Although in vitro fertilisation is an infertility treatment that mainly involves procedures carried out on the female partner, it can be used to treat infertility in both sexes. Some men are not able to produce actively swimming sperm, or they may produce only very low numbers of sperm. Intracytoplasmic sperm injection can help in these cases, even if sperm retrieval is needed to remove sperm from inside the testes first.
As the name suggests, intracytoplasmic sperm injection is a delicate procedure that involves injection of a single sperm into the cytoplasm of the woman’s egg, bringing about fertilisation. Several eggs are treated with sperm and allowed to develop in culture fluid in carefully controlled conditions. The embryos that develop after 2–3 days, or blastocysts that develop within 5–6 days are then transferred to the woman’s uterus as in a standard IVF cycle.
Intracytoplasmic sperm injection can be very helpful in cases of male infertility due to severe sperm abnormality or when the male partner is disabled. It can also be useful for couples who are infertile because the man has had a vasectomy that cannot be reversed.
Couples experiencing the following infertility issues may benefit from intracytoplasmic sperm injection:
The most usual method is to use fresh ejaculate but this is not possible in all male partners contributing sperm for intracytoplasmic sperm injection. Rarely, surgical removal of sperm from the testes is required; it is also possible to collect sperm from the urine if the man experiences retrograde ejaculation (the sperm travel backwards into the bladder instead of forwards into the penis). Men who cannot ejaculate because of nerve injury may be able to do so with electro-ejaculation.
Couples having intracytoplasmic sperm injection go through a very similar procedure to those having in vitro fertilisation. The woman is first given a course of hormone treatment to stimulate her ovaries to produce several eggs. These are monitored using ultrasound and once mature egg follicles have formed, the eggs are collected using a thin tube passed through the vagina. The eggs are then placed in special culture fluid in the laboratory.
Sperm is collected on the same day, a little before egg collection, and then a single sperm is injected into a single egg. Intracytoplasmic sperm injection is repeated for all the eggs available and all are cultured to see if they develop into embryos. The best quality embryo at the 2–3 day stage, or the strongest blastocyst at the 5–6 day stage is then transferred into the woman’s uterus.
Different countries have different rules that state how many embryos can be transferred after IVF or ICSI; in the UK, it is likely to be 1–2 but other countries may allow more embryos, which means that the risk of a multiple pregnancy is increased.
The success rates for intracytoplasmic sperm injection are similar to those of IVF and vary with age and the stage at which the embryos are transferred. Blastocyst embryo transfer, at the 5–6 day stage, generally has higher success rates than embryo transfer at the 2–3 day stage.
The vast majority of children that are born as a result of intracytoplasmic sperm injection are healthy but there is a risk that if the father produces abnormal sperm, this may be due to a genetic trait that is passed on to the child. It may be possible to test for known genetic diseases using pre-implantation genetic screening (PGS) but if there is no obvious genetic abnormality, there is no test.
Intracytoplasmic sperm injection also carries the same risks as standard IVF, including a higher risk of a multiple pregnancy, an increased risk of ovary hyperstimulation in the female partner, and a higher risk of implantation in the fallopian tubes, resulting in an ectopic pregnancy.