# Situation: A nurse at the infertility clinic of a tertiary hospital assesses couples who have been unable to conceive and teaches them about fertility tests. A 33-year-old husband submits a semen specimen after 3 days of abstinence. The results are: Volume: 2.8 mL Sperm concentration: 18 million/mL Total number of sperm: 50 million per ejaculate Progressive motility: 21% Normal forms (strict criteria): 5% Vitality (live sperm): 68% Based on the World Health Organization (WHO) 2021 lower reference limits, which result is below the reference limit?

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> subject: Nursing Practice II — Maternal and Child Health Nursing

## 문제

Situation: A nurse at the infertility clinic of a tertiary hospital assesses couples who have been unable to conceive and teaches them about fertility tests.

A 33-year-old husband submits a semen specimen after 3 days of abstinence. The results are:
Volume: 2.8 mL
Sperm concentration: 18 million/mL
Total number of sperm: 50 million per ejaculate
Progressive motility: 21%
Normal forms (strict criteria): 5%
Vitality (live sperm): 68%
Based on the World Health Organization (WHO) 2021 lower reference limits, which result is below the reference limit?

## 보기

1. Progressive motility **✔ 정답**
2. Sperm concentration
3. Normal forms
4. Total number of sperm

**정답: 1**

## 해설

The WHO 2021 lower reference limits are: volume 1.4 mL, concentration 16 million/mL, total sperm number 39 million, progressive motility 30%, normal forms 4%, and vitality 54%. Only progressive motility (21%) falls below its limit. A single abnormal result does not prove infertility, so the analysis is repeated and interpreted with the whole picture.

## 심화 해설

WHO 2021 Semen Analysis Reference Limits

The WHO 2021 manual provides lower reference limits derived from the 5th percentile of a fertile population. These are not “normal versus abnormal” cutoffs in a simple sense; they represent the value below which only 5% of men who achieved a pregnancy fall. A result below a limit means the parameter is in the lowest 5th percentile of fertile men, which raises concern but does not by itself diagnose infertility.

The husband’s values are compared with the WHO 2021 lower reference limits as follows:

| Parameter | WHO 2021 Lower Reference Limit | Husband’s Result | Interpretation |
| --- | --- | --- | --- |
| Volume | 1.4 mL | 2.8 mL | Above limit |
| Sperm concentration | 16 million/mL | 18 million/mL | Above limit |
| Total sperm number | 39 million per ejaculate | 50 million per ejaculate | Above limit |
| Progressive motility | 30% | 21% | Below limit |
| Normal forms (strict criteria) | 4% | 5% | Above limit |
| Vitality (live sperm) | 54% | 68% | Above limit |

Only progressive motility falls below the reference limit. The correct answer is therefore 1. Progressive motility.

Why Progressive Motility Matters

Progressive motility refers to sperm that move forward in a straight line or in large circles, as opposed to non-progressive motility (twitching or small circles in place) or immotility. Forward movement is essential for the sperm to travel through the cervical mucus, traverse the uterus, and reach the ampulla of the fallopian tube where fertilization occurs. A progressive motility below 30% suggests that fewer sperm are capable of making this journey, which can reduce the probability of natural conception.

It is important to separate motility from vitality. Vitality measures the proportion of sperm that are alive, regardless of whether they move. A man can have a normal vitality but low progressive motility, meaning the sperm are alive but not swimming effectively. In this case, vitality is 68%, well above the WHO limit of 54%, so the low motility is not simply due to a high proportion of dead sperm. The problem is functional movement, not viability.

Clinical Interpretation and the Role of Repeated Testing

A single semen analysis with one abnormal parameter does not establish male infertility. Semen parameters fluctuate significantly over time due to transient factors such as febrile illness, stress, recent ejaculation frequency, medications, and laboratory variation. When one parameter is below the reference limit, the WHO recommends repeating the semen analysis after an appropriate interval, typically 2 to 3 months, which reflects the duration of a full spermatogenic cycle.

The 2021 WHO manual and the supporting distribution data emphasize that reference limits are derived from fertile men, not from a clean separation between fertile and infertile populations. Watch out! A value above the lower reference limit does not guarantee fertility, and a value below it does not prove infertility. The limits are screening tools that guide further evaluation.

In this scenario, the husband’s specimen was collected after 3 days of abstinence. The WHO recommends 2 to 7 days of abstinence before collection. Shorter abstinence can lower semen volume and sperm concentration, while longer abstinence can reduce motility and increase the proportion of dead sperm. The 3-day abstinence falls within the recommended window, so the low progressive motility cannot be attributed to an inappropriate abstinence period. This strengthens the need to repeat the test and evaluate the couple comprehensively.

Nursing Considerations in the Infertility Clinic

When teaching a couple about semen analysis results, the nurse should explain that the report is interpreted as a whole, not parameter by parameter in isolation. The most clinically informative combination is total sperm number, progressive motility, and normal morphology, because these three parameters together reflect the sperm’s ability to reach and fertilize the oocyte. In this case, total sperm number and morphology are acceptable, but progressive motility is impaired, which may warrant referral for further andrological evaluation, including assessment for varicocele, hormonal status, or lifestyle factors such as smoking, alcohol, or occupational heat exposure.

The nurse should also provide clear instructions for repeat collection: maintain 2 to 7 days of abstinence, collect the entire ejaculate into a sterile container, deliver the specimen to the laboratory within 1 hour while keeping it at body temperature, and report any recent febrile illness or medication use. These measures reduce pre-analytical error and improve the reliability of the repeat analysis.

## 임상 시나리오

WHO 2021 Semen Analysis Reference LimitsInterpreting a single abnormal parameter
The WHO 2021 lower reference limits are the 5th percentile of a fertile population: volume 1.4 mL, concentration 16 million/mL, total sperm number 39 million, progressive motility 30%, normal forms 4%, and vitality 54%.

In this case, only progressive motility (21%) falls below the limit. All other parameters are above their respective thresholds.

CautionA single abnormal result does not diagnose infertility. Repeat the analysis and interpret it together with the female partner's evaluation and the full clinical picture.

## 핵심 개념

- **Progressive motility** — Sperm moving forward in a straight line or large circles, essential for reaching the fallopian tube
- **Lower reference limit** — 5th percentile value from a fertile population; below this only 5% of fertile men fall
- **Total sperm number** — Sperm concentration multiplied by semen volume, reported per ejaculate
- **Normal forms** — Percentage of sperm with normal morphology assessed by strict criteria
- **Vitality** — Percentage of live sperm, distinguishing immotile live sperm from dead sperm

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