In vitro fertilization (IVF) provides an effective solution for couples facing fertility challenges, including those related to male factor infertility. One of the crucial determinants of IVF success is sperm count, but sperm quality—beyond just count—plays a significant role in the treatment’s effectiveness. Here’s an in-depth look at sperm count and quality parameters that influence IVF outcomes.
Sperm Count Basics
Sperm count, or sperm concentration, is measured in a semen sample and is a fundamental parameter in assessing male fertility. According to the World Health Organization (WHO) guidelines, a normal sperm count is 15 million sperm per millilitre of semen or higher. Counts below this threshold are categorized as low, with varying degrees of severity:
Other Factors Affecting Sperm Quality
Beyond sperm count, several factors impact sperm quality, which is crucial for successful fertilization:
Variability in Results
Sperm analysis results can vary based on factors such as age, health history, and the laboratory performing the tests. Variations in test results may not necessarily indicate a problem, so it’s essential to discuss findings with a healthcare provider to understand their implications and determine the appropriate next steps.
In IVF, both sperm count and quality are vital to achieving successful outcomes. While sperm count provides a foundational measure of fertility, factors like motility, morphology, volume, and viability are equally important in assessing the potential for successful fertilization. Understanding these parameters and their reference levels can guide appropriate treatment options and interventions, helping couples navigate their fertility journey with informed expectations and strategies.
There’s no definitive “lowest” sperm count for IVF. While a higher sperm count generally increases the chances of success, IVF techniques, such as Intracytoplasmic Sperm Injection (ICSI), can be effective even with very low sperm counts.
ICSI involves directly injecting a single sperm into an egg, bypassing the need for many sperm to compete for fertilization. This makes it possible to achieve successful pregnancies with as few as one or two sperm.
However, it’s important to note that other factors besides sperm count, such as sperm motility (movement) and morphology (shape), can also influence fertility. Also, DNA fragmentation & oxidation can affect the chances of success. We do have special sperm selection techniques that might help with these (Zymot, MACS).
Even in cases of azoospermia, especially if that is obstructive, we might be able to proceed with IVF together with TESE. That means finding sperm inside the testicles.
If we are going for the IVF procedure, we would like to see at least 15 million sperm per ml and of course, other factors beside the count also matter, for example, if we have 15 million sperm but we have a lot of dead sperm or abnormal sperm, this can impact our decision. So it’s a collection of different parameters that are seen in the sperm that makes an embryologist decide whether to proceed with an IVF procedure or whether to then change it to what we call ICSI or micro injection. ICSI has revolutionized our treatment in the lab for the infertile couples, the reason is for every egg we just need one good sperm to be found where the embryologist can pick it up and inject the egg with it and hopefully get fertilization and a good quality embryo.
Low sperm and very low sperms are our biggest challenges. There is not a cut-off as long as we find enough motile spermatozoa of good morphology to fertilize with the use of micromanipulation, we can proceed. Only in cases where no spermatozoa or not enough spermatozoa or non-spermatozoa of good morphology or motility are retrieved, we may stop the procedure. So, normally, what we do is before the onset of the stimulation regime, we check the sperm and we make sure that we do have enough spermatozoa for fertilization and if this is not the case, if we retrieve very small tiny numbers of spermatozoa, then we may advise the couple to accumulate two or three sperm samples with the use of a sperm cryopreservation in an effort to increase the number of available spermatozoa on the day of egg retrieval. So, on the day of the egg retrieval we may ask for one or two fresh samples and if these are not enough we may thaw the cryo stored samples. So, the higher the number of spermatozoa we have, the better selection we will do and the higher chances for a pregnancy we will have. If despite the efforts for accumulating spermatozoa we still don’t have sperm samples frozen, then the risk of not finding enough spermatozoa on the day of the egg retrieval is very high. In these cases, we may advise the couple to proceed to either a testicular biopsy – in order to have enough spermatozoa from the testicles, if if not enough spermatozoa are present in the ejaculate or to take the option of fertilizing as many oocytes as spermatozoa good spermatozoa are available while cryopreserving the oocytes for the ones that we don’t have enough spermatozoa. Both options are good – depending on the case and the overall history of the couple.
All clinics in the UK at least participate in external quality control so someone sends out images of sperm and we see whether they’re normal or not and then, all the census results are pulled just to make sure that we’re sort of consistent between clinics. The World Health Organization published numbers based on analysis, previous analysis which suggests normal ranges for sperm concentrations, sperm motility and sperm morphology and so anyone with 4% or more would be considered a normal morphology. Someone with 3% morphology, might class low and a clinic might say you need ICSI because your morphology is only 3%. Having said that, if your sperm count is 100 million and your morphology is 3%, that’s still a lot of normal sperm – certainly compared to someone who may have 20 million sperm but 4% morphology. So they would be considered suitable for IVF but your 100 million with 3% wouldn’t be. So morphology well assessment and treatment plan will vary clinic to clinic. I don’t personally believe in morphology assessment in an IVF cycle as long as we can see some normal sperm, then we’re happy to go with IVF whereas some clinics will recommend that you do ICSI because of global morphology and again it will vary between clinic and what their practice is.
In essence you just need one moving sperm to make a baby. Certainly micro TESE we’ve had that so, sample was to show one moving sperm the lab, probably wouldn’t be very happy about treating you because although there’s a big difference from the patient’s point of view between one moving sperm and no moving sperms, from the laboratory’s point of view, from a scientific point of view, there isn’t much difference because sperm quality can change a little bit, so if they were to come back with your treatment and have no sperm at the end of the treatment. So we did like a little bit more than that consistently to recommend that they’re happy enough to go ahead with treatment but in essence, on the day, if you’ve got ideally enough moving sperm so that each egg recovered has a sperm and to be injected into it, that’s all you really need.
The number count of sperm that we will need for fertilisation it will depend on the fertilisation technique that we will use. We have two different kinds of fertilisation technique we have natural IVF or ICSI in case of natural IVF, we usually recommend to have at least 4 million per milliliter of motile sperm. In case of ICSI, we do not have a minimum count number because we can perform ICSI even in testicular biopsy sperm when the number of sperm is lower than 100 000 sperms.
As long as we have one sperm per egg, that’s enough to go ahead with the IVF. The prognosis may not be very good because these severe male factors tend to have a lot of problems afterwards, but we can even do a surgical removal of sperm from the testicles, so even in cases of azoospermia, in which the patients may not produce a single sperm, IVF can be done.
Sometimes it’s being discussed if ICSI is always needed or if the sperm is good enough, you can carry out a conventional IVF in which you place the egg along with 100,000 sperm just to let them fertilize the egg. We do ICSI in 100% of our cycles. When you do conventional IVF, you are assuming a risk of having a low fertilization rate or even a complete fertilization failure, and we think that these procedures are too expensive. The cost is really high, and we feel that if we do ICSI, we save like 5% of cases in which you were going to have a fertilization issue that later would have been solved using ICSI. For us, it does not make sense to do that. When you do ICSI, as long as I said at the beginning, as long as you can have any motile sperm, and you can pick it up, you can inject that sperm into the egg and go ahead with IVF, so in almost all cases.
