There is no sperm at all

What is azoospermia?

The absence of sperm in the ejaculate after proper laboratory assessment. There are two broad mechanisms and they are not variants of the same problem.

Obstructive azoospermia

Sperm production is often essentially normal, but the sperm cannot get out. Causes include previous vasectomy, congenital absence of the vas deferens, previous infection or surgery, ejaculatory duct obstruction, and epididymal obstruction.

Non-obstructive azoospermia

Here the problem is production itself. It can be extremely low and patchy rather than uniformly absent — tiny islands of active production may persist even when nothing reaches the ejaculate.¹ That biological fact is what makes surgical retrieval possible at all, and it is also, as you will see, the reason a blind needle is a poor instrument for the job.²

Should the result be confirmed?

Yes. NICE recommends repeating semen analysis promptly when azoospermia or severe oligozoospermia is found, rather than waiting the usual three months.³ Laboratory technique matters, because rare sperm can be missed unless the sample is centrifuged and examined carefully.

A confirmed result should then trigger a proper male-factor evaluation rather than being treated as a single laboratory line.

What needs to be established before any operation

History, examination, hormones and genetics together tell you which mechanism you are dealing with. That means testicular size and consistency, whether the vas deferens is present, previous surgery, infection, undescended testes or chemotherapy, FSH, LH and a morning testosterone, and genetic testing.

Under NICE, men with idiopathic azoospermia should have Y-chromosome microdeletion testing and a karyotype; CFTR testing is recommended where obstruction or a vasal abnormality is suspected.⁴ There is also emerging evidence that point-of-care scrotal ultrasound in the clinic helps separate obstructive from non-obstructive disease before the retrieval method is chosen.⁵

None of this is academic. It determines both the chance of finding sperm and the counselling you should receive before anyone starts an IVF cycle around you.

The question nobody frames properly: which operation are you being offered?

This is the section I would most like men to read before they consent to anything.

Three operations get discussed, and they are not equivalent.

• TESA — testicular sperm aspiration. A needle through the skin into the testis, with suction. Quick, done under local anaesthetic, no incision.⁶⁷
• Conventional TESE — an open biopsy taking tissue from one or more sites.
• Micro-TESE — the testis is opened and searched under an operating microscope for the tubules most likely to contain sperm, with small targeted samples taken for immediate examination by an embryologist.

In obstructive azoospermia, where production is intact, the simplest option is usually enough. One series reported sperm retrieved in 82 out of 82 men — a 100% retrieval rate — using TESA for obstructive azoospermia,⁷ and a recent cohort found fertilisation, pregnancy and live-birth outcomes after ICSI comparable to other sperm sources once sperm had been obtained.⁸ If your problem is a blockage, a needle under local anaesthetic is a reasonable operation and I will not talk you into a bigger one.

In non-obstructive azoospermia the picture is completely different, and the evidence here is unusually good.

A randomised clinical trial of 100 men compared multiple needle-pass TESA against micro-TESE. Sperm were found in 22% after TESA and 43% after micro-TESE.² A systematic review and meta-analysis had already found conventional TESE about twice as likely as TESA to retrieve sperm, with micro-TESE outperforming conventional TESE in turn.⁹ Observational work agrees: a 320-man cohort found TESA positive in 22.2%,¹⁰ and an earlier prognostic series reported 30%.⁷

Compare that with micro-TESE across 4,895 men, where sperm were retrieved in about 46.6% overall and 46.8% at a first attempt — with wide variation between studies, from roughly 18% to 71%, because non-obstructive azoospermia is not one disease.¹

The reason is anatomical rather than technical. When production is focal, a blind needle samples wherever it happens to land.¹¹ A microscope looks for the right place.

Guidelines and reviews accordingly favour micro-TESE, or at least open TESE, for most men with non-obstructive azoospermia.¹²¹³

But is the simpler operation safer?

Somewhat, and this is the honest counterweight.

In one comparative study, complications occurred in 3% after TESA against 21% after micro-TESE, though the micro-TESE group was much smaller.⁷ In the randomised trial, no complications followed multiple needle-pass TESA, while 6% of men having micro-TESE needed a surgical intervention for a complication.²

So the trade is real. What it is not is a close call in non-obstructive azoospermia: a lower complication rate is poor compensation for halving your chance of finding sperm at all, particularly when a failed retrieval usually means a wasted egg-collection cycle for your partner and a second operation later.

Does a 47% retrieval rate mean a 47% chance of a baby?

No. This is the most important distinction in the whole subject.

Sperm retrieval is the first step, not the outcome. In the same large micro-TESE review, when retrieved sperm were used for ICSI, fertilisation was about 57%, clinical pregnancy occurred in about 39% of couples who reached embryo transfer, and live birth in about 24% of those couples.¹

Those are different denominators. Not every man has sperm retrieved. Not every retrieval coincides with eggs being available. Not every fertilised egg becomes a transferable embryo, and not every transfer produces a live birth. Multiply the pathway through and roughly one man in seven who starts down this road with non-obstructive azoospermia eventually fathers his own biological child.

You should hear that number from me rather than find it later.

What the ICSI figures do and do not show

Recent series look encouraging and need reading carefully.

A large retrospective cohort that controlled for female factors by using donor oocytes reported, after TESA-ICSI for azoospermia, a 76.5% blastocyst formation rate, 74.8% clinical pregnancy and 63.5% live birth.¹⁴ Another found cumulative live birth of 49.8% per initiated cycle where TESA was performed for azoospermia.¹⁵

Both are genuinely good numbers, and both describe men in whom sperm had already been found. Donor oocytes also remove the single largest variable in the arithmetic, which is your partner's age. Most reproductive-outcome studies in this field are retrospective, single-centre, and include only successful retrievals — which makes the journey look smoother than it is.¹⁵¹⁶

For non-obstructive azoospermia, the hurdle is still finding sperm in the first place.

Can anyone predict who will have sperm found?

Only imperfectly, and that remains the hardest part of the consultation.¹⁷¹⁸

Some things shift the odds. Cause matters: micro-TESE series consistently show better retrieval in men with previous undescended testes or orchitis, and worse retrieval in idiopathic disease.¹⁹²⁰ Genetics matter more. Complete AZFa or AZFb deletions are effectively an absolute contraindication — retrieval is close to zero — whereas AZFc deletions still carry around a 40% chance in pooled analysis.²¹²² NICE specifically recommends not offering surgical sperm retrieval where AZFa or AZFb microdeletions are present.⁴

For needle aspiration specifically, lower FSH and higher inhibin B were associated with a positive result, while men with Y-chromosome microdeletions or Klinefelter syndrome had negative TESA results in that series.¹⁰ A meta-analysis in men with chromosomal abnormalities similarly found lower LH and FSH associated with positive retrieval.²²

Histology helps too — hypospermatogenesis is far more favourable than Sertoli-cell-only or maturation arrest — but histology often only becomes apparent through sampling, and because production is focal, an earlier biopsy can underestimate what exists elsewhere.

What are the risks?

In the large micro-TESE review, short-term complications ran at about 3%.¹ Pain, swelling, bruising or haematoma, infection, injury to testicular tissue and a temporary fall in testosterone are all possible; longer-term endocrine impairment or atrophy is rare.

Testosterone can drop transiently after any retrieval, and endocrine follow-up is reasonable — particularly in men with small testes, borderline testosterone, Klinefelter syndrome, previous cryptorchidism or adverse histology.¹¹²³

What if the first attempt fails?

A negative procedure does not always close the door, but the odds fall. Reviews of repeat micro-TESE after an initially negative operation report retrieval in roughly 10–21%, with some selected series higher.²⁴

The decision turns on the original operative findings, histology, genetics, hormones, time since surgery, your partner's situation, and whether another egg-collection cycle is planned. It should not be automatic in either direction.

How strong is the evidence?

Mixed, and worth separating.

Strong: the randomised comparison of needle aspiration against micro-TESE in non-obstructive azoospermia,² and the meta-analysis of retrieval techniques.⁹ Strong: the genetic contraindications, which are consistent across large multicentre work.²¹ Moderate: the pooled retrieval and ICSI figures, which come from a very large but observational literature rather than randomised trials.¹ Weak: prediction in the individual man, where no blood test yet performs well enough to rely on.¹⁷¹⁸

Bottom line

Azoospermia is a serious diagnosis, but "no sperm in the ejaculate" is not the same as "no possibility of biological fatherhood."

Confirm the result. Establish whether it is obstructive or non-obstructive, and complete the hormonal and genetic work-up before anyone operates. If it is obstructive, the simplest retrieval is usually the right one. If it is non-obstructive, the operation should be a micro-TESE, and a randomised trial is the reason I will say so firmly.

Then hold two numbers apart in your head: the chance of finding sperm, and the chance of a baby. Any clinic that quotes you only the first has told you the easier half.

No sperm in the ejaculate is not the same as no sperm being made. But I will give you the honest denominator, and if I think the operation you have been offered is the wrong one for your type of azoospermia, I will tell you that too — before your partner starts a cycle rather than after.

Worth reading alongside: what a semen analysis can and cannot tell you, and the full appraisal of the evidence behind surgical sperm retrieval.