What Causes infertility
Since the birth of Louise Brown in 1978 with the help of in vitro fertilization, the outlook for infertile couples has drastically changed. The advanced IVF techniques, Intra cytoplasmic sperm injection (ICSI), potent pro fertility medicines, high resolution ultrasound, safe and effective key hole surgery (laparoscopy and hysteroscopy) have helped millions of couples worldwide to conceive even in the presence of seemingly impossible situations. Acceptance of procreation with the help of donor sperms, eggs and uterus by the infertile couples, the society and the law of the country have widened the treatment options for even those couples in whom damage is beyond repair. Today, an infertile couple can look towards an 80-90% chance of conception. While the developments in the field are very exciting there are many pertinent questions which have arisen: Why is the incidence of infertility increasing? Is it real or apparent? What are the common reasons for infertility? How can we diagnose and prevent infertility? We shall try to answer some of these questions here.
Before we go in to the causes of infertility, we have to understand the normal process of conception. We can take the simple analogy of the development of a plant. The uterus is like the mother earth. The hormones which support and nourish the pregnancy are like water and fertilizers. The seeds i.e. sperm and ova (eggs) come from father and mother respectively. The two seeds combine to form an embryo or the sapling. Pituitary gland situated in the brain acts like the farmer – guiding, regulating and helping the whole process. Fecundity rate per month for any individual couple is only about 15-20 percent. Infertility is defined only if a conception fails to occur despite unprotected intercourse for more than 12 months. Conception may occur even in the presence of apparent milder problems. Therefore, investigations and treatment before one year are generally counter-productive. At the same time, the duration of infertility of more than three years has a negative impact. In older couples, investigations and treatment should be started early.
Infertility occurs commonly due to the present day life style factors, many of which are not conducive to pregnancy. The incidence of infertility is rising due to the causes that include delayed childbearing, obesity per se and the related disorders, increased sexual promiscuity and sexually transmitted diseases. In the males, there is a trend towards decreasing sperm counts. Obesity, sedentary life style, smoking, mental stress, air and chemical pollutants and use of electronic devices (etc.) have been also implicated. Of all of these issues, obesity is one factor which has a serious and direct bearing on fertility. In addition to infertility, obesity is an important contributory cause of poor success of treatment, abortions, malformations in baby and adverse pregnancy outcome. Many of these problems can be reversed by losing weight.
Ovarian problems: All females are endowed with a fixed quota of eggs by birth. There are roughly 300 thousand eggs at birth, of which only 300 finally mature and are released for fertilization during the whole menstrual life span of a woman (age 12 – 50). The rest of the eggs die a pre-programmed death at the rate of 3000-5000 per month. Contrary to common misconception, the fertile life span of women (age 18 – 40) is much shorter than the menstrual life span. Even in these age groups, the rate of fertility declines to less than 50% of the younger age. Decreased ovarian reserve due to delayed child bearing has become the single most common or contributory reason for infertility and reason for poor outcome in urban societies. No matter how healthy a woman remains, one cannot stop the aging process of the ovaries. The ovaries may be absent by birth, removed or destroyed by surgery, disease or toxic treatment related to life threatening diseases like cancers.
Polycystic ovarian disease or PCOD is a type of dysfunction of ovaries. Almost 20 – 30 % of women with infertility have this problem. This is related to genetic factors and obesity. Any gain in weight in a genetically predisposed individual can lead to abnormal hormonal function, menstrual anomalies and abnormal ovulation. A life style which is conducive to an optimal weight is the only available treatment which is likely to restore normal menstruation and ovulation. However, pregnancy can be achieved with the help of fertility hormones.
Pituitary or hypothalamic problems: Presence of tumour like conditions in the master gland – the pituitary, or in other areas of brain; tension, mental stress, anxiety all interfere with the hormonal control and menstrual cycle and may affect the normal ovulation process. Most of these problems except age can be treated with fertility medicines. However, 30% of these cases will also require in vitro fertilization procedures.
Fallopian tubes: Fallopian tubes are the connecting passages which pick up eggs from the ovaries with active suction, support them until they are fertilized with sperms, nurture the very early embryo and even move it to the uterus for implantation by wave like movements. Any blockage in the tubes is an absolute barrier to fertilization. Even with open tubes, the functions of egg pick-up, nutritional support of early embryo and embryo transport to uterus may be compromised due to infections like tuberculosis, post-abortal or post-partum infections and sexually transmitted diseases. The incidence of tuberculosis is increasing worldwide including that of genital tuberculosis. Genital tuberculosis is generally silent and asymptomatic. Even if healing occurs, either with the help of the body’s own defences or with medicine, there is a significant impact on the tubes because of scarring which is left behind. In severe cases even the ovaries or the uterus may get involved. Treatment is successful in reversing infertility only in very early cases. IVF is the only successful treatment for all cases of tubal block or dysfunction.
Uterus and endometrium: The uterus is a muscular organ which increases in size from the non-pregnant state (approximately equal to a lemon) to a one and half foot long structure during pregnancy. In addition to protection it also supplies the baby with nutrients through maternal blood for the nine months of pregnancy. Finally, the uterus helps to deliver the baby at term. All these functions can be impaired in various disease conditions e.g. moderate to big size fibroids or infections like tuberculosis. Abnormal shape of uterus by birth, operations or abortions, may also interfere with the process of implantation, growth of the baby or full enlargement of the uterus and may lead to abortions or pre term births
Endometriosis, responsible for almost 10% of infertility is a tumour like condition which occurs due to implantation of the lining of uterus in abnormal positions. The most common sites are ovaries and the lining of the female pelvic organs. These result in abnormal chemical composition of the peritoneal fluid, severe adhesions of pelvic organs, destruction of ovarian tissue and abnormal function of both ovaries and tubes. This is a progressive disorder leading to adverse consequences on wellbeing and fertility. The women may have progressive pain during menses or throughout the menstrual cycle. She may have bleeding problems. Infertility in them is difficult to treat. Most of these women require IVF for treatment which should be done early.
Problems in male partner: Male factor infertility is single most common cause of infertility. Male partner alone may be responsible for nearly one third of all infertility cases and contributory in another third. Total absence of sperms may occur due to the failure of testes to produce sperms or blockage in the passages. Sperms may also not be available because of sexual or ejaculatory dysfunction. Much more common is the lower sperm counts with abnormal shapes and poor fertilizing power. Unfortunately there is no potent pro fertility drug for males. However, the technique of ICSI or use of donor sperms can help most couples. Sperms can even be retrieved from the testes and injected inside the eggs with ICSI with fairly good results.
Unexplained infertility: There is a large subset of nearly 20% of infertile couples where no cause can be detected in both partners despite extensive workup. Here, the defect lies at the functional or biochemical level which is neither possible to diagnose with current workup techniques nor required. The treatment remains IVF in the most of these couples. Unexplained infertility in young couples is as bad as infertility due to any other cause. If pregnancy is not occurring at the best of age, the chances decreases with the growing years. IVF is indicated after 3-5 years of unexplained infertility in young couples also.
In conclusion, the first step to treat infertility is the elucidation of all the contributory causes in both the partners. It takes two to make one baby. There may be one or multiple causes in one partner or both the partners. Treatment has to be tailored according to the age, cause and duration of infertility. Too much, too little, too early and too late are all counter-productive in management of infertility. If a treatment modality fails for 3-4 treatment cycles – the same is unlikely to succeed. Spontaneous pregnancies are still possible. Unnecessary and futile treatment especially surgical intervention is more harmful than no treatment. It is better to opt for IVF or adoption in such cases.