What Are Sperm Morphology Defects? What Should Sperm Shape Be Like?

According to World Health Organization (WHO) definitions, the failure to achieve pregnancy despite regular unprotected intercourse for 1 year (12 consecutive ovulation periods) is defined as infertility. Infertile couples wishing to have children must be evaluated together by Andrology specialists and Obstetrics/Gynecology specialists.

Simultaneous control of couples who cannot have children naturally must be ensured. The first step in the evaluation of men is the application of the "spermiogram" test, also known as semen analysis. During the semen analysis performed in a hospital setting, information is obtained about sperm motility, pH value, count, and sperm shapes thanks to the Kruger test (strict criteria) included in the spermiogram.

Anomalies present in sperm morphology can lead to infertility problems as they may prevent sperm from penetrating the egg. Although it is not correct to generalize that men with sperm morphology defects (teratozoospermia) cannot have children, the fact that infertility can be encountered due to sperm morphology defects should not be ignored.

What is Sperm Morphology?

Sperm morphology, that is, the shape and structure of sperm; is an element that must be evaluated together with sperm count and motility. The distortion of the head, neck, and tail structure of sperm due to different reasons such as medical drugs used, exposure to chemicals, increased testicular temperature, alcohol consumption, smoking, genetic factors, and DNA anomalies is called sperm morphology defect.

In spermiogram results, information can be obtained about sperm count, motility, sperm volume, and sperm structure, in other words, the percentage rate of normal forms. Ideal values for sperm morphology, evaluated according to Kruger criteria within the scope of the spermiogram, have been determined by the World Health Organization.

What Should the Ideal Sperm Shape Be Like?

According to the World Health Organization, normal sperm have 3 basic parts: the head containing genetic material, the neck (midpiece) providing energy for sperm to move, and the tail creating sperm motility. The ideal characteristics of these parts can be listed as follows:

In an ideal sperm:

• There is an oval-shaped head 5-6 micrometers long and 2.5-3.5 micrometers wide (smaller than a needle point).

• There is a well-defined cap (acrosome) covering 40% to 70% of the sperm head.

• There is no visible anomaly in the neck, midpiece, or tail.

• Cytoplasmic droplets larger than half the size of the sperm head are not observed in the sperm head.

Within the scope of the spermiogram test, sperm morphology is defined by percentage values according to Kruger criteria. According to this evaluation:

• ≥ 15%: It can be understood that the sperm has ideal fertilizing characteristics.

• 5% - 14%: The probability of fertilization is low (sub-fertile).

• 0% - 4%: The probability of fertilization occurring naturally is very low.

Can Misshapen Sperm Fertilize an Egg?

Yes, they can. However, results of scientific studies have shown that male-factor infertility can occur depending on the increase in the number of misshapen sperm. Mostly, the presence of a high number of abnormally shaped sperm is associated with low sperm count and low motility. Nevertheless, spermiogram test results must be examined to reach a definite conclusion. In line with the results obtained, different steps can be taken to increase sperm quality and treat morphology defects.

Can Sperm Shape Defects Cause Miscarriage?

Although the relationship between recurrent miscarriage and sperm morphology defects is not known for certain, it can be stated that achieving pregnancy may become difficult due to sperm morphology defects. Men diagnosed with sperm morphology defects may be asked to make lifestyle changes in line with the causes impairing sperm quality. Additionally, in the case of recurrent miscarriages, not only the woman but also the man must undergo health checks.

What to Do for Immobile Sperm (Asthenozoospermia)?

Low sperm motility and sperm morphology defects are different factors affecting sperm quality. Sperm need to move in a forward direction (progressive motility) at a certain speed to fertilize the egg. When sperm motility is low, one must first be examined by urology and andrology specialists. The factor causing low sperm motility shapes the treatment methods.

Infertility Treatment Must Be Planned Delicately

Infertility can be female, male, or both female and male in origin. Treatment processes should be planned in line with the couples' age, general health status, and causes of infertility. Sperm quality treatment can be done in line with the factors lowering sperm quality. However, if couples do not have time to wait for treatment processes to have a baby, Assisted Reproductive Technologies (ART) such as IVF (In Vitro Fertilization) and vaccination (IUI - Intrauterine Insemination) can be resorted to. IVF treatment provides a high success rate when planned considering the special health conditions of the couples.