Step 2: Egg collection

IVF treatment

The second step of IVF treatment is egg collection. This step usually takes about 20 minutes. 

Our team decides the best day for your egg collection. This decision is based on:

  • your medical history
  • your response to the medicines in step 1
  • the findings from your ultrasound scan

Before egg collection

Trigger injection

You have an injection late at night, 36 hours before the planned egg collection. This is called a trigger injection.

The time that you have the trigger injection is important and we give you clear information about this. If you have the trigger injection at the wrong time, your eggs will not be mature, will not be released and are unlikely to fertilise. 

You do not need to have any more injections after the trigger injection.

Eating and drinking

You should not eat or drink anything for 7 hours before your egg collection. This is because you are sedated for the procedure.

Sedation is a type of anaesthetic that helps you relax and stops pain during the procedure. It can sometimes make you feel sick. An empty stomach reduces the chances of complications if you are sick (vomit).

Before going to hospital

You should have a bath or shower on the morning of your egg collection.

Please do not wear makeup, nail varnish, perfume, jewellery or contact lenses.

Your partner or a responsible adult needs to come with you to hospital and take you home. 

Egg collection procedure

You might be asked to take pain medicine 1 hour before the procedure. This is in the form of a dissolvable medicine that is put into your bottom (suppository). Please speak to a nurse if you are concerned about this. 

When you arrive in the assisted conception unit (ACU), the nurses take you to the procedure and recovery area and ask you to change into a hospital gown. 

In the egg collection room, you are introduced to the team involved in the procedure. 

We put a small plastic tube (cannula) into a vein in your arm or hand. This tube is used to give you sedation medicine.

We give you oxygen to breathe and monitor your pulse, blood pressure and breathing during the egg collection. 

We put a small device called an ultrasound probe inside the vagina. A fine needle is attached to the side. We gently pass the needle through the wall of the vagina into the ovary. It collects fluid from a follicle (sac containing an egg). We move the needle from one follicle to the next until we have emptied all the follicles in the ovary.

We then remove the needle and repeat the procedure in the other ovary. 

Not every follicle contains an egg. Rarely, we do not find any eggs. Sometimes, despite draining a good number of follicles, we might get a low number of eggs. We tell you after the procedure how many eggs we have collected.

Recovering after the egg collection

After the procedure, you rest on a bed in the recovery area for 1 to 2 hours.

A responsible adult should take you home by car or taxi. We do not recommend public transport. This is particularly important if your partner had a procedure to collect sperm on the same day. They also had sedation for their procedure.

Sedation can temporarily affect your reasoning, reflexes, judgement, coordination and skill. 

Side effects

You might get some lower tummy or pelvic pain after the procedure. It's safe to take paracetamol for this.

You might have some blood-stained fluid (discharge) from the vagina. This should become darker and stop after a few days. The blood comes from where we passed the needle through the wall of the vagina. 

Taking progesterone

We prescribe the hormone progesterone for you to take for 17 days after the egg collection. This helps to prepare the lining of your womb for pregnancy. We explain how to take progesterone before you go home on the day of your egg collection.

If your egg collection is cancelled

About 5% of cycles have to be cancelled before the egg collection. This is usually because the medicines to prepare your body have not worked as we hoped. It is possible that not enough follicles have developed in your ovaries, or you might have produced too many follicles.

If you have too many follicles, you are at risk of ovarian hyperstimulation syndrome (OHSS). This is a rare complication of IVF. You develop too many eggs in the ovaries and they become very large and painful. The condition is made worse if you get pregnant. 

If you release a large number of eggs at once after a cycle cancellation, there's a risk of having triplets or a higher number of pregnancies. The more babies that you carry, the greater the chance of miscarriage or other problems. You should use a condom to prevent pregnancy in the days that follow until you have a period. 

If your cycle is cancelled, we ask you to stop taking all of the medicines. We arrange a follow-up appointment with a senior doctor as soon as we can. At this appointment, we assess your treatment again. We also plan another IVF treatment cycle, if appropriate. 

We realise that it is disappointing to have a cycle cancelled. You can speak with one of our fertility counsellors for support.

If your cycle is cancelled, this does not mean that you will never respond well to IVF treatment. Every cycle is different and we might be able to adjust your treatment. This might improve your response to IVF and chance of getting pregnant in a future treatment cycle.

Resource number: 2687/VER4
Last reviewed: July 2023
Next review: July 2026

Trusted Information Creator. Patient Information Forum

Contact us

If you have any questions about IVF, please contact our assisted conception unit (ACU).

Phone: 020 7188 2300

Email: [email protected]

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

Is this health information page useful?