IVF or IUI: how the two treatments differ and how to choose

IUI and IVF are the two treatments most couples hear about first, and they are often presented as a ladder: try the simpler one, then move up. Sometimes that is right. Often it is not, because the two treatments suit different problems, and for some people the simpler one is not worth trying at all. This guide explains how the two differ, who each one is for, what a cycle of each involves, and where in India each can be done under the Assisted Reproductive Technology (Regulation) Act, 2021 and the rules made under it. It is written for patients and for the doctors who refer them. It publishes no success rates and no prices, because this directory holds neither for any clinic, and it is not clinical advice. Everything it refers to can be found from the directory home.

What each treatment is

IUI. The HFEA, the UK fertility regulator, defines it as “a type of fertility treatment in which the better quality sperm are separated from sperm that are sluggish, non moving or abnormally shaped. These sperm are then injected directly into the womb.” It can be done with a partner's sperm or with donor sperm, and with or without drugs to stimulate the ovaries. The IUI treatment page covers it in detail.

IVF. In the HFEA's words, “IVF is a type of fertility treatment where fertilisation takes place outside the body.” The ovaries are stimulated, the eggs are collected and fertilised in a laboratory, and an embryo is transferred to the womb. The IVF treatment page covers who it is offered to, and the guide to the IVF process walks through a cycle step by step.

The real difference

The difference is where fertilisation happens. The HFEA explains: “In IUI, the highest quality sperm are selected and injected into the uterus where they are left to fertilise the eggs naturally. In IVF, the eggs are removed from the body and fertilised in the lab.” Everything else follows from that. “This means that IUI is a less invasive procedure which involves fewer drugs than IVF.” It is also cheaper. But it leaves more to chance: “Once you've injected the sperm you're allowing the body's natural processes to take over whereas in IVF you have more control”, because in IVF the laboratory can see whether an egg has fertilised and choose which embryo to transfer.

The HFEA sums the trade-off up in one line: “IUI allows the body to do more on its own than IVF, so it's a more natural but also less successful form of treatment.” The comparison is a general one. Which treatment suits you depends on the cause of the problem, and that is decided by tests, not by preference.

Who IUI is for

IUI works when the main obstacle is getting good sperm to the egg, and the rest of the system works. The HFEA lists the people it is commonly used for. They include “People who need donated sperm but have no female fertility problems”, couples who “are unable (or would find it very difficult) to have vaginal intercourse, for example because of a physical disability or psychosexual problem”, and those who need specific help to conceive safely, such as men with HIV whose sperm has been washed. Where donor sperm is used in India, it comes from a registered ART bank; the sperm donation page and the guide to donor eggs and donor sperm explain the rules.

IUI is also offered for unexplained infertility. The HFEA notes that UK guidance from NICE advises against IUI with a partner's sperm in that situation, so it is worth asking a clinic why it is recommending IUI if no cause has been found.

Who IUI is not for

The HFEA is direct on this point: “It's important to understand that IUI is not a cheaper/less invasive alternative to IVF. If you have a significant fertility problem it's unlikely to work for you.” It lists the cases: “If you have blocked fallopian tubes, severe endometriosis, low quality eggs, a low number of eggs (low ovarian reserve), or male factor infertility, IUI will not be appropriate for you.” Age matters too. The HFEA says older women may be advised to have IVF even where IUI would otherwise be suitable, because “As women age the number of available eggs naturally decreases, as do your chances of succeeding with IUI.” The guide to age and fertility explains why.

Because IUI relies on the sperm reaching the egg inside the body, the tubes have to be open: “You can only have IUI if your fallopian tubes are open and healthy.” That is why tubal checks come before IUI, not after it fails.

Who IVF is for

The HFEA lists the people who might be recommended IVF. They include “Women with blocked or damaged fallopian tubes.”, “People with unexplained fertility problems, or who have tried other treatments that were unsuccessful.”, men with low sperm counts or many abnormal sperm, for whom ICSI may be added, women with ovulation problems that other treatments have not resolved, and “Older women who are less likely to be successful with less invasive treatments.” Where sperm quality is the problem, the laboratory can inject a single sperm into each egg; the ICSI page explains that variant.

Before either: drugs alone

For some people neither treatment is the first step. The HFEA notes: “Not everyone needs IVF. For example, some problems with ovulation may be corrected with drug treatment alone so it's important you understand all your options before going ahead.” Drugs that stimulate ovulation are often the first treatment where periods are irregular, and they are also used alongside IUI. They need supervision, because “There's a risk with Clomid of developing too many follicles (the sacs that hold your eggs).” The ovulation induction page describes that treatment.

What a cycle of IUI involves

An IUI cycle is short and mostly takes place around your own cycle. The HFEA outlines it. The tubes are checked first. Drugs may be used to boost egg production, or the cycle may be natural. If drugs are used, ultrasound scans follow to check how many follicles are developing. When the timing is right, a hormone injection may be given to trigger ovulation, or tests are used to detect it. Then comes the insemination itself, in which the prepared sperm are placed in the womb; “The whole process takes just a few minutes and is relatively pain free.” A pregnancy test follows on a set date.

What a cycle of IVF involves

An IVF cycle is longer and more involved. The HFEA says “For most people, one cycle of IVF will take between four and six weeks.” It includes stimulation with injections and monitoring, egg collection under sedation, fertilisation in the laboratory, several days of embryo culture, and a transfer. The guide to the IVF process describes each stage, and the treatments guide sets both treatments beside the others.

The risks compared

The biggest risk is the same for both. For IUI, the HFEA says “The main worry is that you might have a multiple pregnancy (twins, triplets or more), which carries serious health risks to both mother and babies.” With IUI the clinic cannot control how many eggs are fertilised, so the risk is managed by monitoring: “Your risk of multiple pregnancy will depend on how many follicles (and therefore how many eggs) develop.” If too many develop, “the cycle will have to be cancelled because of the risk of multiple pregnancy.”

In IVF the risk is managed by transferring fewer embryos. The Act sets a ceiling: “not more than three oocytes or embryos may be placed in the uterus of a woman during the treatment cycle”, and the HFEA recommends a single embryo for most women. IVF carries an extra risk from the stronger drugs, ovarian hyperstimulation syndrome, and the egg collection procedure itself. Among the rarer risks of both, the HFEA lists “infection, bleeding, and bowel perforation following IVF or IUI procedures (rare).”

Moving from IUI to IVF

If IUI is the right treatment, it may take more than one cycle, and the HFEA says “Many people have several cycles of IUI before they achieve a successful pregnancy so if there are no obvious problems with your fertility your doctor may recommend you try again.” If several cycles have not worked, further tests are usually done, and the HFEA notes that “Depending on the results you may be advised to consider IVF.” Agree in advance with the clinic how many IUI cycles you will try before reviewing the plan, so the decision is made on evidence rather than by default.

Where each can be done in India

This is where Indian law draws the line clearly. Under the ART Rules, a Level 1 clinic is one where “preliminary investigations are carried out including diagnosis of type, cause of infertility and only IUI is carried out as part of treatment.” A Level 2 clinic is one of the “ART clinics where all/advanced investigations, diagnostic and therapeutic procedures in ART are carried out.” So IUI can be done at either level, while IVF needs a Level 2 registration. If you start at a Level 1 clinic, ask which Level 2 laboratory it works with in case you need IVF later. The guide to clinic levels explains the registration.

Pages such as IUI in Mumbai, IUI in Madurai and IVF in Ahmedabad list the clinics in a city that name the treatment on their own website. That is the clinic's own statement, not a check of its laboratory. To see every registered clinic in a city, start from the clinics index or a city page such as Kolkata. Each clinic page shows the registration number recorded in the National ART & Surrogacy Registry extract, and the level where the extract records one; where it does not, the clinic's certificate is the authority. The fertility doctors index lets you look a doctor up by name, and the treatments index describes each treatment.

Questions to ask before choosing

• What do our test results show, and which of them points towards IUI or IVF?
• Have my tubes been checked, and with which test?
• If you recommend IUI, why, and will it be with drugs or in a natural cycle?
• How many IUI cycles would you try before reviewing the plan?
• How will you monitor the risk of a multiple pregnancy?
• Is the clinic registered at Level 1 or Level 2, and if Level 1, where would IVF be done?
• What does each cycle cost, itemised and in writing?

For doctors referring a patient

The choice between IUI and IVF is usually made on test results the referring doctor may already hold. Send the semen analysis, any tubal assessment and the ovulation tests with their dates, and note any previous cycles of ovulation induction or IUI. A patient referred for IUI whose tubes have not been checked, or whose partner's sperm has not been tested, will need those tests before anything else. Refer for IVF to a clinic whose laboratory is registered at Level 2.

Where this guide comes from

Statements about the law are quoted from the Assisted Reproductive Technology (Regulation) Act, 2021, and the description of clinic levels from the ART Rules, 2022. Descriptions of both treatments and their risks are quoted from the patient pages of the UK's Human Fertilisation and Embryology Authority (HFEA). Those pages also compare the two treatments with figures; this guide quotes none of them. Facts about clinics come from the National ART & Surrogacy Registry extract this directory holds and from each clinic's own website. Nothing in this guide is clinical advice, and nothing in it is sponsored.