IMSI (Intracytoplasmic Morphologically Selected Sperm Injection)

Intracytoplasmic morphologically selected sperm injection (IMSI) is a variation of ICSI that we use to aid the sperm selection for fertilisation. This technique uses an even higher power magnification to visualise inside the sperm, allowing our specialists to pick the sperm with the highest chance of achieving a successful fertilisation.




How does IMSI work?

IMSI uses a high-power light microscope, enhanced by digital imaging, to magnify a sperm sample more than 6,000 times its normal size. This enables the embryologist to detect problems and subtle structural alterations that a normal microscope cannot see. The embryologist then selects the sperm with the most normally shaped nuclei and highest level of motility.



Is IMSI for me?

There is some evidence to suggest that the use of high-magnification sperm selection may be associated with higher pregnancy and lower miscarriage rates and decreased risk of major birth defects1-5. However, still to date, there is a lack of evidence from randomised controlled trials on the beneficial use of IMSI. Hence, the most relevant indications for IMSI still remain to be determined.

As the use of IMSI is not evidence based, the clinic will only offer it when your consultant deems it appropriate for your treatment.

The risks associated with the use of ICSI also apply to IMSI; there is no significant risks to the patient or embryo.

IMSI is categorised as an additional treatment option by the Human Fertilisation and Embryology Authority (HFEA) and has currently been deemed as ‘red’ in the HFEA traffic light system. Red-rated add-ons are considered by the HFEA experimental in nature.

Please refer to the treatment add-ons page of the HFEA website at

If you would like to book an appointment with one of our doctors you can:

  • Speak to the booking team on +44 (0)20 7837 2905  (Mon – Fri 8.30am – 6pm)
  • Email us on 
  • Visit our Appointments page, fill out the contact form and a member of the team will be in touch


  1. Duran-Retamal M, Morris G, Achilli C, Gaunt M, Theodorou E, Saab W et al. Livebirth and miscarriage rate following intracytoplasmic morphologically selected sperm injection vs intracytoplasmic sperm injection: An updated systematic review and meta-analysis. Acta Obstet Gynecol Scand. 2020; 99: 24-33
  2. Blair B, Odia R, Lewis S, Khanjani S, Serhal P, Ben-Nagi J. Use of intracytoplasmic morphologically selected sperm injection (IMSI) reduced risk of miscarriage and increases embryo utilisation in patients with high sperm DNA fragmentation index (DFI). Abstract, BFS Edinburgh, January 2020.
  3. Cassuto N, Hazout A, Bouret D, Balet R, Larue L, Benifla L et al., Low birth defects by deselecting abnormal spermatozoa before ICSI. Reprod Biomed Online 2014; 28:47-53.
  4. Teixeira D, Miyague A, Barbosa M, Navarro P, Raine-Fenning N, Nastri C, Martins W. Regular ICSI versus ultra high magnification IMSI sperm selection for assisted reproduction. Cochrane Database Syst Rev. 2020; 2:CD010167.
  5. Klement A, Koren Morag N, Itsykson P, Berkovitz A. Intracytoplasmic morphologically selected sperm inection versus intracytoplasmic sperm injection: a step toward a clinical alogorithm. Fertil Steril; 2013: 99:1290-3.

IVF Packages With Access Fertility

IVF Packages With Access Fertility
CRGH is partnering with Access Fertility to offer a series of IVF programmes and packages. For more information please click below.

NHS Funding for Fertility Care

CRGH is an NHS approved centre and funding may be available for some patients. You will need to meet certain criteria and be referred to us by your GP. Please call or email us for further information.
Call: +44 (0)20 7837 2905

or click below:

Newsletter Sign Up

Upcoming Events

No event found!


CRGH patient leaflet
Download our Patient Guide