mistaken for a gastrointestinal problem.

Doctors should consider pregnancy-related causes alongside other possible explanations, particularly if there is a missed period, positive pregnancy test or vaginal bleeding.

Normal early pregnancy pain

Mild cramping can occur during a normal pregnancy. However, persistent or worsening one-sided pain, especially when combined with bleeding or other warning signs, may require further investigation.

Symptoms should not be dismissed as a normal part of pregnancy where the overall clinical picture suggests that an ectopic pregnancy needs to be ruled out.

Other gynaecological conditions

Pelvic inflammatory disease, a urinary tract infection and other gynaecological conditions can also produce abdominal or pelvic pain.

The role of the doctor is to consider the full range of differential diagnoses and to rule those out in order to reach a definitive position.

How Should Doctors Investigate a Suspected Ectopic Pregnancy?

Doctors may need to use several sources of information to diagnose an ectopic pregnancy accurately.

The assessment can include:

• A detailed history of the person’s symptoms
• A pregnancy test
• A transvaginal ultrasound
• Blood tests measuring human chorionic gonadotropin (hCG)
• Repeat assessment where the diagnosis remains uncertain

A single test may not provide a clear answer. In some cases, hCG levels are measured again after around 48 hours to help doctors understand how the pregnancy is progressing. Ultrasound findings should be considered alongside these results and the person’s symptoms.

Where the diagnosis remains unclear, further investigations may be needed. In some cases, diagnostic keyhole surgery may be considered.

Find out more about screening negligence cases here.

What Is a Pregnancy of Unknown Location?

A pregnancy of unknown location is the term used when a pregnancy test is positive but an ultrasound scan does not show a pregnancy either inside or outside the womb.

This does not automatically mean that the pregnancy has miscarried. It may be too early to see the pregnancy on ultrasound, or the pregnancy may be ectopic.

For this reason, a pregnancy of unknown location should usually be monitored until doctors can establish what has happened. This may involve repeat blood tests, another ultrasound scan and continued assessment of symptoms.

If symptoms worsen while this monitoring is taking place, the person should be reassessed promptly.

Can an Ultrasound Miss an Ectopic Pregnancy?

An ectopic pregnancy may not always be visible on the first ultrasound scan, particularly very early in pregnancy.

The scan may be inconclusive because:

• The pregnancy is too small to identify
• The exact location is difficult to see
• There is not yet enough information to distinguish between an early pregnancy in the womb and an ectopic pregnancy
• Other structures, such as an ovarian cyst, can complicate the appearance

This is why doctors should not rely on an inconclusive scan alone to rule out an ectopic pregnancy.

If there is still concern, they may need to arrange repeat imaging, monitor hCG levels and give clear advice about symptoms that require urgent attention.

Can Blood Tests Rule Out an Ectopic Pregnancy?

No single hCG blood test can reliably rule out an ectopic pregnancy.

Doctors may compare hCG levels over time because the pattern can help indicate whether a pregnancy is developing as expected. However, hCG results should not be interpreted in isolation.

A person can still have an ectopic pregnancy where hormone levels do not follow a typical pattern. Symptoms, ultrasound findings and the overall clinical picture therefore remain important.

What Should Happen If an Ectopic Pregnancy Cannot Be Ruled Out?

Where doctors cannot confirm the location of the pregnancy, appropriate follow-up is important.

Depending on the circumstances, this may include:

• Referral to an early pregnancy assessment service
• Repeat hCG blood tests
• Repeat transvaginal ultrasound
• Continued monitoring of pain and bleeding
• Clear information about warning signs
• Instructions about where to seek urgent care if symptoms worsen

The aim is to continue assessment until the location and outcome of the pregnancy are established.

This safety-netting is particularly important because symptoms can change quickly. Severe or worsening abdominal pain, dizziness, fainting or shoulder-tip pain may indicate internal bleeding and requires urgent medical attention.

What Can Happen If an Ectopic Pregnancy Is Not Diagnosed?

The effects of a misdiagnosed ectopic pregnancy depend on how long diagnosis and treatment are delayed.

If the ectopic pregnancy continues growing within the fallopian tube, the tube may rupture and cause internal bleeding. This is a medical emergency.

A delayed diagnosis may result in:

• More severe abdominal pain
• Significant internal bleeding
• Emergency surgery
• Removal of the affected fallopian tube
• A longer recovery
• Time away from work
• A recognised psychological injury
• Effects on fertility in some circumstances

These outcomes are not inevitable. Some ectopic pregnancies are diagnosed early enough to be monitored or treated medically without surgery.

JMW has supported clients ion numerous cases, where an ectopic  pregnancy has not been promptly diagnosed and as a result they have suffered avoidable harm, . In several cases, the delay meant the fallopian tube had already ruptured by the time the correct diagnosis was made.

Can an Ectopic Pregnancy Resolve Without Surgery?

Sometimes. Depending on the person’s symptoms, hCG levels and scan findings, an ectopic pregnancy may be managed through expectant management, where doctors monitor the pregnancy closely to see whether it resolves naturally.

Other people may be treated with medication, while some require surgery.

The appropriate treatment depends on the individual circumstances. A ruptured ectopic pregnancy generally requires emergency surgery.

When Could a Misdiagnosed Ectopic Pregnancy Amount to Medical Negligence?

A misdiagnosed ectopic pregnancy does not automatically mean medical negligence occurred. Early diagnosis can sometimes be difficult, particularly where symptoms and test results are inconclusive.

There may be grounds to investigate an ectopic pregnancy negligence claim where, for example:

• A GP or hospital doctor failed to consider ectopic pregnancy despite relevant symptoms
• Abdominal pain and vaginal bleeding were repeatedly attributed to miscarriage without adequate investigation
• A positive pregnancy test combined with one-sided pain was not acted on
• Ultrasound findings were misinterpreted
• Concerning hCG results were not followed up
• A pregnancy of unknown location was not monitored appropriately
• Repeat scans or blood tests were not arranged when required
• Worsening symptoms were dismissed or not escalated
• The person was discharged without appropriate safety-netting

The legal question is whether the care fell below the reasonable standard expected and whether that failure caused additional avoidable harm.