Infertility is defined as not being able to conceive a child after an extended period of trial. Internationally definitions of infertility differ regarding the duration of time a couple has to have tried to achieve pregnancy. The World Health Organization (WHO) has agreed on setting the time of trial to two years while we, in Sweden regard one year as sufficient to start investigating infertility.

We can help find the cause of your infertility with a fertility investigation.


How common is infertility in different age groups?

The word “infertility” has high emotional implications, especially for the young women and men affected by it. Infertility is however not as uncommon as most people may believe. In the Swedish general population about 15% of people don’t achieve pregnancy after one year of actively trying. A woman’s fertility is at its highest at around 20 years of age, thereafter it decreases progressively with time. The most important reason of this decrease is the loss of the oocyte (egg cell) reserve within the ovaries, along with a simultaneous decrease in egg cell quality. There are a multitude of European studies on the proportion of infertile couples in different age groups. The approximate results have been:

  • 20 y.o.a. 4% infertile
  • 25 y.o.a. 6% infertile
  • 30 y.o.a. 9% infertile
  • 35 y.o.a. 17% infertile
  • 40 y.o.a. 35% infertile


Infertility may be divided into primary and secondary infertility. Primary infertility refers to infertility of a couple or in a woman who have never before been pregnant. Secondary infertility includes women or couples who have previously achieved pregnancy or even conceived children but who no longer, after one year of trial, have been able to achieve pregnancy.


Reasons of infertility, main groups:

The cause of infertility in a heterosexual couple may be a condition in the female, male or in both partners. Typically the cause is found in the female in 1/3, in the male in 1/3, and in both in 1/3 of cases. Reasons of female infertility can largely be subdivided into hormonal disturbances, damage to the Fallopian tubes and anatomical variations in the internal genital organs.

If the underlying cause of infertility is found in the male partner this is usually seen by our lab analysts as an abnormality in the sperm test. The reason behind these abnormalities is often, just as in the female counterpart hormonal or anatomical in origin. In a large group of patient no specific reason of infertility can be explained, this is termed “unexplained infertility”. The treatment options we offer such as IVF and ICSI will also increase the chances of pregnancy for this group of patients.


Female infertility



A woman’s age is the most important factor when considering her chances of getting pregnant and giving birth to a healthy baby. At puberty the two ovaries (organs carrying human egg cells) contain about 400 000 oocytes (egg cells) which, at the time of adolescence are kept resting in the so-called “primordial follicles”. Throughout the rest of a woman’s fertile period, until she reaches menopause, the stores of oocytes are depleted, mainly by around 50 single egg cells dying by self-death or so-called “apoptosis” each day. The process of apoptosis increases in rate after the woman reaches about 35 years of age. There are large differences in the oocyte reserve between different women at the same age. Some women have completely depleted oocyte reserves even before the age of 35 while others may have quite significant stores left.




Hög (ca. 20 år)




Medelstor (ca. 30 år)



Låg (ca. 40 år)


Disorders of ovulation

Ovulation is the process of final egg cell maturation and release of the mature cell from the ovarian follicle. During early ovulation an oocyte matures within an enlarged ovarian follicle, and when the oocyte is fully matured the enlarged follicle will rupture releasing the egg cell. Later the oocyte is, quite literally caught by the Fallopian tube, where fertilization by a sperm cell occurs. Thereafter the newly formed embryo descends through the tube into the uterus. The process of ovulation is complex and very delicately controlled by an interplay between hormones of the the ovaries and especially two brain centres called the hypothalamus and pituitary gland. If there are any disturbances in either the brain centres, the ovaries or the communication between the two – ovulation will not occur.
Some of the more common reasons of disorders of ovulation include:

Malnutrition or too rapid weight loss
Excessively strenuous physical exercise
Psychological stress
Morbid obesity

Polycystic Ovarian Symptom (Stein-Leventhal syndrome)

PCOS is the most common female hormonal disorder affecting almost 10% of all women. The disease is named after the characteristic ultrasound appearance of the ovaries in the disease with a band of small follicles (cysts) on the surface of the ovaries. In women with PCOS the ovaries produce increased amounts of male sex hormones (androgens). This overproduction affects the ability of the ovaries to develop normal egg-cell containing follicles and the result is often follicles of a small size that can not release their egg cells .The increased levels of male sex hormone may also cause other symptoms such as increased hair growth (hirsutism), acne and oily skin. Fortunately infertility connected to PCOS can be treated with ovulation induction or IVF.


Fallopian tube obstruction (tubal factor infertility)

Normally the Fallopian tube transport the egg cells down from the ovaries towards the uterus and the sperms up into the middle part of the tubes, where fertilization of the egg cells normally occurs. A few days later the fertilized egg (embryo) is transported down through the oviduct, into the uterus, where it will implant and grow until term. In some patients the Fallopian tubes become obstructed after infections like chlamydia or other sexually transmitted infections. Other causes of tubal factor infertility include inflammation, for instance an appendicitis, or pelvic surgery. If the Fallopian tubes are obstructed the normal process of transport and fertilization cannot occur. Then we can bypass this obstruction by using IVF.


Uterine factor infertility

About 1% of women have some disability to the uterus, resulting in it being unable to carry a pregnancy. There are several reasons to why an embryo do not attach to the the inner lining of the uterus (endometrium) or is rejected and leading to a miscarriage. Yet another reason to this kind of infertility is adhesions within the uterine cavity, these may for instance be caused by surgical abortions or infections of the uterus. Uterus factor infertility has, until now been untreatable. Prof. Mats Brannstrom led the first successful uterus transplant which resulted in the birth of a healthy baby boy in early September 2014. We, at Stockholm IVF are in a unique position to offer consultations about the possibility of uterus transplantation.



Endometriosis is a complex and, to date not yet fully understood disease. Simplified, the disease is caused by the presence of uterine endometrium (inner cell layer) outside the uterus. The disease causes painful menstruations and abdominal pain from time to time. There are several reasons why endometriosis may cause infertility. Cysts of endometrium may for instance be present on the ovarian surface preventing normal ovulation. Endometrial cysts may also cause adhesions that will interfere with the function of the Fallopian tubes. Local biochemical and immunological mechanisms may cause difficulties in fertilization of the oocyte within the Fallopian tube.



Prolactin is one of the pituitary hormones and its most important function is to stimulate breast milk production from the mammary glands. Prolactin levels are normally low in women who are not pregnant or breastfeeding. Increased levels of the hormone may be caused by a small so-called microadenoma that secretes prolactin independently of the normal regulation. High levels of prolactin inhibit the function of the ovaries, impeding the development of follicles and ovulation.


Increased or decreased function of the thyroid gland

The thyroid gland is located in the frontal part of the neck. It releases thyroid hormones that regulate the body’s metabolism. In women with either decreased (hypothyroidism) or increased function (hyperthyroidism) of the gland negative effects may can be seen both on the ovaries and uterus, resulting in infertility.


Male infertility



Age has some impact on male fertility as both the quantity and quality of the sperm cells decrease with age. Although an age-dependant decrease of male fertility does exists, the process is less prominent than for females.


Reduced sperm quality

Most sperm samples that show anomalies usually have a decreased sperm count (low number of sperm cells) or decreased sperm motility (less movement). In most cases there is no apparent reason to why the sample is of low quality. In some cases high temperature is the cause, for instance due to very high temperature in the work environment. Other reasons to reduced sperm quality include is exposure to environmental toxins such as detergents or PCB.

Absence of sperm

In some very rare cases the sperm may be completely absent in the ejaculate sample (azoospermia). This may be caused hormone disturbances, genetic disorders or a complete blocked sperm duct, caused by for instance cystic fibrosis or previous testicular inflammation.


Last updated: 2016-02-15



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