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Although infertility and sterility are often used interchangeably to refer to a couple’s inability to conceive and have children, these terms actually have distinct meanings. In this article, we will explore the differences between infertility and sterility, their diagnoses, and potential treatments.
Differences Between Infertility and Sterility
The primary difference between sterility and infertility lies in the specific stage at which the issue preventing pregnancy occurs:
- Sterility refers to the inability to achieve pregnancy because fertilization does not take place. A couple are considered sterile when they are unable to conceive after one year of regular, unprotected intercourse.
- Infertility refers to the inability to carry a pregnancy to term. In this case, fertilization occurs, but the embryo is unable to implant or develop to full term.
While both conditions result in the inability to have a child, infertility brings one closer to the possibility of conception. It is important to note that both terms refer to a period, generally one year, during which a couple or an individual has been unable to achieve pregnancy. For women over 35 years old, six months of unsuccessful attempts is sufficient to prompt an evaluation for underlying factors.
Causes of Sterility
Both infertility and sterility may arise from issues affecting either partner or a combination of both. Additionally, there are cases where the cause of sterility is unknown.
Female Sterility
Common causes of female sterility include:
- Endocrine factors: Hormonal issues impacting the menstrual cycle and ovulation, such as polycystic ovary syndrome (PCOS), anovulation (lack of ovulation), or premature ovarian insufficiency (early menopause), can prevent the egg from being released or available for fertilization.
- Tubal factors: The fallopian tubes are the site where the egg and sperm meet. Blockages or damage to the tubes, as seen in endometriosis or infections like salpingitis, can prevent this union. Even if fertilization occurs, transportation to the uterine cavity may be hindered.
- Uterine factors: Structural or shape-related issues with the uterus, such as congenital malformations, fibroids (benign tumors), or uterine adhesions, can prevent sperm from reaching the egg or hinder embryo implantation.
- Cervical factors: Abnormalities in the cervix, such as hostile cervical mucus or deformities, may impede sperm from entering the uterus, thus preventing fertilization.
Male Sterility
In men, the primary causes of sterility include:
- Pretesticular or endocrine factors: Hormonal imbalances affecting sperm production.
- Testicular factors: Conditions such as varicocele (enlarged veins in the scrotum), orchitis (testicular inflammation), cryptorchidism (undescended testicles), or trauma can impair sperm production and quality.
- Post-testicular factors: Although sperm are produced correctly, issues like obstructions in the vas deferens, retrograde ejaculation, erectile dysfunction, or seminal infections can prevent sperm from being properly ejaculated.
- Sperm factors: Poor sperm quality—such as issues with motility, morphology, or low sperm concentration in the ejaculate—can also hinder fertilization.
“Infertility occurs when fertilization takes place, but the pregnancy does not progress to term” A. Zavala
Causes of Infertility
Infertility occurs when fertilization takes place, but the pregnancy does not progress to term. While some causes overlap with those of sterility—such as endocrine issues, fallopian tube obstructions (e.g., from endometriosis), and uterine problems—infertility also includes factors related to the embryo’s ability to develop normally. These can include:
- Implantation failure: After fertilization, the embryo must implant in the uterine lining (endometrium) to continue developing. Issues such as insufficient uterine lining or malformations can prevent implantation.
- Miscarriage: In some cases, the embryo implants but development ceases, resulting in spontaneous pregnancy loss. This can stem from genetic, immunological, infectious, or embryonic quality issues, though the cause is sometimes unknown. Often, a miscarriage can be followed by a completely healthy subsequent pregnancy.
When implantation failures or miscarriages occur repeatedly (more than twice), the condition is termed recurrent implantation failure or recurrent pregnancy loss.
In general, infertility and sterility are attributed equally to female factors, male factors, and a combination of both.
“In general, infertility and sterility are attributed equally to female factors, male factors, and a combination of both” A. Zavala
Diagnoses and Treatments for Sterility and Infertility
Given the multitude of potential causes, it is crucial to visit a specialized reproductive centre if pregnancy has not been achieved after one year of regular, unprotected intercourse, or if pregnancy has occurred but recurrent losses have followed.
At Tambre, we conduct comprehensive, multidisciplinary evaluations to determine why fertilization or implantation is not occurring or why pregnancies end prematurely.
Treatments for Sterility
Depending on the diagnosis, we offer personalized solutions utilizing advanced technology. Common treatments for sterility include:
- Controlled ovarian stimulation: Hormonal medications are used to stimulate egg production in women with ovulation problems, increasing the chances of fertilization.
- Artificial insemination (AI): Processed semen is introduced directly into the uterus, facilitating sperm’s journey to the egg.
- In vitro fertilization (IVF): After ovarian stimulation, eggs are retrieved and fertilized with sperm in the laboratory. The resulting embryo is then transferred to the uterus.
- ZyMot-ICSI (formerly Fertile Chip): At Tambre, we use sperm DNA fragmentation testing to select the best-quality sperm before performing IVF with ICSI.
- Surgery: In cases of fallopian tube obstruction or uterine abnormalities, surgical correction may be necessary.
Treatments for Infertility
For recurrent infertility, where fertilization occurs but implantation or pregnancy progression fails, Tambre offers a range of solutions:
- Preimplantation genetic testing (PGT): Conducted during IVF, this testing identifies embryos free of chromosomal or genetic abnormalities, improving implantation success.
- Endometrial preparation: We employ protocols to optimize the endometrium’s condition and identify the ideal “implantation window” through personalized analysis and endometrial biopsy.
- Deferred blastocyst transfer: Embryos are cultured to the blastocyst stage (day 5-6 post-fertilization) for selection of those with the highest implantation potential. Embryos may also be frozen for later transfer, allowing for optimal endometrial preparation.
- Hormonal treatments: Medications support implantation and early pregnancy development.
- Immunological compatibility study: A simple blood test can reveal potential immunological incompatibilities between the embryo and the endometrium.
Comprehensive evaluation during your first visit at Tambre
If you suspect infertility or sterility, Tambre offers an in-depth initial consultation to provide a diagnosis and personalized treatment plan.
During this consultation, we can conduct a complete gynecological examination, ultrasound to assess the uterus, fallopian tubes, and ovaries, and a blood test to evaluate anti-Müllerian hormone (AMH) levels for ovarian reserve assessment.
For male partners, we offer semen analysis and sperm morphology studies to detect any abnormalities.
With this information, we can provide a tailored diagnosis and the most appropriate treatment for your case.
Additionally, a Personal Advisor will be assigned to guide and support you throughout the process, addressing any questions or concerns.
Contact Tambre now to schedule your first appointment at +44 (0) 20 38 688 650. We will diagnose your infertility or sterility issue and begin your personalized treatment immediately.
