Most people leave egg retrieval sore, a little crampy and puffy around the middle. That is normal. Your ovaries have just grown a whole cohort of follicles at once, and they stay enlarged for a while after the eggs are collected. A small number of people go further than that, into ovarian hyperstimulation syndrome (OHSS), where fluid shifts out of the blood vessels and collects in the abdomen and sometimes the chest.
This guide is for the days right after retrieval: what the warning signs are, which numbers on a scale should make you pick up the phone, what your clinic may already have done to lower your risk, and how to plan the days after retrieval if you have travelled for treatment. It is educational and it is not a substitute for your own clinic's instructions. If anything below sounds like what you are feeling right now, call your clinic before you read on.
Call your clinic or seek urgent care now if you have
Difficulty breathing, vomiting that will not stop, trouble keeping fluids down, a noticeably swollen or tight abdomen, passing much less urine than usual, sudden abdominal pain, or swelling, redness or pain in one leg. ASRM's patient fact sheet also lists a weight gain of more than three pounds in two days as a reason to call (ReproductiveFacts, ASRM, 2023).
What OHSS actually is
Stimulation drugs push many follicles to grow at the same time. The hormone signal that completes egg maturation (the trigger shot, and later any pregnancy hormone) can make the enlarged ovaries release substances that make blood vessels leaky. Fluid then moves from the bloodstream into the abdominal cavity. That is why the symptoms are about fullness, fluid and, in serious cases, dehydration and clotting, rather than about the ovaries themselves hurting.
Mild symptoms are common. Both ASRM and the UK regulator put mild OHSS at roughly one in three people having ovarian stimulation for IVF (ReproductiveFacts, 2023; HFEA, 2016). Moderate and severe forms are less common. The HFEA notes severe cases are rarely life-threatening, and ASRM describes the serious complications as usually avoidable when treatment starts early. Neither source publishes a single percentage for severe OHSS, so treat any precise figure you see online with caution and ask your own clinic for its numbers.
Mild, moderate and severe: a practical comparison
| Level | What you might notice | What usually happens |
|---|---|---|
| Mild | Bloating, mild abdominal discomfort, some nausea, a little weight gain from fluid | Rest, fluids, pain relief your clinic approves, and a check-in call |
| Moderate | The same symptoms, more pronounced; clothes tight at the waist; appetite down | Closer follow-up with ultrasound and blood tests; outpatient care in most cases |
| Severe | Persistent vomiting, inability to keep liquids down, marked abdominal swelling, breathlessness, signs of a leg clot | Same-day assessment; possible fluid drainage; rarely, hospital admission |
The categories above follow the descriptions in ASRM's fact sheet. Clinics grade OHSS using their own criteria, which also take blood results and ultrasound findings into account, so your nurse may describe your situation differently.
When symptoms tend to appear, and how long they last
Timing helps you interpret what you feel. The HFEA says stronger symptoms usually show up in the week after egg collection. ASRM describes symptoms as typically beginning a few days after ovulation (in IVF, after the trigger and retrieval) and usually settling within about two weeks if there is no pregnancy.
Pregnancy changes the picture. If a fresh transfer leads to a positive test, the pregnancy hormone can keep OHSS going or make it worse. ASRM notes symptoms in that situation often last two to three weeks or longer, while the pregnancy itself is generally not affected. This is one of the main reasons clinics freeze embryos instead of transferring when risk is high: no pregnancy hormone in that cycle means the ovaries can calm down on their own schedule.
Who is more likely to develop OHSS
Risk follows ovarian response. People who grow a large number of follicles are the main group clinics watch. ASRM lists a high AMH and polycystic ovary syndrome (which its fact sheet notes is now also called PMOS) as risk factors, and points out that low ovarian reserve does not raise risk. Your monitoring bloodwork and follicle counts during stimulation are how your team spots a high response before trigger day.
If you have been told you are a likely high responder, it is reasonable to ask before stimulation starts: what is the clinic's plan if I grow a lot of follicles? A good answer names specific steps, not just "we'll monitor you."
How clinics lower the risk before it starts
Most of the work against OHSS happens on the clinic side, before and on trigger day. The European Society of Human Reproduction and Embryology (ESHRE) reviewed the evidence in its ovarian stimulation guideline (2025 update). In plain terms, its recommendations include:
- Choosing the antagonist protocol for people predicted to respond strongly, and using a more modest starting dose of FSH to reduce risk.
- Using a GnRH agonist trigger instead of hCG for people at risk, combined with freezing all embryos. ESHRE gives this a strong recommendation for minimising severe OHSS.
- Freezing all embryos to reduce late-onset OHSS, which is the form driven by an early pregnancy.
- Dopamine agonists (cabergoline is the one patients usually hear about) to reduce early OHSS, particularly where an hCG trigger has been used.
- Preferring an agonist trigger over "coasting", the older practice of pausing stimulation drugs for a few days to let estradiol fall.
ASRM's patient fact sheet lists a similar toolkit: lower stimulation doses, a leuprolide (GnRH agonist) trigger, cabergoline, and freezing eggs or embryos to delay pregnancy. If your clinic changed your trigger at the last minute or told you your transfer will happen in a later cycle, this is usually why. It can feel like a setback. Clinically it is a safety decision, and frozen transfers are a well-established route to pregnancy.
Questions worth asking on trigger day
- Which trigger am I getting, and why that one?
- Are we doing a fresh transfer or freezing everything?
- Will I be taking anything (such as cabergoline) after retrieval to reduce OHSS risk?
- Who do I call after hours, and what symptoms should make me call?
The first week after retrieval: a home-care routine
Your clinic's written instructions come first. Within those, a few habits make it easier to notice if things are drifting in the wrong direction.
Track a few simple things
- Weight, once a day, same time, same scale. The three-pounds-in-two-days threshold in ASRM's list only helps if you know your starting point.
- Fluids in and urine out. You do not need a measuring jug, but notice if you are drinking but rarely needing to urinate.
- Waist feel. If clothes that fit after retrieval suddenly will not close two days later, mention it.
- Breathing. Breathlessness lying flat or on stairs is a call-now symptom, not a wait-and-see one.
What usually helps with mild symptoms
ASRM describes outpatient care for OHSS as reduced activity, fluids with electrolytes, medication for nausea and pain, and frequent checks with ultrasound and bloodwork. Ask your clinic which pain relievers are acceptable for you; do not assume. Avoid strenuous exercise and anything that jolts the abdomen while your ovaries are enlarged, since enlarged ovaries are more vulnerable.
One detail surprises patients: ASRM notes that a standard pelvic exam is generally not recommended when OHSS is present, because pressure on the enlarged ovaries can rupture cysts. If you end up being seen somewhere other than your fertility clinic, such as an emergency department while travelling, tell them you have just had IVF egg retrieval.
If OHSS needs treatment
Most cases are managed without admission. When fluid build-up causes significant discomfort or breathing trouble, a doctor can drain it with a needle (paracentesis), which ASRM says brings significant relief in most cases, though it is sometimes repeated. Cabergoline may also be used to limit fluid accumulation. Hospital care is reserved for severe OHSS or when outpatient management is not working, and may involve intravenous fluids and further drainage.
The serious risks are dehydration, high pressure inside the abdomen, and blood clots. That is why leg swelling, chest symptoms and very low urine output sit on the urgent list.
Planning around OHSS when you have travelled for IVF
If you are having treatment away from home, OHSS is the main reason not to book the flight home for the morning after retrieval. Nothing here is a rule your clinic must follow, but these are reasonable things to settle before you travel:
- Ask about your risk in writing. If your AMH or follicle count suggests a high response, ask the clinic how long it wants you nearby after retrieval.
- Build slack into your return date. A flexible ticket is cheaper than rebooking under pressure while unwell.
- Know the after-hours route. Get the clinic's emergency contact and the name of the hospital it uses. Save both in your phone.
- Carry a one-page summary. Date of retrieval, number of eggs collected, trigger type, medications you are on. Any doctor seeing you will need these.
- Check your insurance wording. Many travel policies treat planned medical procedures and their complications differently. Our guide to travel insurance and complications abroad covers what to look for.
Long flights while you have significant OHSS symptoms are a conversation to have with your doctor, not a decision to make alone, because immobility and dehydration both work against you.
What OHSS means for the rest of your cycle
A diagnosis of OHSS does not mean your eggs or embryos are worse. It means your ovaries responded strongly. If your clinic switched to a freeze-all plan, your embryos are waiting in storage for a calmer transfer cycle, usually once your ovaries have settled and your period has returned. That transfer will follow its own preparation plan, covered in our guide to natural versus medicated frozen transfers.
If you had OHSS in a previous cycle, tell any new clinic. It is one of the most useful pieces of history you can give them, because it changes how they will dose and trigger you next time.
The short version
Bloating after retrieval is common and usually fades. OHSS is the same process taken further, and it is mostly preventable through dosing, trigger choice and freezing embryos instead of transferring. Know the call-now symptoms, weigh yourself daily for the first week, keep fluids up, and do not let a booked flight or a fear of bothering the nurse stop you from calling.
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