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One of the greatest advances in reproductive medicine has been the introduction of assisted reproductive technology, or ART. With treatments like intrauterine insemination (IUI) and in vitro fertilization (IVF), you have a better chance of clearing hurdles along the path to pregnancy.
If you’re using the modern marvels of medicine to conceive at a fertility clinic, you might already know that your specific plan informs the type of sperm you use. But is there a significant difference between different types? Does the type you use impact treatment outcomes? Consider this article a quick primer on sperm and fertility treatment.
Here’s the TL;DR of what you’ll learn before we get into it:
- If you’re working with a fertility clinic to undergo assisted reproductive technology (ART), IUI or IVF, you’ll be using fresh sperm that’s been washed and processed.
- If you’re trying to conceive with a partner or non-identified donor whose sperm has been cryopreserved, you’ll be working with frozen and thawed sperm.
- While the (limited) research examining ART success rates using fresh versus frozen sperm shows that there might be an increase in positive outcomes using fresh over frozen sperm in IUI, most fertility clinics say that both sperm types are fine for ART as long as sperm parameters are relatively “normal.”
- The factors that are most likely to impact ART success rates don’t have to do with sperm type (like age, which also plays a key role in chances of conception without treatment).
The basics: What are the different types of sperm used in fertility treatment?
The type of sperm you use isn’t exactly up to a personal choice, other than choosing between a non-identified (“anonymous”) or directed (“known”) donor if you don’t have a partner who produces sperm. The decision boils down to who’s providing the sample and what you’re doing with it.
“The main reasons someone will use frozen sperm is when the partner is not available the day of the egg retrieval, has severe male factor infertility, and we are needing to retrieve sperm from the testicles or they are using donor sperm,” explains reproductive endocrinologist and Modern Fertility medical advisor Dr. Temeka Zore, MD, FACOG. “Otherwise, we typically use fresh sperm.”
Here’s what to know about “fresh” versus frozen sperm:
1. “Fresh” washed/processed sperm: What you’d be working with if you undergo IVF or IUI with a partner who produces sperm:
- Any sperm sample that’s used at a fertility clinic will be washed and processed to remove chemicals that might cause adverse reactions in the uterus, as well as check movement (motility) and concentration (the number of sperm per unit volume of semen).
- The process involves separating the sperm from the seminal fluid (aka the ejaculate) so you get a concentrated amount of healthy sperm, and that washed sperm is placed in a protective liquid.
2. Frozen and thawed sperm: What you’d be working with if you’re trying to conceive with a person — a partner or a donor — whose sperm has gone through cryopreservation (e.g., a person might opt to freeze their sperm before beginning cancer treatment in order to preserve post-treatment fertility):
- This type of sperm will have been washed and processed before being frozen and stored in a freezer where it can be kept indefinitely.
- When the frozen sample is ready to be used, the sample will be thawed until it reaches room temperature, and then analyzed again after thawing to make sure there are still viable and healthy sperm remaining in the sample.
If you’re undergoing ART at a clinic, insemination will be timed as closely to ovulation as possible regardless of what sperm type you’re using for better odds of sperm meeting up with an egg. (Doctors recommend trying to conceive through sex every 1-2 days during the fertile window, or the five days leading up to and the day of ovulation, because sperm can live in the reproductive tract for up to five days.)
Does the type of sperm you use impact treatment outcomes?
According to Dr. Zore, there just aren’t many quality comparative studies looking into the topic of fresh versus frozen sperm in fertility treatment. Why? Because, as she explained earlier in this article, people typically opt for fresh sperm when they can. Below, we’re sharing what research we do have — and the factors that matter a lot more for treatment outcomes.
Fresh vs. frozen sperm and IUI success rates
IUI is a process that places the sperm directly into the uterus, so it has a shorter distance to go, bypassing the cervix and making it more likely that the sperm will encounter the egg.
In one 2018 study that reviewed 566 IUI cycles for people with ovaries who were diagnosed with unexplained infertility, researchers found that fresh sperm led to a significantly higher live birth and pregnancy rates when compared to frozen sperm for IUI using ovulation-inducing medications. That said, this study didn’t control for age (or individual drug protocols) — which, as we’ll explain in a sec, is a major factor in IUI success. (Other commonly cited studies are really old and less reflective of modern-day practices.)
Research aside, most fertility clinics say that either fresh or frozen sperm is totally fine to use in IUI and can lead to success. But the factors that likely matter more for IUI have nothing to do with what kind of sperm is used:
- Age (some data suggests that IUI per-cycle success rates are below 1% for people 44 and older)
- Male infertility and sperm-related factors (e.g., low sperm count and sperm motility, a high percent of sperm with abnormal morphology, a high percentage of sperm with DNA damage)
- Fallopian tube anatomy (blockage)
- Conditions like endometriosis (where tissue that’s similar to the uterine lining is discovered outside the uterus)
Fresh vs. frozen sperm and IVF success rates
In an IVF cycle, the ovaries are stimulated with fertility medications in order to grow multiple follicles and mature the egg inside each follicle, followed by egg retrieval (the same process that kicks off egg freezing). Then, sperm and eggs are combined in a lab followed by embryo transfer(s) into the uterus — where embryos ideally implant into the uterine lining and develop into a pregnancy.
When it comes to research around fresh versus frozen donor sperm in IVF, we did find one decent study — but it’s from the ’80s and difficult to access in its entirety. Caveats aside, the abstract suggests you can use frozen sperm without lowering the percentage of success by a statistically significant degree.
Other factors that may impact IVF outcomes more include:
- Age of the egg and sperm providers
- The clinic where IVF is performed (different ones may have different clinical outcomes and success rates)
- Ovarian reserve (how many eggs are available for retrieval)
The bottom line
The sperm you use when trying to get pregnant through fertility treatment largely depends on your plan and whether you’re using sperm from a partner, a directed donor, or a non-identified donor. Most fertility specialists say that any sperm type is fine if the partner or donor has relatively “normal” sperm parameters. Other factors, like age, matter a lot more for your success rates than the sperm type you’re using.
This article was medically reviewed by Dr. Temeka Zore, MD, FACOG, a fellowship-trained reproductive endocrinologist and infertility specialist and board-certified OB-GYN at Spring Fertility in San Francisco.