IVF Injections Explained: Types, Schedule and Possible Side Effects

IVF injections are the hormone medications used to stimulate your ovaries, prevent premature ovulation, trigger egg maturation, and support the uterine lining after embryo transfer. A typical cycle involves two to four different types of IVF injections over a period of 10 to 14 days, with most administered as small subcutaneous injections into the stomach or thigh.

This article walks through every type of IVF medication used during a cycle, explains the daily IVF injection schedule for both long and short protocols, covers side effects and how to manage them, and answers the questions patients most commonly ask. If you are preparing for IVF and want to understand what your cycle will involve, book a free advisory call with IVF Matters to talk it through with a fertility specialist.

Why Are Fertility Injections Needed?

In a natural menstrual cycle, your body produces enough follicle-stimulating hormone (FSH) to develop one mature egg per month. IVF requires multiple mature eggs to maximise the chance of producing viable embryos, so fertility injections supply extra FSH to stimulate the ovaries to produce several follicles at once.

Without these IVF hormone injections, you would have only one egg to work with, which significantly reduces the chances of a successful cycle. The medications also prevent your body from ovulating before the eggs can be collected, and they prepare the uterine lining for embryo implantation.

At IVF Matters, the fixed-price treatment package (£12,000) includes all IVF medication. This covers stimulation drugs, growth hormone, luteal support, and all monitoring blood tests and scans, so you won't have unexpected pharmacy bills during your cycle.

Types of IVF Injections: What Each One Does

1. Ovarian Stimulation Injections (FSH/HMG)

These are the core IVF injections. They contain follicle-stimulating hormone, either on its own (recombinant FSH) or combined with luteinising hormone (HMG). Common brand names include Gonal-F, Menopur, Bemfola, Ovaleap, and Meriofert.

You inject these daily, usually in the evening, for 10 to 14 days. They stimulate the ovaries to develop multiple follicles, each containing an egg. Monitoring scans (typically on day 6 and day 10 of stimulation) track how many follicles are growing and how large they are. Your consultant may adjust the dose based on your response (Guy's and St Thomas' NHS).

2. Down-Regulation Injections (GnRH Agonists)

Used in the long protocol, these switch off the pituitary gland's natural hormone production to prevent ovulation before egg collection. Common forms include buserelin (Suprefact) as a daily injection and nafarelin (Synarel) as a nasal spray. Prostap is given as a single injection, repeated once after one month.

Down-regulation starts on day 21 of the cycle before your IVF cycle and continues for 2 to 3 weeks before stimulation injections begin. You continue it alongside stimulation until two nights before egg collection.

3. Antagonist Injections (GnRH Antagonists)

Used in the short protocol as an alternative to down-regulation. Common brand names include Cetrotide and Fyremadel. Rather than switching off hormones in advance, antagonist injections are added from around day 5 or 6 of stimulation to prevent premature ovulation while stimulation continues.

The short protocol is often preferred for women with low ovarian reserve, those at higher risk of ovarian hyperstimulation syndrome (OHSS), or where a faster start to treatment is preferred (Gateshead Health NHS, IVF Booklet).

4. Trigger Injection (hCG or GnRH Agonist Trigger)

The trigger injection is a single, precisely timed injection that matures the eggs and prepares them for collection. It is given exactly 36 to 38 hours before the scheduled egg collection procedure. Timing is critical: if the trigger is given too early or too late, ovulation may occur before the eggs can be retrieved, or the eggs may not be mature enough.

The most common trigger is human chorionic gonadotropin (hCG), sold under brand names like Gonasi, Ovitrelle, and Pregnyl. In some cases, particularly where OHSS risk is high, a GnRH agonist trigger (such as buserelin) is used instead.

5. Progesterone Support (Luteal Phase)

After egg collection and embryo transfer, progesterone keeps the uterine lining thick and receptive for implantation. This is administered as pessaries (Cyclogest, Utrogestan), vaginal gel (Crinone), or in some cases intramuscular injection. Progesterone support continues until the pregnancy test, and if the test is positive, it typically continues until 8 to 12 weeks of pregnancy.

IVF Injection Schedule: Long Protocol vs Short Protocol

The table below shows a typical IVF injection schedule for each protocol.

Side Effects of IVF Injections

Common Side Effects During Down-Regulation

Because down-regulation temporarily suppresses estrogen, symptoms can resemble early menopause:

1. Hot flushes and night sweats

2. Headaches

3. Mood swings and irritability

4. Poor concentration

5. Fatigue

These symptoms improve once stimulation injections begin, because FSH causes estrogen levels to rise again.

Common Side Effects During Stimulation

1. Bloating and abdominal discomfort as the ovaries enlarge

2. Breast tenderness

3. Nausea

4. Bruising at the injection site

5. Heightened emotional sensitivity

Ovarian Hyperstimulation Syndrome (OHSS)

OHSS occurs when the ovaries over-respond to stimulation drugs. Mild OHSS (bloating, nausea, mild abdominal pain) affects a proportion of women undergoing IVF. Severe OHSS, which can involve significant fluid retention, difficulty breathing, and an increased risk of blood clots, is rare and occurs in about 2% of cycles.

Women with polycystic ovary syndrome (PCOS) are at higher risk. Monitoring scans and blood tests during your cycle help identify early signs of over-response, allowing your consultant to adjust medication or, in some cases, convert to a freeze-all cycle to prevent OHSS from worsening.

At IVF Matters, Dr Koita monitors each cycle personally, adjusting stimulation doses based on scan results to minimize the risk of over-response while maintaining the best possible egg yield.

Tips for Managing IVF Injections at Home

Injecting yourself at home can feel intimidating at first. These practical steps make it easier:

1. Ice the injection site beforehand. Numbing the area with an ice pack for 30 to 60 seconds reduces any sting.

2. Rotate injection sites. Alternate between left and right sides of your abdomen (or thighs) to minimize bruising and tenderness.

3. Inject at the same time each day. Consistency helps maintain steady hormone levels and makes the routine easier to stick to.

4. Prepare everything before you start. Lay out the medication, alcohol swab, and sharps bin so you can focus on the injection itself.

5. Let the medication reach room temperature. Cold injections can sting more. Take the vial out of the fridge 15 to 20 minutes before injecting.

6. Pinch a fold of skin. Insert the needle at a 90-degree angle into a pinched fold of skin on the stomach or thigh.

Your clinic will teach you (or your partner) how to prepare and administer each injection before your cycle begins. At IVF Matters, the nursing team provides a hands-on demonstration and a personalised written medication plan, so you know exactly what to inject, when, and how much.

IVF Medication: What Is Included in Your Treatment Package?

One of the most common sources of unexpected cost in IVF treatment is medication. At many clinics, the headline IVF price excludes stimulation drugs, and the pharmacy bill can add £1,500 to £3,000 on top of the quoted cycle cost.

At IVF Matters, the fixed-price IVF package (£12,000) includes all IVF medication: stimulation hormones, growth hormone, down-regulation or antagonist drugs, trigger injection, progesterone support, and all monitoring scans and blood tests. There is no separate pharmacy charge and no mid-cycle add-on cost.

If affordability is a concern, we offer flexible payment plans, including interest-free finance over 12 months.

FAQs on IVF Injections

Are IVF Injections Painful?

Most patients describe IVF injections as a small sting or pinch rather than real pain. The needles are very fine (similar to insulin needles) and are injected just under the skin, not into muscle. The first injection often feels more daunting than it is. Icing the area beforehand and injecting at room temperature both help reduce discomfort.

How Many Injections Will I Need in Total?

This depends on your protocol and how long your stimulation phase lasts. A rough estimate for a short protocol cycle is 10 to 16 daily stimulation injections, plus 5 to 8 antagonist injections and 1 trigger injection, totaling approximately 16 to 25 injections over the stimulation phase. Long protocol cycles involve additional down-regulation injections over 2 to 3 weeks before stimulation begins.

Can My Partner Give Me the Injections?

Yes. Many couples find it helpful for a partner to administer the injections, particularly for the first few days. Your clinic will teach both of you the technique during the pre-cycle nursing appointment.

What Happens if I Miss an Injection or Take It at the Wrong Time?

If you miss a dose or take it more than a few hours late, contact your clinic immediately for advice. Do not double the dose. For stimulation injections, a delay of an hour or two is unlikely to cause a problem, but the trigger injection timing is critical and must not be missed or delayed.

Do IVF Injections Cause Weight Gain?

Temporary bloating and water retention during stimulation are common and can feel like weight gain, but this typically resolves within one to two weeks after egg collection. The hormones themselves do not cause lasting weight gain. Maintaining a balanced diet and staying hydrated during stimulation helps manage bloating.

Take the Next Step

If you are preparing for IVF and want to understand exactly what your treatment will involve, book a free advisory call with IVF Matters. You can also visit the IVF treatment page for a full overview of the process, pricing, and what is included.

Resources

• Guy's and St Thomas' NHS — IVF Step 1: Medicines to Produce Eggs — NHS trust patient guide covering IVF medication protocols and side effects

• Gateshead Health NHS — IVF Booklet — Comprehensive NHS IVF patient information booklet covering all treatment stages

Explore More

• IVF Matters — IVF Treatment in London — How IVF works at IVF Matters, including the step-by-step process and what is included

• IVF Matters — Treatment Prices — Fixed-price packages for IVF, IUI, egg freezing, and all fertility treatments

• IVF Matters — Fertility Finance — Interest-free and flexible payment plan options