Despite the huge uptake in elective egg freezing, it’s a relatively new procedure, so doctors and scientists are still building up the empirical data to understand the full risk profile.
While taking medication and during the retrieval procedure itself, you'll be under the care of trained fertility specialist doctors and nurses whose number one job it is to keep you safe. But, as with any medical procedure, there are some potential long and short-term health risks - some to your physical health and some to your emotional wellbeing (think: how will you feel if it doesn't work?)
The data that does exist for egg freezing cycles tends to focus on non-healthy women, given the fact egg freezing only used to be done for medical reasons. This dataset is small - some figures suggest that only seven percent of women have so far “gone back” to use their eggs161 - and, though it is informative, the data is not necessarily representative of healthy women undertaking egg freezing. As more and more healthy women go back to use their eggs that were frozen for age-related reasons, a more specific dataset will evolve. In the meantime, much of what is understood about the risks and safety of egg freezing is derived from studies that looked at IVF cycles.
So while over 2.4 million cycles of ovarian stimulation take place each year around the globe,162 the ASRM cautions that there is not enough data now to know all the possible risks. The organization’s guidelines state, “while short-term data appear reassuring, long-term data on developmental outcomes and safety data in diverse (older) populations are lacking.”163
Before we get into more specific risks and side effects, let’s cover some common, broader
findings that address concerns you might have:
Egg freezing is regarded as safe
Despite their caveat about the size of the dataset, the American Society for Reproductive Medicine (ASRM) says that:
“Most of the medical procedures involved in planned egg freezing are well established; ovarian stimulation, oocyte [egg] retrieval, embryo culture, and embryo transfer are all regular components of IVF that are well tested, used worldwide, and regarded as safe.”164
The risks of egg freezing are similar to those associated with ovarian stimulation before IVF. If you have concerns, raise them with your doctor.
No causal link with cancer has been identified
This is a common fear based on reports that women receiving fertility treatment have higher
rates of cancer (e.g. breast, endometrial, and ovarian), but in studies, no causal link has been
identified. While some studies suggest an increased risk of cancer, most do not.165 166 167 168 169 170 171
Researchers believe the correlation might be explained by surveillance bias172 (women undergoing ART treatment undergo scans and ultrasounds which increases the chances that
cancer will be found) or patient profiles (women who need fertility treatment are already more
at-risk as a group).173 174 175 Studies have shown that even women with breast cancer are not
more likely to have a recurrence if they undergo ovarian stimulation.176
DOCTOR INSIGHT: “In general, older studies linking increased cancer risk to fertility
treatment suffered from methodological limitations – mainly failing to find an appropriate
control, or control for confounders like infertility itself, which is linked with increased risk of
cancer. The increased cancer risks noted were deemed due to differences in underlying risk
factors in infertile patients compared to fertile patients, rather than the treatments. It is generally
well accepted that there is not an increased risk of invasive breast, ovary or thyroid cancer
related to fertility treatments. Long-term studies are ongoing.” - Dr. Eleni Greenwood Jaswa, University of California, San Francisco
DOCTOR INSIGHT: “Hormonal therapy itself does not cause cancer. It can, however,
stimulate the growth of cancerous cells. Therefore, if a person currently has cancer, or has a
higher risk of developing cancer due to their unique genetic composition, hormonal therapy
would be contraindicated. Before administering any hormonal therapy (for infertility or
otherwise), doctors should screen their patients for any genetic abnormalities that may
predispose the patient to cancer.” - Dr. Aimee Eyvazzadeh, Private Practice Physician, San Ramon
DOCTOR INSIGHT: “If a woman is in any way concerned because of age or family history
I suggest a baseline mammogram before starting stimulation.” - Dr. Diana Chavkin, HRC Fertility, Los Angeles
DOCTOR INSIGHT: "Infertility is an independent risk factor for breast/uterine/ovarian
cancer, however the treatments used [ovarian stimulation etc.] do not pose additional risk." - Dr. Meera Shah, Nova IVF, Mountain View
In essence, women who experience infertility are known to have higher rates of female
cancers (which accounts for some of the scare stories), but these cancers are not caused by the
fertility treatments. Research is still ongoing into the reasons for the link. Every one of the
fertility doctors on our expert panel say there is no robust evidence that egg freezing will
increase your risk of cancer, nor is there clear biological plausibility.
The only risk may
potentially be in women who already have breast cancer, because the hormones in an egg
freezing cycle may stimulate it in a minor way, but this is still considered "irrelevant." Despite
these reassurances, if you have concerns, especially if you have a family history of cancer, make
sure to raise them with your own doctor.
Egg freezing does not reduce your risk of having a natural birth in the future
A common misconception is that by stimulating and freezing multiple eggs, you are “using
up” eggs from your ovaries that could be used for a natural birth in the future. Don’t worry,
that’s not the case. You would have lost those follicles and eggs regardless. In a normal month,
your body loses around 1,000 follicles, of which only a single one usually matures to the point of
ovulation.177 You would also lose these eggs if you were taking birth control pills or during
pregnancy. If it was actually the case that you have a certain number of eggs and you ovulate
until they run out, stopping ovulation by taking birth control pills would then surely delay menopause! (Unfortunately that’s not the case.)
In an ovarian stimulation cycle for egg freezing, what happens is that a few of those other spare 999 follicles, which would normally be reabsorbed into the ovary (or “lost”) that month, are stimulated into the next stage of maturation and retrieved by your doctor. You’re effectively making use of some of the spare capacity.
The fact of the matter is, you will only ovulate around 500 times in your lifetime out of all the
millions of eggs you started with: 99% of the follicles are wasted.178 There are plenty to spare for
multiple cycles of egg freezing. In short, doing IVF or an egg freezing cycle does not lower your
chances of fertility in the future, nor does it cause you to have menopause at an earlier age. This
is because the eggs that are retrieved are eggs that would have been lost regardless.
Babies from frozen eggs are not more likely to have birth defects
About one in every 33 babies is born with a birth defect, also called congenital disorders.
Not all birth defects can be prevented, though age is a big risk factor. Babies born via ART with
frozen eggs show no more likelihood of having congenital anomalies than those born via ART
treatments using fresh eggs.179 180 As such, there’s not thought to be any difference in risk using
fresh or frozen eggs. Even before the new, improved freezing technology came along, by 2009
more than 900 babies were born from frozen eggs and according to a committee from the
ASRM, there was no apparent increase in congenital anomalies among these babies.181 182
However, babies born via ART are seen to have more congenital anomalies when compared
to naturally conceived children.183 184 185 186 187 188 Studies vary, but it’s suggested that this amounts to slightly increased risk.189 The thing is, this may be a case of correlation, not
causation. Babies born to infertile couples also have higher rates of congenital anomalies
whether they were conceived naturally or via ART, which is why some researchers say this
indicates the treatment itself might not be the cause.190
So, if there’s not necessarily a risk because of the actual technological process, why the
slightly increased percentage of ART babies born with birth defects? Researchers make the point
that women undergoing ART are already at higher risk of having babies with birth defects
because of their riskier profiles: infertile women are more likely to be older, obese and to have
chronic health conditions (like diabetes, high blood pressure, and epilepsy), all of which are
independent risk factors for congenital anomalies in the first place.191 192 193 194 Women who have experienced a hard time getting pregnant or staying pregnant and who have turned to ART to help them have a baby may also have a higher threshold for abortion, given the challenges they have faced, possibly leading to more babies born with birth defects. ART pregnancies are also more closely monitored than general pregnancies, so more congenital anomalies may be
identified simply because more are diagnosed and recorded. There are plenty of plausible
explanations for the slightly increased risk that mean it’s not actually to do with the process
It’s now generally agreed that there is no difference in likelihood of having a healthy baby
whether a fresh egg or a frozen egg is used. However, we should point out that the fresh v. frozen
studies done were primarily on women under the age of 35 years old - there haven’t been similar
ones on women older than that, so nobody can say for sure if there might be a difference after
that age. With that said, studies are still ongoing into the link between ART and birth defects and
more research is needed before the picture is crystal clear.195
Other pregnancy risks are probably not to do with the process itself
What is clear from the data is that women who undergo IVF are more likely to have twins,
triplets and other riskier multiple pregnancies. However, that is usually as a result of doctors
transferring more than one embryo into the womb, rather than because of the fertility treatment.
It is generally considered now that single embryo transfer is best for the health of mother and
baby. Ectopic pregnancy (when a fertilized egg doesn’t properly attach to the womb) and the
pregnancy complication preeclampsia (with symptoms including high blood pressure) appear to
be more common in assisted conception than in natural conception. However, researchers think
that the increased risk of these conditions is most likely related to a woman’s fertility problems
and the fact she’s more likely to be carrying more than one baby at a time.”196 As a result, it’s
not thought to be the actual processes of assisted conception increases these risks.
The Side Effects
You can expect some short term side effects
The short-term side effects of the procedure are clear and are generally minor. (Long term
side effects are considered safe, but, as with all things in egg freezing, are still being studied.)
While there are usually no dramatic or serious side effects, the main thing you should expect
is that during and immediately after ovulation stimulation and egg retrieval, your ovaries will be
enlarged due to the stimulation hormones, which can feel really uncomfortable. For most
women, this temporary bloating and some PMS-like symptoms are the extent of the egg freezing
side effects. These side effects should only last for the days the medication is taken and subside a
few days after the procedure. There are some other things to watch out for though:
● Bloating - During stimulation and for several days after retrieval, a degree of abdominal
bloating is common and expected.
● PMS-like symptoms - This might include headaches, mood swings, insomnia, hot or
cold flashes, breast tenderness, mild fluid retention.
● Fatigue - This isn’t just when recovering from the sedative after retrieval, but can
manifest during the hormone injection period, too. Think of it a bit like how your energy
levels can fluctuate during your menstrual cycle along with hormones.
● Bruising - The hormone injection site on your abdomen could become sore, red, or
slightly bruised. Switching up the injection site throughout the process can help with
● Grogginess after retrieval The sedative used for the retrieval procedure is similar to
that used by dentists for wisdom tooth extractions. It’s commonly a propofol-based
sedation medication sometimes called “twilight” anesthesia or a “deep sleep” and is
monitored anesthesia care. It carries an extremely low risk of complications and doesn’t
require a breathing tube. Still, you’ll probably feel groggy afterward as it wears off (like
a sleeping pill), which is why you won’t be able to drive home.
● Cramping - After the retrieval procedure, some women report feeling discomfort
around the ovaries and lower abdomen due to puncture sites on the ovary and the vagina.
● Menstrual cycle problems - rare - Your menstrual cycle should return to normal with a
period one to two weeks following the procedure, though some women do experience
spotting. Speak to your doctor if you do not get a period within two weeks of the
procedure. The next period is sometimes delayed as the body “resets.”
● Bleeding or infection - Bleeding as a result of the procedure can happen, but this is
extremely rare. If you experience symptoms like the ones below call your clinic.
According to Dr. Eleni Greenwood Jaswa, “Bleeding after a procedure may accumulate
in the belly and cause abdominal/pelvic pain, shoulder pain (the nerves irritated by blood
in the abdomen are sensed in the shoulder), dizziness, lightheadedness, feeling faint or
weak. Often, women who have procedural bleeding into their belly will not seeing
● Infection - Infection as a result of the procedure can also happen, but this is also
extremely rare. Some clinics may give antibiotics to prevent infections.
● Moderate Ovarian Hyperstimulation Syndrome (OHSS) - Affects less than 5% of
women - Mild-to-moderate ovarian hyperstimulation syndrome involves fatigue, nausea,
headaches, abdominal pain, breast tenderness, and irritability, but these adverse effects
can usually be well-controlled.197
● Severe Ovarian Hyperstimulation Syndrome (OHSS) - Affects less than 1%. (Many
clinics have been replacing the use of hCg as the trigger shot with GnRHa instead,
which advocates of that treatment protocol say has greatly decreased OHSS, in the last 5
years, especially in at-risk women.) 198 - Symptoms of moderate OHSS include extreme
bloating, thirst and dehydration. You may only pass small amounts of urine, which are
dark in color, and/or you may experience difficulty breathing, abdominal pain,
dehydration, and vomiting. A serious, but rare, complication is the formation of a blood
clot (thrombosis) in the legs or lungs. The symptoms of this are a swollen, tender leg or
pain in your chest and breathlessness.199A very small number of deaths due to OHSS
have been reported. Although there is no treatment that can reverse OHSS, it will usually
get better with time.200 Severe OHSS can be thought of as the loss of control over
stimulation of the ovaries.201 With careful dosing and monitoring, most cases can be
avoided. If you have concerns about OHSS, raise these with your doctor. Note that the
risk is higher if you are under 30 years old (as you are more likely to have a higher
number of eggs),202 if you’ve had OHSS before, if you have PCOS, 203 204 or if you have
other medical problems like hypertension, diabetes, obesity, hypothyroidism or anemia.
● Anesthesia risk - Less than 1% risk of difficulty breathing and low blood oxygen for
women of normal weight, but of more concern for obese women.206 Where general
anesthesia is used, it comes with its own set of risks, which is proportionately higher for
women that are obese. This is why many clinics have upper limits for BMI for the
patients they will treat. Make sure to let your doctor or nurse know if you have ever had a
reaction to an anesthetic or sedative, or if you are allergic to any medications.
● Damage to nearby organs like bowel/bladder/blood vessels - Less than 1% risk. The
procedure is performed under transvaginal ultrasound guidance to avoid this
● Ovarian torsion - Though very rare, an ovary may twist around the ligaments that hold it
in place, potentially cutting off blood flow to the ovary and fallopian tube.208 The chance
is slightly increased due to their enlargement. To avoid ovarian torsion, many clinics
recommend avoiding vigorous exercise during and after the treatment cycle until the
ovaries have returned to their normal size. 209
● Pregnancy - Although rare, this can happen. A lot of clinics recommend not having sex
during an egg freezing cycle.
Your own medical history and individual health may mean an increased risk of one or more
of these side effects, so always discuss these with your doctor at length.
“I felt fine most of the time. I just felt a bit tired.” - Shannon, 36
“I found the bloating really, really uncomfortable. I couldn’t sit still and things didn’t
properly go back to normal until about a week after my procedure.” - Hannah, 33
DOCTOR INSIGHT: “Feeling fatigued is probably the most common complaint/feedback I
get during stimulation and is not necessarily due to OHSS. I tell my patients, when counseling
them on how they may feel, is that in almost 30 years of doing this, I cannot remember a single
patient who stopped her medications prior to egg retrieval due to side effects.” - Dr. Diana Chavkin, HRC Fertility, Los Angeles
Other things to bear in mind
NOT ALL DATA IS CREATED EQUAL
Though egg freezing has only become way more popular in recent years, it's not a new procedure by any measure - in fact, the first baby born from a frozen egg is now over 30 years old.
Since then, treatment protocols, equipment and attitudes have all evolved, so some of the stories and stats you hear from years ago don't accurately reflect outcomes now - just keep an awareness of this whilst doing your research. (And if you're unsure of anything - ask your doctor directly.)
EGG FREEZING MIGHT NOT BE FOR EVERYONE
Understanding the statistical outcomes as they are likely to pertain to you individually is a CRUCIAL part of your preparation. There may be egg freezing considerations or risks specific to you and your health. When you go into a fertility clinic, your doctor will take your full medical history. Along with preliminary tests, this will determine whether you are what they might call a good "candidate' for the procedure.
They should also let you know about any egg freezing side effects or procedure-related risks as they pertain to you individually based on your general health.
IT'S NOT QUANTITY THAT MATTERS, IT'S QUALITY
"How many did you get?!"
Get ready, that's the first question you'll hear from anyone you tell you froze your eggs. You may have found that there are a variety of perspectives on exactly how many eggs you want to have retrieved in order to secure a live pregnancy in the future. The more eggs you have frozen, the more chance of them making a baby in the future.
BUT what also really matters is how many of those are of a quality worth keeping - the elites. These are the eggs most likely to be abnormality-free, freeze well and make an embryo.
Quality is key because 95% of embryo health comes from the egg so, in theory, high quality eggs produce high quality embryos. Embryos must be strong enough to survive the early stages of development in order to have a successful pregnancy in the future. Poor quality eggs can can mean the difference between carrying your baby to term, or losing it in the first few weeks if it doesn’t implant properly.
Whilst freezing enough eggs to increase the overall chances of a successful birth in the future, studies show that more hormones might equate to more eggs, but those eggs start competing with each other and thus the quality is sacrificed. As such, the current thinking is that freezing more than 20 eggs in one "cycle" could potentially impact quality, though more research is needed in this area.
THIS IS AN INSURANCE POLICY, NOT A GUARANTEE
Egg freezing is a wonderful way to improve your odds of being able to future-proof your fertility, but - as every healthcare provider should be upfront in telling you - there are no guarantees.
The pre-screening tests are there to give you the best idea on how many eggs you might produce and how many end up being frozen but this is an indication using all the inferences available, rather than an absolute.
Also, whilst egg freezing and fertility technology is advancing at an incredible rate, there are situations down the line that can also affect the usability of your eggs, which you should be aware of:
Storage facility failure - this is very rare but has happened.
While studies indicate that there is no "expiration date" for your eggs, some countries like the UK have laws that prevent you from storing them for more than 10 years. This is an important consideration when choosing a country to store them. South Africa and the US have no limit.
The reality of needing multiple cycles. Depending on your age and the number/quality of eggs retrieved, there's a chance that you'll need to undergo multiple cycles in order to further futureproof your fertility. In almost all circumstances, your doctor will have a good indication of whether or not this is the case and will discuss your options accordingly. Just think, more chances to come on a fabulous retreat!
Of the eggs that are retrieved, some may not be suitable for freezing, some may not survive the freezing and thawing processes and some may not fertilize or develop into normal embryos. Of the embryos that are transferred, only some will result in a pregnancy, and some pregnancies miscarry. Freezing your eggs is no guarantee of a baby, it's a way of storing your own young eggs so that you have the potential to use them in IVF treatment (rather than, let's say, using donor eggs) if you ever need it. As such, IVF success rates are a good guideline.
THIS IS A DECISION ONLY YOU CAN MAKE FOR YOU
We've gone through the exact same process you are going through right now. It's totally normal if you're feeling overwhelmed, like you're coming across a whole lot of sometimes conflicting data and opinions that are holding you back from actually making a decision on this. Particularly the scaremongering stories that don't seem to be based in any actual facts.
But know that reading things like this, considering your options and educating yourself about your fertility health and your options is only a good thing. We don't have full control over a lot of things in life - fertility included. But once you balance all the inputs you are better able to know whether taking the step to freeze your eggs is going to feel to you like it does offer you that bit more security.
We're on a continual mission to streamline all the information and make sure that you are able to formulate your own opinions/decisions so please let us know if you want to ask a question or flag up something we should cover