IVF, IUI and ICSI: What is the Difference?


IVF, IUI and ICSI are various forms of infertility treatments or assisted reproductive techniques (ART). Unlike IVF, IUI does not always involve administration of fertility medication, hence considered a more ‘natural’ fertility treatment. ICSI is a modification of the standard IVF procedure undertaken in cases of severe male infertility.

This article provides simplified information which will help you understand the basic differences between the three:

IUI (Intrauterine Insemination)

IUI is a cost-effective fertility treatment in which healthy sperm retrieved from the male partner is manually planted inside a woman’s uterine cavity around the time of ovulation. For many patients seeking infertility treatment, non-medicated or natural cycle IUI is often the first recourse recommended by doctors. Placing the sperm directly into the uterus helps increase the chances of fertilization and may benefit a couple in cases where:

  • the woman has problems with ovulation or has polycystic ovaries
  • the woman has cervical mucus hostility – when the mucus or fluid produced by the woman’s cervix is thick and sticky, making it difficult for the sperm to reach the egg for fertilization
  • there is mild male-factor infertility
  • the male partner has problems with ejaculation
  • there is unexplained infertility – when the cause of infertility cannot be determined despite detailed investigation
  • for same-sex couples or single women who wish to use donor sperm to get pregnant

Performing IUI requires that the woman’s Fallopian tubes are healthy and free of any blockage which may be confirmed through a laparoscopy.  Some patients, for example women who have ovulation problems, may need to be given fertility medication to stimulate the ovaries. This is known as stimulated cycle IUI.

During an IUI, the menstrual cycle is closely monitored to ascertain the time of ovulation as the insemination must be done within 36-40 hours of ovulation. On the day of the IUI procedure, the male partner provides a semen sample from which motile or fast-moving sperm is extracted and prepared for insemination. The process of sperm injection takes about 10 minutes and is usually painless.

Thus, a standard IUI cycle, from ovulation induction to sperm implantation, involves the following steps:

  • Ovulation induction (only in Stimulated Cycle IUI)
  • Sperm retrieval and preparation
  • Insemination of sperm into the womb
  • Pregnancy test after two weeks

IVF (In vitro Fertilization)

IVF is essentially the process of facilitating fertilization of a female egg by a male sperm outside of the human body. Most IVF cycles involve fertilization of multiple eggs to improve chances of success.

A complete IVF cycle takes up to 4-6 weeks, beginning with ovarian stimulation wherein the female is given medication to promote the growth of egg containing follicles. Just like in an IUI cycle, the entire process – from ovarian stimulation to egg release – is closely supervised by the fertility doctor through ultrasounds, blood tests and medication.

Once ready for retrieval, mature eggs are removed from the ovaries and simultaneously a sperm sample is obtained from the male partner. This is followed by selection and preparation of the better quality egg and sperm for fertilization in a glass dish.

The dish is then placed in an incubator which provides an environment conducive to fertilization. Once fertilized, the embryo is allowed to grow for another 2-5 days. The embryo selected for transfer is then planted into the female’s uterus or Fallopian tube with the help of a thin tube called a catheter. Embryo transfer may be done either three or five days after fertilization. The extra embryos, if any, may be frozen for future use.

To summarize, a standard IVF cycle involves the following steps:

  • Ovarian stimulation
  • Egg retrieval and selection
  • Sperm retrieval and preparation
  • Fertilization
  • Embryo culture (embryo development)
  • Embryo transfer
  • Pregnancy test after two weeks of ET

ICSI (Intracytoplasmic Sperm Injection)

ICSI is a specialized form of in vitro fertilization and is one of the most frequently practiced treatments for severe male-factor infertility.

Unlike in IVF where the oocyte and the sperm are allowed to fertilize on their own, ICSI goes a step further wherein your embryologist injects a single high quality sperm into a mature female egg (oocyte). The procedure, also known as insemination, is usually performed for more than one oocyte.

The egg retrieval from the female and sperm collection from the male partner are usually done on the day of the procedure. If the male partner is unable to provide a fresh semen sample, sperm may be retrieved surgically from a testicle. Your embryologist then separates high-quality sperm, ‘washes’ or treats them for insemination and injects a single sperm into each egg. This is followed by embryo culture and embryo implantation as previously explained under IVF.

A complete ICSI cycle takes between 4 and 6 weeks. ICSI is particularly beneficial in the following situations:

  • severe male-factor infertility indicated by very low sperm count or nil sperm
  • when the male is producing healthy sperm but is unable to ejaculate due to a physical obstruction or erectile dysfunction
  • if the couple is unable to have sexual intercourse for biological or medical reasons, or
  • for couples using donor sperm

A typical ICSI cycle involves the following stages:

  • Ovarian stimulation
  • Egg retrieval and selection
  • Sperm retrieval and preparation
  • Sperm injection
  • Fertilization
  • Embryo culture
  • Embryo transfer
  • Pregnancy test after two weeks of ET

The success rates of ICSI are similar to those of IVF. ICSI is usually recommended to couples with severe male infertility; however some clinics prefer doing ICSI even when the male’s sperm count is normal. Selection of a fertility treatment method depends on a number of factors such as the age of the female partner, cause of female infertility, level and cause of male infertility, past ART history etc. Only when your fertility specialist has done a detailed analysis of your condition should they be able to recommend treatment options best suited for your case.

If you have more questions or need further guidance regarding selection of fertility treatment, feel free to consult Dr. Manika Khanna for a free second opinion.