What Happens During an IVF Treatment Cycle?

In-vitro fertilisation (IVF) is a form of assisted reproductive treatment in which eggs and sperm are brought together in a laboratory to create embryos before an embryo is transferred into the uterus.

For patients considering IVF, the process can initially seem complicated because it involves several stages, including medication, monitoring, egg retrieval, fertilisation, embryo development and embryo transfer.

A typical IVF cycle takes place over several weeks, although the exact timeline varies depending on the treatment protocol, menstrual cycle, ovarian response and whether a fresh or frozen embryo transfer is planned.

What Is IVF?

IVF involves fertilising an egg with sperm outside the body in a laboratory.

The basic process involves:

Preparing the ovaries
Stimulating the development of multiple follicles
Monitoring the ovarian response
Retrieving the eggs
Fertilising the eggs with sperm
Growing the resulting embryos
Transferring an embryo into the uterus
Testing for pregnancy

The aim is to create an embryo that can subsequently implant in the uterus and develop into a pregnancy.

Not every egg retrieved will necessarily be fertilised, and not every fertilised egg will develop into an embryo suitable for transfer or freezing.

How Long Does an IVF Cycle Take?

The duration varies between patients and treatment protocols.

The ovarian stimulation phase may take approximately two to four weeks, depending on the protocol and individual response. Egg retrieval generally takes place around 36 hours after the final maturation or trigger injection.

Following retrieval, embryos are usually cultured for several days before transfer or cryopreservation.

A pregnancy blood test is then performed after the embryo transfer at a time determined by the fertility centre.

Some patients will have a fresh embryo transfer, while others may have all suitable embryos frozen and undergo a frozen embryo transfer during a later cycle.

The overall treatment timeline can therefore differ considerably between patients.

What Happens Before an IVF Cycle Begins?

IVF usually begins with an assessment and treatment-planning stage rather than immediately starting injections.

The fertility team may review:

Medical history
Previous fertility treatment
Menstrual cycle
Ovarian reserve
Pelvic ultrasound findings
Semen analysis
Previous pregnancy history
Existing medical conditions
Medications and supplements

Additional investigations may be performed depending on the individual’s circumstances.

Counselling and Consent

Patients should receive information about:

The IVF process
Medication
Egg retrieval
Fertilisation
Embryo transfer
Embryo freezing
Potential risks
Possible outcomes

Consent is also required for relevant procedures and the handling or cryopreservation of embryos.

Some patients may also benefit from counselling to prepare for the emotional and physical demands of fertility treatment.

Step 1: Ovarian Stimulation

During a natural menstrual cycle, usually one dominant follicle develops and releases an egg.

During IVF, medication is used to encourage the ovaries to develop multiple follicles so that several eggs may be available for retrieval.

The medication typically involves injectable hormones called gonadotropins.

Depending on the IVF protocol, other medication may be used to prevent premature ovulation.

Why Are Multiple Eggs Needed?

Not every egg retrieved will necessarily:

Be mature
Fertilise normally
Develop into an embryo
Be suitable for transfer

Having several eggs available therefore provides more opportunities for fertilisation and embryo development within a treatment cycle.

The aim is not simply to produce as many eggs as possible. The stimulation protocol is adjusted according to the patient’s age, ovarian reserve, previous treatment and expected response.

Step 2: Monitoring the Ovaries

Ovarian stimulation requires monitoring.

The fertility team may use:

Transvaginal ultrasound
Blood tests
Hormone measurements where appropriate

Ultrasound allows the doctor to assess:

Number of developing follicles
Follicle size
Ovarian response

Blood tests may provide additional information about hormone levels.

The medication dose may be adjusted depending on how the ovaries respond.

Why Is Monitoring Important?

Monitoring helps the fertility team determine when the follicles have developed sufficiently for egg retrieval.

It also helps identify an excessive response to stimulation, which can increase the risk of ovarian hyperstimulation syndrome (OHSS).

The stimulation protocol can therefore be adjusted when necessary.

Step 3: The Trigger Injection

Once the follicles have reached an appropriate stage of development, a final injection is given to trigger final egg maturation.

The medication used for this step depends on the IVF protocol.

The timing is particularly important because egg retrieval is scheduled at a specific interval after the trigger injection.

In many protocols, egg retrieval takes place approximately 36 hours after the trigger.

Patients need to follow the timing instructions carefully because taking the trigger medication too early or too late can affect the treatment schedule.

Step 4: Egg Retrieval

Egg retrieval, also called oocyte retrieval or oocyte pick-up, is the procedure used to collect eggs from the ovaries.

It is generally performed using:

Transvaginal ultrasound guidance
A specialised needle
Sedation or anaesthesia appropriate to the procedure

The needle passes through the vaginal wall towards the ovaries, allowing the follicles to be aspirated and their contents collected.

The embryology laboratory then identifies the eggs within the collected fluid.

How Long Does Egg Retrieval Take?

The procedure itself is generally relatively short, although the total time spent at the fertility centre will be longer because of preparation, sedation and recovery.

Patients are usually monitored for a period after the procedure before going home.

Is Egg Retrieval Painful?

Patients may experience:

Pelvic discomfort
Cramping
Bloating
Mild vaginal bleeding

The level of discomfort varies.

Medication and sedation are used to make the procedure more comfortable.

What Happens If Fewer Eggs Are Retrieved Than Expected?

The number of eggs retrieved can vary significantly between patients.

It depends on factors such as:

Age
Ovarian reserve
Response to stimulation
Previous ovarian surgery
Underlying medical conditions

The number of follicles seen on ultrasound does not necessarily equal the number of eggs retrieved.

Not every follicle contains a mature egg, and not every retrieved egg will be mature enough for fertilisation.

A lower number of eggs does not automatically mean that the IVF cycle cannot result in pregnancy.

Step 5: Sperm Collection and Preparation

Around the time of egg retrieval, a sperm sample is usually collected from the male partner.

The laboratory then processes the sample to identify sperm with suitable characteristics for fertilisation.

The sample may be prepared using laboratory techniques that separate sperm from seminal fluid and concentrate suitable sperm.

In certain situations, frozen sperm or surgically retrieved sperm may be used instead.

Step 6: Fertilisation

Once the eggs and sperm are available, fertilisation takes place in the laboratory.

There are two main approaches.

Conventional IVF

In conventional IVF, prepared sperm are placed together with the eggs in a laboratory dish.

The sperm are then allowed to fertilise the eggs without direct injection into the egg.

ICSI

Intracytoplasmic sperm injection (ICSI) involves injecting a single sperm directly into an egg using a specialised microneedle.

ICSI may be considered when there are specific male-factor fertility problems or previous difficulties with fertilisation.

It is not automatically required for every IVF cycle.

Step 7: Fertilisation Is Assessed

The laboratory checks the eggs after fertilisation procedures to determine whether fertilisation has occurred.

Not every egg will fertilise.

Factors affecting fertilisation may include:

Egg maturity
Sperm quality
Egg quality
Laboratory factors
The method of fertilisation

Patients may therefore notice a reduction in numbers as they move from:

Follicles → eggs → mature eggs → fertilised eggs → embryos

This is a normal part of the IVF process.

Step 8: Embryo Development

Following fertilisation, embryos are cultured in the laboratory.

Embryologists monitor their development over the following days.

The embryos undergo several developmental stages.

A fertilised egg initially divides into increasingly larger numbers of cells before reaching the blastocyst stage, typically around five to six days after fertilisation.

Not every fertilised egg will reach the blastocyst stage.

Why Don’t All Embryos Continue Developing?

Embryo development depends on several biological factors.

Some embryos stop developing naturally because of abnormalities that may prevent further growth.

This is one reason the number of embryos available for transfer or freezing may be lower than the original number of eggs retrieved.

The embryology team assesses embryo development to determine which embryos are suitable for the next stage.

Step 9: Embryo Transfer

Embryo transfer involves placing an embryo into the uterus using a thin catheter.

The catheter is passed through:

The vagina
Cervix
Into the uterus

The embryo is then deposited within the uterine cavity.

The procedure generally takes only a short time and does not usually require surgery.

How Many Embryos Are Transferred?

The number of embryos transferred depends on factors such as:

Patient age
Embryo quality
Previous treatment
Clinical circumstances
Applicable regulations and guidelines

Transferring more than one embryo can increase the chance of multiple pregnancy, which carries additional maternal and fetal risks.

For this reason, the decision about the number of embryos to transfer should be discussed carefully with the fertility team.

Fresh vs Frozen Embryo Transfer

Not every IVF patient has an embryo transferred during the same cycle as egg retrieval.

Fresh Embryo Transfer

A fresh transfer occurs during the same overall treatment cycle as ovarian stimulation and egg retrieval.

The embryo is transferred after several days of laboratory development.

Frozen Embryo Transfer

With a frozen embryo transfer, suitable embryos are cryopreserved after the IVF cycle and transferred during a later cycle.

A frozen transfer may take place during:

A natural cycle
An ovulation-induced cycle
A hormonally regulated cycle

The appropriate approach depends on the patient’s menstrual cycle, medical circumstances and treatment plan.

Step 10: Hormonal Support After Embryo Transfer

Hormonal medication may be prescribed after embryo transfer to support the uterine lining.

Progesterone is commonly used as part of luteal-phase support.

It may be administered through:

Vaginal medication
Oral medication
Injection

The exact medication and duration depend on the treatment protocol.

Patients should continue prescribed medication as instructed unless their fertility team advises otherwise.

What Should You Do After Embryo Transfer?

Patients are generally able to return home after the procedure.

Normal light activities are usually possible, although individual instructions may differ.

It is not necessary to remain completely immobile after embryo transfer.

Patients may be advised to avoid strenuous or high-impact activities for a period based on their clinic’s protocol.

There is no evidence that prolonged bed rest improves embryo implantation.

The embryo does not simply fall out because a patient stands, walks or uses the bathroom after the transfer.

Step 11: The Pregnancy Test

A pregnancy test is performed after embryo transfer to determine whether implantation has resulted in pregnancy.

The test usually measures beta-human chorionic gonadotropin (β-hCG) in the blood.

The timing varies according to the fertility centre and type of embryo transfer.

Testing too early can make interpretation difficult because hCG may not yet be detectable at sufficient levels.

Patients should therefore follow the testing date provided by their fertility team rather than relying on an early home pregnancy test.

What Happens If the Pregnancy Test Is Positive?

A positive blood test indicates that pregnancy has occurred, but further monitoring is still required.

The fertility team may arrange:

Repeat blood tests
Ultrasound
Early pregnancy monitoring

An ultrasound is generally performed later to confirm the location and development of the pregnancy.

A positive IVF pregnancy test does not guarantee that the pregnancy will continue normally, so follow-up remains important.

What Happens If the Pregnancy Test Is Negative?

A negative result means that the treatment cycle did not result in an ongoing pregnancy.

This can be emotionally difficult, but it does not necessarily mean that future treatment will not work.

The fertility team may review:

Ovarian response
Number of eggs retrieved
Fertilisation
Embryo development
Embryo transfer
Uterine factors
Sperm factors

If frozen embryos remain available, a frozen embryo transfer may be considered where appropriate.

Otherwise, the team may discuss whether another IVF cycle or a different treatment approach is suitable.

What Happens to Extra Embryos?

If there are suitable embryos remaining after the planned transfer, they may be cryopreserved for future use where appropriate.

Frozen embryos can potentially be used in a later frozen embryo transfer cycle.

This means a patient may not need to repeat ovarian stimulation and egg retrieval to use embryos that were already created during the original IVF cycle.

Embryo storage is subject to applicable regulations, consent requirements and storage arrangements.

What Are the Common Side Effects During an IVF Cycle?

IVF medications and procedures can cause temporary side effects.

These may include:

Abdominal bloating
Breast tenderness
Mood changes
Headaches
Injection-site discomfort
Pelvic discomfort
Mild cramping
Fatigue

Symptoms vary between patients.

Egg retrieval may also cause temporary pelvic discomfort or light vaginal bleeding.

What Is Ovarian Hyperstimulation Syndrome?

Ovarian hyperstimulation syndrome (OHSS) is a potential complication of ovarian stimulation.

It occurs when the ovaries respond excessively to fertility medication.

Symptoms may include:

Abdominal swelling
Abdominal pain
Nausea
Vomiting
Rapid weight gain
Shortness of breath in more severe cases

Most cases are mild, but severe OHSS can require medical treatment.

Patients should contact their fertility team promptly if they develop significant pain, marked abdominal swelling, difficulty breathing, heavy bleeding or other concerning symptoms after egg retrieval.

What Factors Can Affect the Outcome of an IVF Cycle?

Several factors can influence the chances of a successful outcome.

These include:

Maternal age
Ovarian reserve
Number of eggs retrieved
Egg maturity
Sperm factors
Fertilisation
Embryo development
Uterine factors
Previous fertility history

Age is particularly important for female fertility because egg number and quality generally decline over time.

Singapore’s current data also shows that maternal age and underlying medical history are important drivers of IVF success, with success rates declining with increasing age.

Does One IVF Cycle Guarantee a Pregnancy?

No.

IVF can improve the chance of pregnancy for appropriately selected patients, but no IVF cycle can guarantee a pregnancy or live birth.

A cycle may not result in pregnancy because:

No eggs are retrieved
Eggs are immature
Fertilisation does not occur
Embryos stop developing
No embryo is suitable for transfer
Implantation does not occur
A pregnancy is subsequently lost

These outcomes can occur even when the treatment has been carried out appropriately.

How Many IVF Cycles Might Be Needed?

There is no universal number of cycles that every patient should undergo.

The potential benefit of another cycle depends on:

Age
Ovarian reserve
Previous IVF response
Embryo development
Underlying fertility factors
Overall health
Personal circumstances

Current Singapore data emphasises that age and underlying medical history have a greater influence on IVF success than simply counting the number of cycles.

A fertility specialist can review the results of a previous cycle before deciding whether another attempt is appropriate.

How Is an IVF Cycle Different From a Frozen Embryo Transfer Cycle?

A complete IVF cycle usually involves ovarian stimulation and egg retrieval.

A frozen embryo transfer cycle uses an embryo that was already created and frozen during a previous IVF or ICSI cycle.

During a frozen transfer:

No new egg retrieval is required
Ovarian stimulation may not be required
The uterine lining is prepared
The embryo is thawed
The embryo is transferred into the uterus

The uterus may be prepared through a natural cycle, an ovulation-induced cycle or hormonal treatment, depending on the patient’s circumstances.

A Simple IVF Treatment Timeline

Although protocols vary, the process can broadly be understood as:

Before Treatment

Fertility assessment
Medical screening
Treatment planning
Consent and counselling

Ovarian Stimulation

Daily fertility medication
Ultrasound monitoring
Hormonal assessment where required

Final Maturation

Trigger injection
Egg retrieval scheduled at the appropriate interval

Egg Retrieval

Ultrasound-guided egg collection
Sperm collection and laboratory preparation

Fertilisation

Conventional IVF or ICSI where appropriate
Fertilisation assessment

Embryo Development

Embryo culture
Assessment of embryo development
Selection for transfer or freezing

Embryo Transfer

Embryo placed into the uterus using a thin catheter
Hormonal support provided where appropriate

Pregnancy Testing

Blood test at the scheduled time
Further monitoring if positive

This sequence may change depending on the treatment protocol and whether a fresh or frozen embryo transfer is planned.

How Can You Prepare for an IVF Cycle?

Preparation may involve:

Attending all monitoring appointments
Taking medication exactly as prescribed
Following instructions about medication timing
Maintaining a balanced diet
Avoiding smoking
Limiting alcohol
Taking recommended folate supplementation
Arranging time for appointments and procedures
Planning support around egg retrieval if needed

Patients should also discuss all prescription medicines, supplements and existing medical conditions with the fertility team before treatment begins.

An IVF treatment cycle involves several stages, beginning with preparation and ovarian stimulation and progressing through egg retrieval, fertilisation, embryo development and embryo transfer.

The process generally involves:

Ovarian stimulation
Monitoring
A trigger injection
Egg retrieval
Sperm collection and preparation
Fertilisation through conventional IVF or ICSI
Embryo culture
Fresh or frozen embryo transfer
Hormonal support
Pregnancy testing

Not every egg will fertilise and not every embryo will continue developing, so the number of embryos available for transfer may be lower than the number of eggs initially retrieved.

The exact IVF timeline and treatment protocol vary between patients. Factors such as age, ovarian reserve, previous fertility treatment, sperm factors and medical history can influence the approach.

For patients considering IVF in Singapore, understanding the stages beforehand can make the treatment process easier to navigate and provide a clearer idea of what to expect at each appointment.

This article is for general information only and should not replace medical advice from a qualified healthcare professional.