Why Are Eggs Retrieved Twice in One Menstrual Cycle? Understanding Dual Stimulation in IVF

Introduction

A 2025 systematic review and meta-analysis estimated that 8% of women of reproductive age in India experience infertility. If you are looking for fertility treatment, you may have come across dual stimulation (DuoStim) in IVF, where doctors perform egg retrieval twice in one cycle. This can naturally raise some questions about why two eggs are needed, how safe the procedure is, and whether it’ll improve your chances of getting pregnant. DuoStim is a carefully planned treatment option, and it can help collect more eggs in less time, especially for people with low ovarian reserves and an urgent need for fertility preservation.

In this blog, we’ll discuss how DuoStim works, who can benefit from it, risk factors, and more, so you can discuss your treatment options with more confidence.

What Is DuoStim in IVF?

DuoStim is an advanced IVF procedure in which you undergo two separate rounds of ovarian stimulation and two egg retrievals within a single menstrual cycle. This IVF treatment helps maximise the number of eggs retrieved in a much shorter timeframe by capitalising on the ovaries’ natural multiple follicular waves.

Why Are Eggs Retrieved Twice in One Menstrual Cycle?

Eggs are retrieved twice in a single menstrual cycle to collect a higher number of mature eggs and build viable embryos in a shorter timeframe. There are other reasons why doctors may recommend retrieving eggs twice in a single menstrual cycle:

Understanding Multiple Follicular Waves

A 2020 study published in Fertility and Sterility shows that approximately two-thirds of women develop two follicle waves during one menstrual cycle, while the rest experience three. Doctors stimulate the second wave after the first egg retrieval in dual ovarian stimulation. This makes the second retrieval of eggs possible within the same cycle.

Maximising Egg Collection in a Short Time

Collecting more eggs without waiting for another cycle is the main aim of DuoStim. This can be especially helpful for women who only produce a few eggs with each stimulation, increasing the number of eggs and embryos available for future treatment.

Reducing Delays Between IVF Cycles

DuoStim shortens the time it takes to collect eggs by completing two stimulation phases in one menstrual cycle. Though it should be used selectively, not routinely, it has consistently improved live birth rates compared to standard IVF procedures.

How Does DuoStim Work?

While the treatment plan is personalised based on individual circumstances, it generally follows the steps below:

Initial Fertility Assessment

Your fertility specialist will first perform blood tests, including anti-Müllerian hormone (AMH), review your medical history and previous response to conventional IVF, and perform an ultrasound to assess your ovarian reserves and determine whether DuoStim is suitable for you.

First Ovarian Stimulation (Follicular Phase)

Early in the menstrual cycle, you’ll be given hormone injections for 8-12 days to stimulate multiple follicles. Doctors will perform blood tests and ultrasound scans to monitor follicle growth until eggs are ready for retrieval.

First Egg Retrieval

A thin needle guided by ultrasound is used to perform the first egg retrieval, with the person under anaesthesia or sedation. The collected eggs are then sent to the laboratory for assessment.

Second Ovarian Stimulation (Luteal Phase)

A second hormone stimulation is performed a few days later during the luteal phase. Once again, doctors monitor until the second group of follicles matures.

Second Egg Retrieval

The doctors use the same procedure to retrieve the eggs twice in the same cycle once the follicles are ready.

Fertilisation and Embryo Development

IVF or intracytoplasmic sperm injection (ICSI) is used to fertilise retrieved eggs. Doctors monitor the resulting embryos as they develop in the laboratory.

Embryo Freezing and Future Transfer

Most DuoStim cycles use a freeze-all approach. The embryos are frozen and transferred in a later menstrual cycle, when the uterus is better prepared for implantation.

Who May Benefit from DuoStim?

Fertility specialists don’t routinely recommend DuoStim to everyone undergoing IVF. It is generally considered when it’s especially important to collect eggs quickly or when conventional stimulation may not produce enough eggs in a single cycle. They will assess your age, hormone levels, ovarian reserves, and previous response to IVF before deciding whether this approach is right for you.

You can be a candidate if you have one or more of the following:

• Poor ovarian response, meaning you produced very few eggs or had poor blastocyst yield during previous standard IVF. Poor ovarian response affects almost 9% to 24% of IVF cycles and accounts for more than half of IVF cycle cancellations, according to a 2026 study published in the International Journal of Gynecology & Obstetrics.
• Diminished ovarian reserves due to low AMH levels, high follicle-stimulating hormone (FSH) levels or a low antral follicle count (AFC).
• Advanced maternal age (between 38 and 45 years of age) and want to avoid age-related delays between cycles.
• Plan to test embryos for genetic conditions before transfer. Doctors may recommend collecting more embryos to increase the chances of finding one suitable embryo to transfer.
• Want urgent fertility preservation while preparing for chemotherapy, radiotherapy, and other treatments that may affect ovarian function, so you don’t have time to wait for another menstrual cycle.

Benefits of DuoStim in IVF

Here are the key benefits of DuoStim:

• More eggs can be collected in less time.
• DuoStim increases the number of embryos available for future transfer, which also makes it easier to find healthy, chromosomally normal (euploid) embryos when using preimplantation genetic testing (PGT).
• It reduces the waiting time between menstrual cycles for starting another ovarian stimulation.
• Completing egg collection sooner can be useful in time-sensitive situations.
• Eggs retrieved during the luteal phase generally have similar developmental potential to those collected during the follicular phase.

Are There Any Limitations of DuoStim?

DuoStim has its limitations, and understanding them can help you set realistic expectations before you begin the treatment. Here are some considerations:

• There can be no fresh embryo transfer. Since two stimulation cycles happen back-to-back in one month, the uterine lining (endometrium) becomes out of sync with the ovaries, and it cannot safely receive a fresh embryo. This means all embryos must be frozen (cryopreserved).
• Doctors still aren’t sure whether the second wave of eggs during the luteal phase grows because of the second round of stimulation or simply as an effect carried over from the first one.
• The second phase of DuoStim often requires higher doses of medication. You may need extra hormone support to prevent poor egg quality, as natural progesterone produced after the first ovulation can suppress luteinizing hormone (LH).
• Undergoing two stimulations and egg retrievals, along with intensive monitoring and medications in a single month, can not only increase the upfront cost but can also have a physical toll on the person.
• Though DuoStim may increase the number of eggs retrieved in a single cycle, it does not guarantee improvements in pregnancy rates.

DuoStim vs Conventional IVF

While both standard IVF and DuoStim aim to retrieve healthy eggs and create embryos, they differ in how ovarian stimulation is planned.

Conclusion

If your doctor recommends egg retrieval twice in one cycle, it is because collecting more eggs within a shorter timeframe may increase your chances of pregnancy. Doctors often recommend DuoStim for women with poor ovarian reserves, advanced maternal age, urgent fertility preservation needs, among other reasons. Though this treatment option can reduce the time needed to collect eggs and embryos, it’s not suitable for everyone. The most appropriate IVF procedure for you will depend on your age, fertility profile, and an overall assessment of your medical conditions.