Receiving a diagnosis of any pregnancy complication can be an incredibly stressful and emotional experience.

If you’ve been told you have a scar ectopic pregnancy, you likely have many questions and concerns.

This is a rare but serious condition, and understanding what it means is the first step toward navigating your options.

This guide is designed to provide clear, expert information about caesarean scar ectopic pregnancy. We will walk you through what it is, why it happens, and how it’s diagnosed and treated.

Our goal is to empower you with the knowledge you need to have informed discussions with your healthcare team.

We will cover the key signs to watch for, the risk factors involved, the different treatment pathways available, and what this diagnosis might mean for your future fertility.

What is a Scar Ectopic Pregnancy?

A scar ectopic pregnancy is a rare type of ectopic pregnancy where the fertilised egg implants in the scar tissue from a previous caesarean section (C-section).

In a typical pregnancy, the embryo attaches to the wall of the uterus (endometrium). In this case, it implants into the fibrous scar within the uterine muscle.

Because the scar tissue is not designed to support a growing pregnancy, this condition is very serious.

The scar is not as strong or vascular as the normal uterine wall, which can lead to severe complications, including uterine rupture and major haemorrhage, if not diagnosed and treated early.

⇒Is a Scar Ectopic the Same as Other Ectopic Pregnancies?

No, a scar ectopic pregnancy is distinct from other types of ectopic pregnancies. Most ectopic pregnancies (over 95%) occur in the fallopian tube.

A scar ectopic pregnancy is a specific form of intrauterine pregnancy that has implanted in an abnormal location—the C-section scar—rather than the main uterine cavity.

This distinction is crucial because the diagnosis, risks, and treatment methods are different from those for a tubal pregnancy.

The primary cause is the presence of a C-section scar. It’s believed that a tiny defect or channel in the scar tissue from a previous caesarean delivery allows the fertilised egg to burrow into the myometrium (the muscular layer of the uterus) instead of the endometrium (the lining).

The exact mechanism is not fully understood, but the rising rate of C-sections worldwide has led to an increase in the incidence of this condition.

⇒Who is at Risk for a Scar Ectopic Pregnancy?

Any person who has had a prior caesarean section is at risk, but some factors may increase that risk.

Key Risk Factors:

• Previous C-section: This is the single biggest risk factor.
• Multiple C-sections: The risk may increase with the number of previous C-sections.
• Other Uterine Surgeries: Procedures like myomectomy (fibroid removal) that leave a scar on the uterus can also pose a risk.
• In Vitro Fertilisation (IVF): Some studies suggest that embryo transfers during IVF might slightly increase the risk of abnormal implantation, including in a scar.

The symptoms of a scar ectopic pregnancy can vary widely, and some people may not experience any at all in the early stages. This is why it is often detected during an early ultrasound scan.

When symptoms do occur, they can include:

• Painless Vaginal Bleeding: This is the most common symptom, often occurring after a period of amenorrhoea (missed periods).
• Mild to Moderate Abdominal Pain: Pain or cramping in the lower abdomen may be present but is often less severe than in tubal ectopic pregnancies.
• Positive Pregnancy Test with No Sac in Uterus: An ultrasound showing an empty uterine cavity but a positive pregnancy test is a red flag for an ectopic pregnancy of some kind.

It is important to seek immediate medical attention for any bleeding or pain during early pregnancy.

Early and accurate diagnosis is critical to prevent life-threatening complications. The primary diagnostic tool is a transvaginal ultrasound.

Diagnostic Steps:

1. hCG Blood Tests: A blood test to measure the pregnancy hormone, human chorionic gonadotropin (hCG), confirms pregnancy. Serial tests may be done to see how the levels are rising.
2. Transvaginal Ultrasound: This is the definitive test. A sonographer will look for specific criteria to confirm a scar ectopic pregnancy.
3. MRI: In some complex cases, a Magnetic Resonance Imaging (MRI) scan may be used to get a clearer view of the implantation site and its relationship to the bladder and surrounding structures.

Ultrasound Criteria for Diagnosis

Treatment aims to remove the pregnancy tissue and preserve the uterus if possible, while managing the significant risk of bleeding. The choice of treatment depends on the size of the pregnancy, hCG levels, clinical stability, and future fertility desires.

There is no single “best” treatment, and the decision is made on a case-by-case basis.

Treatment Methods:

1.Medical Management (Methotrexate):

How it works: An injection of methotrexate, a drug that stops cells from dividing, is used to end the pregnancy. It can be injected systemically (into a muscle) or locally (directly into the gestational sac guided by ultrasound).

Best for: Very early, stable cases with low hCG levels and no fetal heartbeat.

Follow-up: Requires close monitoring of hCG levels for weeks or months until they return to zero.

2.Surgical Management:

Uterine Artery Embolisation (UAE): Often done before surgery, this procedure blocks the blood vessels supplying the pregnancy to reduce bleeding risk.

Surgical Excision: The pregnancy tissue is removed, and the uterine defect is repaired. This can be done via hysteroscopy (through the cervix), laparoscopy (keyhole surgery), or laparotomy (open abdominal surgery).

Best for: More advanced pregnancies, high hCG levels, or when medical management fails. This approach often has a higher success rate and may offer a better outcome for future pregnancies by repairing the scar defect.

3.Hysterectomy:

What it is: Surgical removal of the uterus.

When it’s used: This is a last resort, typically reserved for cases with uncontrollable haemorrhage or severe uterine damage where the uterus cannot be saved.

Yes, it is possible to have a healthy pregnancy after treatment for a scar ectopic pregnancy. However, your future pregnancies will be considered high-risk.

The outcome often depends on the type of treatment you received. Surgical repair of the uterine scar defect may provide a stronger site for a future pregnancy compared to medical management alone.

You will require close monitoring from the very beginning of any subsequent pregnancy, including early ultrasounds to confirm the implantation site.

Your obstetrician will likely recommend a planned caesarean delivery for any future births.

• A scar ectopic pregnancy occurs when a fertilised egg implants in a C-section scar.
• It is a rare but serious condition with a high risk of uterine rupture and severe bleeding.
• The main symptom is often painless vaginal bleeding, but some people have no symptoms.
• Diagnosis is made via transvaginal ultrasound.
• Treatment options include medication (methotrexate) or surgery to remove the pregnancy tissue and repair the scar.
• Future pregnancies are possible but will be high-risk and require careful monitoring.

Q1: What is the success rate of treatment for scar ectopic pregnancy?
The success rate is high when the condition is diagnosed early. Surgical management, particularly with excision and repair of the scar, has a very high success rate (over 90%) in resolving the pregnancy and preserving the uterus. Medical management with methotrexate is less successful for more advanced cases but can be effective for very early diagnoses.

Q2: How long do I have to wait to get pregnant again after treatment?
The waiting period depends on your treatment. After methotrexate, you must wait at least 3-6 months before trying to conceive, as the drug can be harmful to a developing fetus. After surgical repair, your doctor will advise you on the optimal time for healing, which is typically at least 6-12 months.

Q3: Can a scar ectopic pregnancy be misdiagnosed?
Yes, it can sometimes be misdiagnosed as a miscarriage in progress or a low-lying intrauterine pregnancy. This is why diagnosis by an experienced sonographer who is specifically looking for the criteria of a scar ectopic is so important for an accurate and timely diagnosis.

Q4: Does having one C-section put me at high risk?
Having even one C-section creates the risk, but the risk remains very low overall. It is estimated to occur in about 1 in 2,000 pregnancies among people with a prior C-section. The risk does appear to increase with the number of C-sections you have had.

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• About Author

  Dr. Supriya Puranik

  Gynaecologist & IVF Specialist
  
  MMC -072514 (1993)

Dr. Supriya Puranik, a renowned gynaecologist and infertility expert, leads the IVF & Gynaecology department at Sahyadri Hospitals Momstory in Shivaji Nagar, Pune. She is committed to helping couples overcome infertility challenges.