What Is the PESA Procedure for Sperm Retrieval?

Percutaneous epididymal sperm aspiration, or PESA, is a minimally invasive procedure used to collect sperm directly from the epididymis in men who have no sperm in their ejaculate due to a physical blockage. It is one of several sperm retrieval techniques developed for use alongside in vitro fertilization, and it stands out for being quick, performed under local anesthesia, and requiring no surgical incision. The procedure has become a mainstay in fertility treatment for obstructive azoospermia, though its success depends on several factors that are worth understanding before you or your partner go through it.

Who Needs PESA and Why

PESA is designed for men with obstructive azoospermia, a condition where the testes produce sperm normally but a blockage somewhere along the reproductive tract prevents sperm from reaching the ejaculate. The most common causes include prior vasectomy, infection-related scarring, and congenital bilateral absence of the vas deferens (CBAVD), a condition where the tubes that carry sperm from the epididymis simply never formed. CBAVD is linked to cystic fibrosis gene mutations and cannot be corrected surgically, making sperm retrieval the only route to biological fatherhood for these men.

Before scheduling PESA, your doctor will confirm that the problem is actually a blockage rather than a production issue. The key lab tests are a morning testosterone level and follicle-stimulating hormone (FSH). An FSH below 2 or above 6 may signal that sperm production itself is compromised, which would require further workup before any retrieval attempt makes sense.¹ In men with confirmed obstructive azoospermia, the testes are typically normal in size and function, meaning there is a healthy supply of sperm sitting in the epididymis waiting to be accessed.

How the Procedure Works

PESA can be done in a clinic or office setting without general anesthesia. A spermatic cord block is performed first: the doctor injects a local anesthetic along the spermatic cord near the groin, numbing the entire scrotal area.² Oral sedation may be added for comfort, but full sedation or general anesthesia is usually unnecessary.³

Once the area is numb, the doctor uses a fine butterfly needle, typically 21- or 23-gauge, attached to a syringe primed with a small amount of sperm wash medium. The needle is passed through the scrotal skin into the head of the epididymis while suction is applied. The doctor holds the epididymis in position between the thumb and index finger, guiding the needle into the coiled tube where mature sperm are stored. Fluid containing sperm is drawn into the syringe. The entire aspiration often takes just a few minutes, and the sample is handed off to the embryology lab immediately for evaluation under a microscope.⁴

If the first aspiration site does not yield adequate motile sperm, the needle can be redirected to other parts of the epididymis or the opposite side. The “percutaneous” part of the name simply means the needle goes through the skin without an open incision, which is what distinguishes PESA from its microsurgical cousin, MESA.

How Often It Works

Sperm retrieval success rates with PESA are generally high in men with confirmed obstructive azoospermia, though exact numbers vary depending on the study population and the cause of the blockage. In a study of 255 men, motile sperm were found in about 75% of cases, with an additional 9% yielding rare motile sperm and about 11% producing nonmotile sperm. Only around 5% of attempts found no sperm at all.⁵ Other series report even higher rates. In one study of 51 men, viable sperm were obtained from every single patient.⁶ A study focused specifically on men with CBAVD reported motile sperm in about 97% of attempts.⁷

The spread in these numbers reflects real differences in patient populations. The two factors that most consistently predict success are testicular volume and paternal age. Larger testes correlate with better motile sperm retrieval, while older age trends toward lower success.⁸ Another study of 89 men confirmed that viable sperm for use with in vitro fertilization was retrieved in virtually all cases, but the factors driving live birth rates down the line were the mother’s age and the number of fertilized eggs, not the retrieval method itself.⁹

PESA Compared to MESA and TESA

Three techniques dominate sperm retrieval for obstructive azoospermia: PESA, MESA (microsurgical epididymal sperm aspiration), and TESA (testicular sperm aspiration). Each has trade-offs, and fertility clinics sometimes have strong preferences based on their available expertise and equipment.

MESA involves an open incision into the scrotum, exposing the epididymis under an operating microscope. It typically yields larger quantities of higher-quality sperm, which is an advantage for cryopreservation. But it requires microsurgical skill, an operating room, and often general anesthesia, making it more invasive and expensive. PESA and MESA both retrieve epididymal sperm, and both are viable for IVF, with differences mainly in the equipment needed and sperm volume obtained.¹⁰ In at least one comparative study, PESA actually succeeded in some men where MESA did not: 15 of 20 men had successful PESA, and two of those had no success with MESA at all.¹¹

TESA takes a different approach entirely, aspirating sperm directly from the testicular tissue rather than the epididymis. It is often used as a backup when PESA fails. A meta-analysis comparing TESA and PESA found no significant difference in pregnancy or miscarriage rates, though TESA showed a modestly higher implantation rate.¹² On the other hand, a recent retrospective study found that PESA-derived sperm produced a higher proportion of good-quality embryos than TESA-derived sperm, while live birth rates between the two remained similar.¹³ Another study found that TESA sperm were associated with a lower fertilization rate and fewer usable embryos compared with PESA sperm after adjusting for other variables.¹⁴

The upshot is that when PESA works, the sperm it retrieves tend to be as good as or slightly better than testicular sperm for creating embryos. PESA is also faster and cheaper than MESA or TESA, since it can be done in a clinic under local anesthesia without microsurgical equipment.¹⁵ The main limitation is that it yields smaller volumes of sperm, which can be a problem if you want to freeze samples for future cycles.

Freezing Sperm Retrieved by PESA

One of the practical questions couples face is whether to use PESA sperm fresh on the same day as egg retrieval, or to freeze the sperm in advance. The good news is that frozen PESA sperm works. A study comparing fresh and cryopreserved epididymal sperm found no significant difference in fertilization, embryo cleavage, implantation, or pregnancy rates.¹⁶ Fresh epididymal sperm did show marginally higher fertilization rates in another analysis, but live birth rates were not significantly different between fresh and frozen groups.¹⁷

There is one nuance worth knowing about. A study looking at babies born from fresh versus frozen epididymal sperm found that singletons conceived with frozen sperm were, on average, about 90 grams lighter at birth after adjusting for confounders.¹⁸ That difference is small in absolute terms and may or may not be clinically meaningful, but it is one of the few measurable distinctions between using fresh and frozen PESA sperm. For most couples, the decision comes down to logistics: freezing in advance means the male partner’s retrieval and the female partner’s egg retrieval do not have to be perfectly synchronized on the same day.

Complications and What to Expect Afterward

PESA is one of the gentler procedures in the sperm retrieval toolbox. Minor pain and local swelling are common but typically resolve within a day or two. There have been no reports of percutaneous techniques causing complications severe enough to require hospital admission or significant medical treatment.¹⁹ The most frequently mentioned risks are small hematomas (bruises from the needle) and localized swelling. Percutaneous approaches carry a slightly higher risk of hematoma compared to open surgical techniques, simply because the needle enters without direct visual guidance.²⁰

One longer-term concern is fibrosis at the aspiration site. Repeated needle passes into the epididymis can cause scar tissue to form, which may make future aspirations harder.²¹ In the CBAVD series mentioned earlier, the complication rate was around 3%, all of which were minor.²²

What Pain Actually Feels Like During PESA

Fear of pain is a major concern for men facing this procedure, and the evidence is reassuring. In a study that tracked patient experience across 37 PESA procedures done under local anesthesia alone, the vast majority of men reported either no pain or only mild discomfort. About six experienced moderate but tolerable pain, and only two required supplemental sedation because the local anesthesia was incomplete. When asked afterward, most men said they would choose local anesthesia again if the procedure needed to be repeated.²³

Some clinics have begun offering needle-free jet injection devices for delivering the local anesthetic itself, which reduced both pain and discomfort scores compared to a standard needle in one trial. Interestingly, the jet device did not reduce anxiety scores, suggesting that the psychological component of the experience is somewhat independent of the physical pain.²⁴

When PESA Fails or Needs to Be Repeated

PESA does not always produce enough motile sperm on the first try, and some couples need multiple IVF cycles before achieving a pregnancy. The question then becomes whether you can go back to the epididymis again, or whether the scarring from prior attempts makes that impossible. The answer, reassuringly, is that repeat PESA is worth attempting. In one study, more than a third of repeat PESA procedures still yielded motile sperm, even after earlier aspirations had scarred the tissue.²⁵ That is lower than the first-attempt success rate, but still high enough that trying PESA again before escalating to TESA makes sense.

Many clinics use a “PESA with rescue TESA” protocol: they start with PESA, and if the aspirate does not contain adequate sperm, they switch to testicular aspiration in the same session. This combined approach means the female partner’s egg retrieval does not go to waste if PESA alone falls short.²⁶ In practice, the “try PESA first, escalate if needed” strategy gives you the benefits of the simpler procedure when it works without losing anything when it does not.

Pregnancy Rates and Baby Health

Retrieved sperm from PESA are used almost exclusively with ICSI, the technique where a single sperm is injected directly into an egg. The fertilization rates reported across studies range roughly from 55% to 78%, and live birth rates per cycle tend to land somewhere between 27% and 35% depending on the population studied.²⁷²⁸ When couples undergo multiple cycles, cumulative success improves substantially. One long-term study found that after five IVF cycles, the cumulative live birth rate reached 30% per transfer, while the cumulative delivery rate climbed to about 57%.²⁹

A reasonable concern for couples is whether babies conceived with surgically retrieved sperm face higher risks of birth defects. The data on this front is reassuring. A retrospective study found the rate of major birth defects in children born after PESA-ICSI was about 7%, with no significant difference compared to children born after testicular sperm extraction.³⁰ A national cohort study likewise found that total congenital malformation rates in children born from surgically retrieved sperm, at about 8%, were not significantly different from those born through standard IVF or ICSI with ejaculated sperm.³¹ These rates are broadly in line with what is seen across IVF populations generally, and no specific risk tied to the sperm source has been identified.

Cost and Practical Advantages

PESA’s biggest selling point beyond its clinical effectiveness is its simplicity. It does not require an operating room, general anesthesia, or a microsurgical setup. Compared to MESA and TESA, it is both faster and cheaper.³²³³ In resource-limited settings, the ability to do PESA in a clinic without specialized surgical equipment makes it especially appealing. It can be scheduled alongside the female partner’s egg retrieval or done in advance with cryopreservation, giving couples and clinics more scheduling flexibility.

The one area where PESA consistently falls short is sperm yield. Because the needle samples a tiny volume of epididymal fluid, the total number of sperm collected is usually smaller than what you would get with an open MESA. For a single fresh ICSI cycle, this is rarely a problem; you only need a few hundred motile sperm. But if you want to bank several frozen vials for future cycles, MESA’s larger yield becomes an advantage. Some clinics resolve this by doing PESA for the first cycle and recommending MESA if long-term cryopreservation is the priority.

When PESA Is Not the Right Choice

PESA only works when sperm are present in the epididymis, which means it is not appropriate for men with non-obstructive azoospermia, where the underlying problem is that the testes produce little or no sperm. In those cases, micro-TESE (an open surgery where the testes are examined under a microscope to find isolated pockets of sperm production) is the standard approach. If you have been diagnosed with azoospermia and your FSH levels are elevated or your testicular volume is notably small, those are clues that the issue may not be a simple blockage, and PESA would likely come up empty.

Men with a history of extensive epididymal surgery, severe prior infections, or epididymal cysts may also be poor candidates for PESA. The scarring in such cases can make it difficult to aspirate fluid, and a direct surgical approach may be preferred from the outset. Even in ideal candidates, the procedure is always paired with ICSI rather than conventional IVF, since the sperm numbers retrieved are too low for standard insemination of the egg.