Fertility treatments like in vitro fertilisation (IVF) have brought hope to countless people wishing to start or grow their family.

However, with the joy of these possibilities comes the awareness of potential risks and complications, including ectopic pregnancy.

With advancements in reproductive technology, both frozen and fresh embryo transfer methods are now widely used, but how do they differ in terms of safety, particularly when it comes to ectopic pregnancies?

This blog dives into the complexities of ectopic pregnancy rates with frozen versus fresh blastocyst transfers.

Through scientific insights, relatable examples, and medical expertise, we’ll unpack the details to help you make informed decisions.

Before comparing their respective ectopic pregnancy rates, it’s essential to understand what frozen and fresh transfers entail and how this crucial step in IVF works.

⇒What is a Fresh Blastocyst Transfer?

A blastocyst is a fertilised egg that has reached the 5-day development stage, containing around 100 cells. During a fresh transfer, the embryo is transferred straight into the uterus shortly after retrieval and fertilisation.

• How it works: After ovarian stimulation and egg collection, embryos are cultured and monitored until they reach the blastocyst stage. If the patient’s uterine lining (endometrium) is ready, the best-quality blastocyst is transferred into the uterus without freezing.
• Advantages: The process is quicker as it allows for immediate embryo implantation.
• Disadvantages: Hormonal imbalances caused by ovarian stimulation may impact the success rate.

⇒What is a Frozen Blastocyst Transfer?

A frozen embryo transfer (FET) involves freezing a blastocyst for later use. When the patient is ready, the thawed embryo is transferred into the optimally prepared uterus.

• How it works: After fertilisation, the embryos are cultured to the blastocyst stage, then frozen using advanced cryopreservation techniques.
• Advantages: The uterine lining can be better prepared in a natural or medicated cycle, improving chances of implantation.
• Disadvantages: While freezing and thawing processes have improved significantly, some embryos may still not survive thawing.

Ectopic pregnancies occur when the fertilised egg implants outside the uterus, most commonly in the fallopian tube.

This is a potentially serious condition that requires immediate medical attention. But why would embryo transfer methods influence this risk?

According to Dr Supriya Puranik, a fertility specialist in pune with years of experience,

“The risk of ectopic pregnancy is generally low with IVF, but certain factors such as a patient’s medical history, fallopian tube damage, and the embryo transfer method can play a role in increasing or reducing this risk.”

⇒Fresh Blastocyst Transfer and Ectopic Pregnancy

During a fresh transfer, ovarian stimulation may alter the uterine environment, potentially creating less favourable conditions for the embryo to implant correctly.

Research suggests that hormonal changes induced by the fresh transfer cycle could impact how the embryo moves within the uterus, leading to a slightly elevated risk of ectopic pregnancy compared with frozen transfers.

⇒Frozen Blastocyst Transfer (FET) and Ectopic Pregnancy

Frozen transfers are performed in a carefully prepared uterine environment, often free from the hormonal fluctuations caused by ovarian stimulation. This controlled approach has been associated with a lower likelihood of ectopic pregnancies.

⇒What Do Studies Show?

Recent studies comparing ectopic pregnancy rates with frozen versus fresh transfers indicate a slight advantage for frozen transfers.

• A Large-Scale Analysis published in scientific journals observed that FET cycles have a 1.3%-1.5% ectopic pregnancy rate compared to 1.5%-2% with fresh transfers. While the overall numbers are small, the difference is statistically notable.
• Another Study highlighted that the uterine preparation for FET creates a more synchronised endometrial lining, reducing the chances of abnormal implantation.

It’s worth noting that while the rates are different, the risk remains low in both methods.

Although the type of transfer plays a role, other factors significantly impact ectopic pregnancy risk, including individual patient circumstances and medical history. Here are some known risk factors to keep in mind:

1. Fallopian Tube Damage: Scarring or blockage from infections, previous ectopic pregnancies, or surgeries can increase the odds of abnormal implantation.
2. Hormonal Imbalances: Hormones essential for pregnancy might affect how the embryo interacts with the uterus in fresh transfers.
3. Age: Women of advanced maternal age (35+) may have a slightly increased risk.
4. Uterine Abnormalities: Structural issues like fibroids or scar tissue can impact where the embryo implants.
5. Multiple Embryo Transfer: Transferring multiple embryos raises the chances of one implanting outside the uterus.

Early diagnosis is critical for managing ectopic pregnancies safely. Because IVF patients are monitored closely, they often receive earlier diagnoses compared with natural pregnancies.

⇒Common Diagnostic Methods:

• Blood Tests: Measuring hCG levels over time. Slow-rising hCG could be a sign of an ectopic pregnancy.
• Transvaginal Ultrasound: Visualises where the embryo has implanted, confirming its location in or outside the uterus.
• Pelvic Exam: Performed by your doctor to detect any tenderness or abnormalities.

While there’s no guaranteed way to eliminate the risk of ectopic pregnancy, there are steps you can take to minimise it, particularly if you’re undergoing IVF.

⇒Expert-Backed Tips

1. Discuss Risk Factors with Your Doctor: Be upfront about past surgeries, infections, or reproductive health concerns so a plan can be tailored to your needs.
2. Freeze Embryos for Transfer: If recommended by your ectopic pregnancy specialist, frozen transfers may provide a slight edge in lowering ectopic pregnancy risk.
3. Choose Single Embryo Transfer (SET): Transferring just one embryo at a time has been shown to reduce the risk of ectopic pregnancy.
4. Quit Smoking: If you smoke, stopping can significantly improve your overall reproductive health.
5. Follow Your Treatment Plan Closely: Adhere to medical advice before, during, and after embryo transfer to optimise conditions for implantation.

⇒Dr. Puranik’s Insights

Dr Supriya Puranik shares her perspective,

“Many patients feel anxious about the possibility of complications like ectopic pregnancy.

While we can’t eliminate every risk, choosing approaches such as frozen transfers and maintaining open communication can significantly improve outcomes.

Knowledge and preparation empower parents-to-be on their IVF journey.”

IVF is a delicate process with many considerations, and while ectopic pregnancies are rare, understanding the slight differences between frozen and fresh transfers can help you make informed decisions.

Research continues to show that frozen transfers, due to their controlled nature, are associated with a marginally lower risk of ectopic pregnancy.

However, your overall medical history and risk factors play a much larger role in determining outcomes.

Whether you’re considering IVF for the first time or preparing for another cycle, don’t hesitate to discuss any questions or concerns with your healthcare provider.

Together, you can develop a personalised treatment plan to maximise success while minimising risks.

Your IVF journey is unique, and with the right guidance and care, it can lead to the family you’ve been dreaming of.

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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.