Thinking about freezing your eggs to have a baby later? Here are 3 numbers to help you decide

Angelica Cheng

Active Member

Egg freezing is promoted as an empowering option for women who want to stop the biological clock and improve their chance of having a baby later in life. But they need to know it’s more like a lottery than an insurance policy.

Fertility declines with age. To avoid age-related infertility, women increasingly turn to elective egg freezing. Advertising on IVF clinic websites and social media promote this as an insurance policy that allows women to start a family when the time is right for them.

But the reality is there’s no guarantee of a baby. The procedure is expensive and not risk-free. Most women need more than one egg collection for a reasonable chance of having a baby down the track. And, for a range of reasons, many women won’t use their stored eggs.

Typically, women who freeze their eggs are well educated, financially secure single women in their mid to late 30s. And contrary to the common stereotype that women freeze their eggs to advance their career or for other reasons to do with their personal fulfilment, the most common reason is they don’t have a partner or have a partner who is unwilling to commit to parenthood or is “not ready” to have children.

Quality of information on clinic websites

An assessment of the quality of the information about elective egg freezing on 21 Australian and New Zealand IVF clinic websites showed poor quality overall and a lot of room for improvement.

Only one clinic addressed the question about whether the data presented on the website were based on the clinic’s own experience or on published data from other clinics.

None of the clinics clarified if the data they gave related specifically to elective egg freezing, where most women are in their mid to late 30s, or if the data related to egg freezing in the context of egg donation, where eggs are retrieved from younger women with greater fertility potential.

Only two websites quoted the chance of having a baby as a result of elective egg freezing and only six websites provided information about cost.

Since we know people’s first port of call for health information is the internet, it’s possible this poor quality information – combined with the often upbeat and emotive images on clinic websites – can give women a false impression of what is possible with elective egg freezing.

Chances of success

So, what is the chance of having a baby with frozen eggs? These three numbers will largely determine your chance.

1) Your age when you freeze your eggs

To help women decide if and when to freeze their eggs, American scientists developed a prediction model which shows that for a 50%, 80% or 95% chance of a baby from frozen eggs a woman aged 35 or less needs to freeze six, 14, and 30 eggs respectively.

But for a woman aged 39, this goes up to 15 eggs for a 50% chance, 33 eggs for an 80% chance and 70 eggs for a 95% chance.

2) The number of eggs stored

Egg freezing involves a course of hormone injections to stimulate the ovaries to produce multiple eggs, ultrasound and blood tests to monitor the progress, and when the eggs are mature, retrieving them in a transvaginal ultrasound-guided procedure under light anesthetic.

The retrieved eggs are stored in liquid nitrogen until the woman returns to use them.

So, how many eggs can women expect from each egg retrieval?

According to data from all IVF clinics on Victoria in 2020, the average number of eggs collected per egg retrieval was 13 for women aged less than 35 years and ten for women aged 35-39 years.

3) How many cycles you can afford?

Each egg retrieval process costs between A$7,000 and $8,000 and unlike IVF, there is no Medicare rebate.

Based on the data above, an average 35-year-old woman can expect to pay $14,000-$16,000 and an average 38-year-old woman $21,000-$24,000 to store enough eggs for an 80% chance of a baby.

And if you return to use those eggs, you will need to pay to thaw them and inseminate them to create embryos. That process will add thousands to the overall cost.

What happens after freezing?

The longest follow-up study so far looked at the return rate among women who had stored their eggs for more than a decade. It found less than 40% had returned to use their eggs.

The most comprehensive data on what happens when eggs are thawed comes from the United States, where researchers calculated that for women under the age of 35, 41 eggs needed to be thawed for one live birth. This increased to 99 eggs for women aged between 38 and 40.

Women need the facts to make informed decisions

Elective egg freezing is taking off as a reproductive choice, which women are increasingly turning to for a range of reasons. They deserve:
  • comprehensive information about all the pros and cons of elective egg freezing
  • knowledge about the potential risks, including ovarian hyperstimulation syndrome (OHSS), a potentially serious condition caused by an excessive physical response to the hormone stimulation
  • transparency around the clinic’s own experience and track record
  • personalised estimates of how many eggs they need to freeze to have a reasonable chance of having a baby down the track.
Women need factual and realistic information about what is possible with elective egg freezing to make informed decisions and manage their expectations.

If we apply these numbers to the model, women in their mid to late 30s will likely need at least three egg retrievals for an 80% chance of having a baby from frozen eggs.

Singapore has made the unprecedented move of legalising egg freezing for women aged 21 to 35, which is expected to start in early 2023. Currently, the procedure is only allowed for women with medical conditions, such as cancer, who want to preserve their fertility.
Women are curious about the egg freezing process, including its success rate, costs and the technology involved. They also want to know: Where are the harvested eggs stored? Are there any risks involved, both in the procedure and in the freezing process? And can there be a situation where not a single egg harvested from a woman’s ovaries is usable – what happens then?

CNA Women delves into the egg freezing process to bring you the answers to these questions and more. Also, watch the video on what happens in the lab where harvested eggs are frozen and stored.
The costs are based on the number of egg retrieval cycles, and that two cycles are normally needed to retrieve sufficient healthy eggs.
The cost per egg retrieval cycle is on average S$7,000 to S$9,000 at KK Women’s and Children’s Hospital (KKH), said Associate Professor Sadhana Nadarajah, Head and Senior Consultant at Department of Reproductive Medicine at KKH. Subsequently, there is an annual charge for storage of about S$500.
On the other hand, the cost per cycle in private fertility clinics such as Virtus Fertility Centre ranges from S$10,000 to S$15,000 – which includes clinical consultation and assessment, ovarian stimulation, egg retrieval, egg freezing and storage for one year. Subsequent charges for storage start from S$900 yearly (excluding package pricing).

This means the cost can be up to S$25,000 for a comprehensive (comprising two egg retrieval cycles) egg freezing procedure, said Dr Liow Swee Lian, scientific director at Virtus Fertility Centre.
So if you’re 27 when you freeze your eggs and hope to get pregnant at 35, you would be paying storage fees that start from S$4,000.
If a woman wants to have a second child, the frozen eggs from one egg retrieval cycle are “typically insufficient”, Assoc Prof Nadarajah pointed out.
So a woman could go for two or three egg retrieval cycles to “bank” more healthy eggs for future use, said Dr Liow, ideally freezing a “minimum of 20 healthy eggs”.

“For a woman who is 30 years old and below at the time of egg freezing, she may have two successful pregnancies from 20 frozen eggs,” he explained.
Meanwhile, women aged between 31 and 35 years old may only have one successful pregnancy from 20 frozen eggs.
As egg quality decreases with age, it’s important to note that the older you are, the more egg retrieval cycles you’ll need to undergo to harvest and store healthy eggs.
According to a recent study that was published in the Journal of Obstetrics and Gynaecology in April this year, women aged 35 and below would require 10 to 15 mature eggs to have an 80 per cent chance of having a baby, Assoc Prof Nadarajah said.

Meanwhile, women aged 38 to 40 would require 25 to 30 mature eggs to achieve a live birth rate of 65 to 80 per cent. In this case, based on her egg quality and ovarian reserve, she would require three to six attempts of egg retrieval cycles to obtain the required number of mature eggs, she explained.
While an average of 10 to 15 eggs is usually harvested during the egg retrieval process, these also “include a number of deformed eggs and immature eggs which are not suitable for freezing”, said Dr Liow.
While it differs from patient to patient, he said you can expect to retrieve seven to nine healthy eggs in a cycle.

Studies have shown that a woman needs to freeze about 15 to 20 healthy eggs to achieve a live birth depending on her age and egg quality, explained Dr Sheila Loh, a specialist in Obstetrics & Gynaecology and Consultant at Raffles Fertility Centre.
This means women should be aware that two egg retrieval cycles are usually required to retrieve a suitable number of viable eggs, said Dr Liow.

And if your eggs are not usable in the first egg retrieval cycle, you can repeat another round of hormonal injections and egg retrieval procedure in the next cycle or in two months, he added.
At the end of the day, not all eggs will lead to a pregnancy or a baby, said Assoc Prof Nadarajah. “The success of egg freezing is heavily dependent on the quality and quantity of frozen eggs.”
Women should be aware that egg freezing (which involves the egg retrieval procedure), is an invasive procedure and there are surgical risks, such as risks of bleeding or infection, said Assoc Prof Nadarajah. The risks of complications, however, are “very low”, she added.
It’s also important to note: “While a woman’s frozen eggs do not age, she is still ageing,” Assoc Prof Nadarajah said.
She would still be at risk of developing medical conditions such as fibroids, endometriosis, high blood pressure and diabetes as she grows older. “These conditions may complicate the pregnancy,” she said.
There is also a “small risk” of ovarian hyperstimulation syndrome, said Dr Loh, which occurs when too many ovarian follicles have developed from the hormonal injections. If you manage to produce more than 20 eggs, she said, watch out for symptoms such as severe bloating, shortness of breath and abdominal pain. The chance of it occuring in egg freezing cases is, however, “rare”, she added.

Dr Liow Swee Lian, scientific director at Virtus Fertility Centre, lists the steps a woman who wants to freeze her eggs would go through.
  • Step 1: Book a consultation with a fertility doctor who will do an ultrasound scan to check on the general health of the womb and fallopian tubes, as well as order a blood test to look at your hormonal profile.
  • Step 2: If your scan and test show that you are suitable for egg freezing, the process will start on Day 2 of your menstrual cycle, where you’ll self-administer hormonal injections at home to stimulate egg production (also known as ovarian stimulation). You’ll do these daily injections for about two weeks.
  • Step 3: During the two-week period, you’ll have to head to the clinic for one or two days for ultrasound scans and blood tests, to track your progress and monitor the growth and development of the follicles, which contain the eggs.
  • Step 4: On day 10 of the menstrual cycle, you’ll be given a “trigger shot” of the human chorionic gonadotropin (hCG), a hormone produced during pregnancy, to “mature the eggs” or trigger ovulation, said Dr Liow. The eggs will be retrieved 34 to 36 hours later, which usually coincides with Day 14 to Day 16 of the menstrual cycle. The procedure is done under general anaesthesia and takes less than 30 minutes.
  • Step 5: The harvested eggs will be processed in the lab. Immature eggs will be grown in the incubators for 24 to 48 hours till they mature. Only mature eggs will be selected for freezing in a process called vitrification – a process that ensures the egg is not damaged.
  • Step 6: The frozen eggs are then stored in “specialised straws”, before submerging them (typically two eggs in one straw) in tanks filled with liquid nitrogen at a temperature of -196 degrees Celsius.
  • Step 7: When you and your partner are ready to have a baby, the eggs will be “warmed” to body temperature (37 degrees Celcius) and fertilised with sperm via in-vitro fertilisation (IVF). Note that in Singapore, IVF is allowed only within the confines of marriage.


Egg retrieval is the most invasive part of the process, where a “long thin needle” is inserted into the ovaries via the vagina to retrieve the eggs, explained Dr Liow. This is done under general anaesthesia, and takes no longer than 30 minutes – usually 10 to 15 minutes, he added.

During the egg retrieval procedure, an aspirating needle is inserted through the vagina to retrieve the eggs. The outpatient procedure will take no longer than 30 minutes. (Photo: Merck)

Immediately after the procedure, you’ll remain in the hospital or fertility clinic for about two to three hours to allow the anaesthesia to wear off before going home. “It is advisable to have a close friend or family member to send you home as you may experience some nausea or dizziness,” explained Dr Loh.
“The most common side effects following egg retrieval are vaginal soreness, abdominal cramping, spotting and bloating, which can cause discomfort,” Dr Liow said.

These side effects are normal, he said, and patients typically are able to resume normal activities within a few hours, and fully recover within a couple of days.
At the same time, some women may also find that the hormone stimulation drugs (which are self-injected throughout the cycle prior to egg retrieval) cause them “discomfort and pain”.
In ovarian stimulation, you’ll need to self-administer hormonal injections at home to stimulate egg production. You’ll do these daily injections for about two weeks.
When it’s time for the egg retrieval procedure, Dr Liow recommended that women take a day’s leave for it.

The most common side effects following egg retrieval are vaginal soreness, abdominal cramping, spotting, and bloating, which can cause discomfort.

Dr Loh advised taking it easy with work commitments and reducing “heavy physical exercises” when you are undergoing ovarian stimulation and egg retrieval procedure. “The enlarged ovaries (from ovarian stimulation) may be painful and can twist, causing complications,” she explained.
She added you should also avoid consuming alcohol and/or smoking for at least two months before the ovarian stimulation process.

From 2023, women aged 21 to 35 can go for elective egg freezing in Singapore. But what’s the process like? CNA Women had an exclusive behind-the-scenes look at Virtus Fertility Centre.
It is similar to that of couples undergoing IVF, said Dr Loh. After your eggs are retrieved, consider resting for another three to seven days as the ovaries may feel “sore and heavy”. Complete bed rest isn’t necessary, however.
The fertility experts that CNA Women spoke to said the eggs are stored in receptacles (or “straws”), which are submerged in storage tanks filled with liquid nitrogen at a temperature of -196 degrees Celsius.
According to Dr Liow, two eggs are typically stored in one straw.

Frozen eggs are stored in specialised straws (see coloured sticks), before submerging them in tanks filled with liquid nitrogen at a temperature of -196 degrees Celsius. Two eggs are typically stored in one straw. (Photo: Kelly Hui/CNA)

The short answer is no – they remain the same age as when they were retrieved from your ovaries.
“When eggs are frozen, they are frozen in time, and are stored in a state of hibernation,” said Dr Liow. They do not get older “regardless of how many years later they are used”. So if you decide to freeze your eggs when you’re 32 years old, your frozen eggs will remain 32 years old forever.
“In theory, they can be kept for many years with minimal risk of deterioration in quality. However, we recommend that they be kept for not more than 15 years,” said Dr Liow.

And while there is currently no age limit for when a woman has to use her frozen eggs, Dr Liow pointed out that maternal age has an impact on pregnancy outcome. “Women who are at an advanced age have higher risks of complications in their pregnancies,” he said.
It’s crucial to monitor the liquid nitrogen in the storage tank to safeguard the quality and viability of the frozen eggs in the long term, said Yong Yin Yin, a principal embryologist at Raffles Fertility Centre.
“Storage tanks are fitted with sensors and a continuous monitoring and alarming system that sends us alarms in the event of any failure or conditions that might damage the frozen eggs in storage,” she explained.

The liquid nitrogen is consistently topped-up in the storage tanks, too, she added. This helps ensure the storage tanks will not “dry out”.
Should there be a need to, there are back-up storage tanks that are “pre-filled (with liquid nitrogen) at all times” to transfer the frozen eggs into a “more secure” tank, she explained.
The fertilisation rate for frozen eggs is as good as “fresh” eggs – an average of 80 per cent, Dr Liow said. “This is because an ultra-rapid freezing process, called vitrification, ensures the egg is not damaged, with a survival rate of almost 100 per cent,” he explained.

This technique, which became a “routine practice” about a decade ago, gives a better outcome as compared to the older method of slow freezing, added Assoc Prof Nadarajah.
According to a 2017 study in the US discussing the past and current trends of the vitrification method, the benefits of vitrified embryos and eggs were gaining worldwide acceptance by 2010.
According to Dr Liow, you can choose to either donate them to other couples anonymously or donate them for research and development purposes. You can also opt to dispose of them outright, he added, which “many couples” often opt to do.
Yes, the frozen eggs can be transferred to another facility with the woman’s consent, said Dr Liow. The woman would be the owner of the frozen eggs, even if she marries in the future; there is no joint ownership of frozen eggs.
“Specifically designed transport canisters are used to ensure the eggs are protected and maintained at the appropriate liquid nitrogen temperature,” he said.
Hence, it is “very safe” for sperm, eggs and embryos to be transported between clinics, around the world, on a regular basis, he added.
Let the clinic know that you and your husband are ready to proceed with fertility treatment so you can meet with the fertility specialist to discuss the process, said Dr Liow.

Then you will consult with their fertility specialist again to begin the IVF cycle at the start of your menstrual cycle.
On the day of ovulation, your husband provides a sperm sample, whereupon the eggs will be “warmed” and inseminated with the sperm. More than 30 years ago, IVF would involve the sperm and egg being placed in a petri dish while an embryologist waits for the sperm to fertilise the egg on its own, said Dr Liow.

According to Dr Liow, Intracytoplasmic Sperm Injection (ICSI), a fertilisation process where the "best sperm" is injected into the egg, is considered a standard IVF protocol in Singapore. Many clinics around the world, including Australia, use a combination of IVF and ICSI depending on the couple's fertility challenges. (Photo: Kelly Hui/CNA)

Since 1992 however, fertility clinics now use a process called Intracytoplasmic Sperm Injection (ICSI), where “a single sperm is injected into each egg to assist fertilisation using very fine micro-manipulation equipment”, he added.
As an additional part of the IVF cycle, the technique ensures that the “best sperm” is directly injected into the egg – offering a “significant increase in fertilisation and pregnancy rates, and a reduction in miscarriage rates”, said Dr Liow.

4 Things Young Women Should Consider Before Freezing Their Eggs

Egg freezing is currently banned in Singapore with the exception for those with specific medical reasons. However, on 28 March 2022, the government released a White Paper on Women’s Development which details action plans to be implemented over 10 years. One of the proposed directives is the ratification of the Assisted Reproduction Services Regulations under the Healthcare Services Act. If approved, this new development will allow women aged 21 to 35 years old to undergo elective or social egg freezing regardless of their marital status.

This means that they will be able to retrieve healthy eggs for preservation even before they are at the stage of actively trying to get pregnant. What exactly is egg freezing, and how does it work? And what should a young woman take into consideration before opting for this medical procedure?

How Does Egg Freezing Work?

Egg freezing, known technically as oocyte cryopreservation, refers to the process of freezing a woman’s eggs. The eggs are removed through an in-vitro fertilisation (IVF) procedure from the ovaries, then stored at below freezing temperatures to be used potentially at a later time. In essence, egg freezing stops the clock from ticking by keeping eggs viable long after the others within the reproductive system have run out.

Egg freezing is one of the ways to maintain fertility. Women may choose this method for a number of reasons, including mitigating health problems such as endometriosis, which causes uterine tissue to grow outside of the womb and may result in infertility.

What to Consider Before Freezing Your Eggs

Given the significance of this procedure, it is important to understand the potential risks and implications that come with it.

1. Financial cost

Egg freezing literally allows you to buy time. However, this often does not come cheap. On average, one egg freezing cycle in Singapore can cost upwards of $8,000, which can be a hefty sum for many people. This amount also does not include storage fees, which can cost $600 each year.

2. Side effects from fertility drugs

To harvest healthy eggs, you will first need to take certain fertility drugs. Medications such as hormone injections help to stimulate the ovaries to produce an optimal number of eggs. However, these drugs do come with potential uncomfortable side effects. Apart from injection site bruising, you may experience:

  • Nausea and vomiting
  • Headaches
  • Cramps
  • Breast tenderness

They may even lead to Ovarian Hyperstimulation Syndrome (OHSS), which means your ovaries swell and become rather painful.

3. Risks from medical procedure

All medical procedures come with some degree of risks, and egg retrieval is no different. The eggs are retrieved using transvaginal ultrasound aspiration, which involves the use of an aspiration needle. While complications are rare, this intrusive procedure increases your risk of bleeding, infection, or even damage to the bladder or bowel. However, one should also understand that this does not mean egg freezing should be avoided – but rather, that medical procedures like this naturally come with its own set of risks.

4. No success guarantee

While egg freezing can increase your chance of becoming pregnant in the future, it does not guarantee that this will happen. The overall success rate is dependent on several factors, such as the quality of the eggs, and a woman’s age during the time of retrieval. Also, not all eggs will make it through the thawing process, and not all eggs may be fertilised by the sperm.

Seek Advice From The Experts

Egg freezing is not a fertility insurance policy, and should not be treated as such. Given the limitations and benefits of this procedure, it is crucial to understand the considerations and risks associated with egg freezing treatments. You must also ready yourself for the emotional toll this can take on you, should your eggs end up not becoming fertilised at the end.

At The O&G Specialist Clinic, we are delighted to see young women in Singapore being given the chance to take charge of their own fertility outcomes. While we anticipate that social egg freezing would become a norm in future for women across all ages, the fact of the matter is that this is still a serious medical procedure that should not be undermined.

Egg freezing may not be your only option. Book a virtual consultation to discuss your fertility management options, or read more about the views of our professional fertility specialist and founder, Dr Loh Seong Feei, on The Straits Times (‘Singapore to allow women, including singles to freeze their eggs, for non-medical reasons’) and Lianhe Zaobao (‘让女性结婚生子有更大自主权 冻卵能避免卵子素质下降导致不孕’) today.