IVF injections explained: what each one is for, and what to expect
IVF medicines come in four groups. Daily stimulation injections, such as HMG or recombinant FSH, help several eggs grow. A second daily injection stops the eggs being released too early. A single trigger injection completes their maturation before collection. Progesterone, as injections, capsules or tablets, then supports the womb lining. Every dose is set individually.
Watch on YouTube if the player does not load.
The list of medicine names on an IVF plan can look alarming. In this video Dr Mayur Pai opens the actual boxes and explains what each injection is for, in plain language. This guide follows the same order; if you are new to IVF, start with the IVF process explained step by step. It is an overview only: the exact medicines, doses and dates are always decided by your own doctor, and nothing here replaces the plan written for you.
Why does IVF need injections at all?
In a natural cycle the body grows one egg a month. IVF aims for several, because not every egg will be mature, fertilise or grow into a healthy embryo. The injections let the doctor grow a group of eggs in a controlled way, keep them in the ovary until they are ready, and then prepare the womb for the embryo. Each group of injections does one of these jobs.
1. Stimulation injections: growing several eggs
These are the main IVF injections, called gonadotropins. They carry the same hormones the brain sends to the ovaries every month, mainly FSH (follicle stimulating hormone), sometimes with LH. The common types are:
- HMG, which contains both FSH and LH and is widely used.
- Urinary FSH, a highly purified form of FSH.
- Recombinant FSH, made with DNA technology to a very high purity, and often chosen for women with polycystic ovaries.
Which one you are given, and how much, depends on your profile: your age, your weight, your egg reserve on the AMH test and scan, and whether you have PCOS. Stimulation usually runs for about eight to twelve days, sometimes longer. The first check scan is typically after about five days, and the plan is adjusted from what the follicles show. For a closer look at these medicines, read gonadotropin injections in IVF.
2. Injections that stop early ovulation
As several follicles grow, rising hormone levels can set off the body's own release signal, called the LH surge, before the doctor is ready to collect the eggs. If that happens, eggs can be lost or their quality affected. To prevent it, a second daily injection, called an antagonist, is added once the follicles reach a certain size, usually about halfway through stimulation.
It is given alongside the stimulation injection, at a separate site, and should be taken at the same time every day. Some treatment plans use a different medicine for the same purpose, started earlier; your doctor will tell you which plan you are on.
3. The trigger injection: the final step before egg collection
When scans show the lead follicles are mature, you are given the trigger. It completes the final maturation of the eggs so they can be collected. The most common trigger is hCG. For women with polycystic ovaries, or anyone at risk of over-stimulation, the doctor may choose a different type, called an agonist trigger, which lowers the risk of ovarian hyperstimulation syndrome (OHSS). Some plans combine both, as a "dual trigger". Why PCOS needs extra care during stimulation.
The trigger is the one injection where timing is everything. Egg collection is planned for about a day and a half later, so take it at exactly the time written on your plan.
4. Support after egg collection and transfer
After egg collection, progesterone is given to prepare and support the womb lining for the embryo. It comes as vaginal capsules, tablets or injections, and your doctor chooses the form that suits you. Take it daily, at the same time, and continue until the pregnancy test and beyond if you are advised to.
A few women are also advised other medicines, such as a blood-thinning injection, when the doctor feels they are needed. These are not routine and should never be started on your own. You can see where each injection falls in the calendar in the IVF timeline, week by week.
Pens, pre-filled syringes and vials: what to expect at home
Many IVF injections now come ready to use, in pre-filled syringes or pens, so there is nothing to mix. Others come as a powder with a liquid, and the nurse either prepares them or shows you how. Your first injection is usually given at the clinic, where the nurse shows you and your husband exactly what to do; after that, most couples manage the rest at home.
The needles are fine and short, and most injections go just under the skin of the tummy or thigh. A brief sting and the odd small bruise are normal. Change the site each day, store the medicines as instructed, and note the time of every dose.
Common side effects, and when to call
Mild bloating, a sense of fullness in the lower tummy, breast tenderness and mood swings are common while the follicles grow. Call us straight away if you have severe tummy pain or swelling, repeated vomiting, breathlessness, or you are passing much less urine than usual. These can be signs of over-stimulation, which needs prompt attention.
The same explanation in Konkani
Watch on YouTube if the player does not load.
Dr Mayur Pai also recorded this explanation in Konkani, for families more at home in it. It covers the same injections, what each is for, and roughly when in the cycle it is given.
About this guide
This guide is by Dr Mayur Pai, MBBS, MS (Obstetrics & Gynaecology), a fertility and laparoscopy specialist. Pai Hospital in Goa has its own operating theatre and its own IVF laboratory, so the scans, the egg collection, the laboratory work and the embryo transfer all happen in one place, under one team.
Questions, or ready to book?
Confused by the names on your IVF plan, or nervous about giving injections at home? Send your question and any reports on WhatsApp to +91 95185 02773. To book a consultation, call Sheetal at our fertility reception on +91 95459 20817; every visit is by appointment. Consultations are held in Panjim, Margao, Mapusa and Vasco. Our IVF packages are transparent and fixed; ask us and we will explain exactly what is included.
This article is for education only and is not personal medical advice; please consult your doctor about your own situation.
Your questions
How many days of injections does IVF need?
Stimulation injections usually run for about eight to twelve days, sometimes a little longer, depending on how the follicles grow. The injection that prevents early ovulation is added partway through, the trigger is a single injection at the end, and progesterone support follows egg collection.
What if I miss an injection or take it late?
Call the clinic straight away rather than doubling up or skipping on your own. For most stimulation injections the doctor will tell you how to adjust. A missed or late trigger, or a missed injection that prevents early ovulation, can change the whole plan, so it needs advice at once.
Do I need injections after the embryo transfer?
Often, but not always. Progesterone support continues after the transfer and can be given as injections, vaginal capsules or tablets; your doctor chooses the form. A few women are also advised a blood-thinning injection when the doctor feels it is needed.
Why must the trigger injection be taken at an exact time?
Because egg collection is planned for a set time after it, about a day and a half later. If the timing slips, the eggs may not be at the right stage when they are collected, so take it at exactly the time written on your plan.
Can the doctor change my injections during the cycle?
Yes. The plan is adjusted from your scans and, sometimes, blood tests. If the follicles grow slowly, or too many grow at once, the doctor may change the medicine or the amount, so always follow the latest instructions you are given.
Or call +91 95185 02773
This page is for general education and is not personal medical advice. Treatment depends on your own examination and reports, so please speak to a doctor about your situation. We do not carry out or offer sex determination of any kind.