Sterility is defined as a biological inability to achieve a pregnancy after 12 months of regular (at least twice weekly) unprotected, not timed intercourse.
Why does this happen to me?
The monthly probability of conception of a normally fertile couple is 20-30%, increasing up to 81% after one year. In Spain, it is estimated that infertility affects about 700,000 couples, with a yearly incidence of new 44,000 cases. This tendency has been reported to increase with each passing year.
Sterility in a couple can be due to male factors (35%) or female factors (35%). Combined causes account for 20%, while 10% of sterility cases remain unexplained.
Sterility or infertility?
Although both terms are used interchangeably, sterility must be distinguished from infertility. Sterility indicates absolute inability to conceive, while infertility implies an apparent failure of a couple to produce a live child –as with recurrent miscarriages. Both conditions can be treated successfully with assisted reproductive procedures.
Why is sterility an increasing problem today?
Sterility is a problem which is becoming more and more common today. There are two primary reasons for the increasing incidence of sterility:
- The current trend to conceive at an older age causes a decrease in natural fertility rates. Today, due to financial and professional reasons, couples delay childbearing until later in life. Even though the ideal childbearing age is between 20 and 30, most couples choose to have their first child between the age of 30 and 40, or even later. And this happens in spite of the fact that age is known to be the most significant factor in achieving pregnancy.
- A decline in male fertility. Over the last few decades a marked decline in the quantity and quality of sperm production has been observed. Environmental factors, including diet and lifestyle, are believed to be responsible for this decline.
What is the origin of sterility?
Among the causes of infertility in women they are:
- Tubal disorders (40%) are anatomic defects which impair tubal normal function. Sequels of infectious or inflammatory processes like pelvic inflammatory disease, post-miscarriage infections, puerperal infections, endometriosis, hydrosalpynx, etc. are often causes of tubal disorders. They can be diagnosed with supplementary techniques such as X-rays, ultrasound or endoscopy.
- Ovarian disorders (40%) include ovarian failure, ovarian disfunction, luteal phase disorders, endometriosis, etc.
- Anatomic disorders (10%), such as uterine adhesions, endometrial polyps, fibroids, etc. are often associated to miscarriages.
- Impaired sperm migration. Sperm migration can be impaired by vaginal infections, septum, cervical infections, etc.
Female sterility is also caused by thyroid disorders, serious systemic diseases, obesity, drastic weight loss, and drug and toxic substance abuse, including tobacco and alcohol.
Male sterility cases are generally related to bad sperm quality. Male factors include a range of disorders affecting sperm count, motility and morphology. It must also be said that a normal sperm analysis does not necessarily mean that sperm is fertile. There are numerous possible disorders which determine the capacity of sperm to create a viable embryo.
Normal values for interpretation of a sperm analysis
A sperm analysis allows for study of sperm count, motility and morphology. Normal count is considered to be above 20 million/ml. If the sperm count is below this value the condition is defined as “oligozoospermia”.
Sperm motility is divided into four different grades according to motility scores:
- Type D or grade 0: Sperms are immotile and fail to move at all. They may be alive but not moving.
- Type C or grade +: Sperms move their tails but do not swim forward.
- Type B or grade ++: Sperms swim forward but either slowly, or in a curved motion.
- Type A or grade +++: Sperms swim fast in a straight line.
Sperm motility is considered to be normal when type A sperms are over 25%, or types A + B are over 50%. When these values are not reached, sperm condition is defined as “asthenozoospermia”.
There are several criteria to determine sperm morphology, among which Kruger Strict Criteria are the most commonly used. According to those criteria, a sperm cell is considered to be normal when no morphological abnormality is found under a microscope magnification of 1000x. Normal sperm value must be over 14%. When the percentage of normal sperms is lower, the condition is defined as “teratozoospermia”.
In some cases, both the man and the woman may be infertile so that the couple’s sterility arises from the combination of these conditions. This subfertility may decrease pregnancy chances to the extent that pregnancy cannot be achieved naturally.
What exactly is causing your problem?
In order to find out the reasons for delay in pregnancy, a so-called fertility study can be performed after a year of unsuccessful unprotected intercourse.
What chances of success do couples have at IMFER?
At IMFER the application of the highest quality standards together with the application of the most advanced knowledge in the field of human reproduction and the friendly way in which we treat our patients make the expectations for success be the highest. These factors together with a highly skilled, committed staff increase the chances for success up to the maximum. At IMFER we seek to solve each of your needs.