Infertility
How do humans get pregnant?
Conception (or the event of falling pregnant) occurs when a sperm enters an egg (fertilisation) to form a potential baby. This enters the womb (uterine cavity) and takes hold (implantation).
Ovulation is the ripening and discharge of an egg from the ovary for possible fertilization. However, it is not necessary for intercourse to occur precisely at the moment of ovulation. Fortunately, there is actually about a 4 day window in which intercourse is most likely to result in pregnancy. In a typical 28 day menstrual cycle, Cycle Days 12-20 would be the most likely days for intercourse to result in pregnancy.
At this time, the woman's pituitary gland (a pea-sized gland located in the brain which controls other hormonal glands and organs such as the ovaries) dramatically increases production of luteinizing hormone (LH). This increase is known as the "LH surge". Within one and a half days of the LH surge, a follicle in the ovary ruptures and releases a mature egg (ovulation). The time around ovulation is the optimal time to have intercourse in order to enhance the chance for pregnancy. As soon as the LH surge is detected, intercourse should begin. Even though ovulation has yet to take place, sperm can live up to 72 hours within the female reproductive tract. Therefore, sperm should be present and ready for fertilization when the egg is released. Intercourse should again take place the day of ovulation and the following day to further optimize the chance for conception.
Assuming there are no fertility problems, it may still take several months to conceive. In fact a couple without fertility problems has only a 25% chance of making a baby each month. Therefore, timing intercourse may be very helpful to enhance the chance for pregnancy.
What is infertility?
Most couples assume that once they stop using birth control, pregnancy will happen immediately. Although this occurs without too much difficulty for the majority of couples, others may realise that conception may not be as easy as anticipated. Infertility is defined as the “inability of a couple to conceive after a year of unprotected intercourse”.
Many other factors must be present for fertilization to take place. The male must produce a sufficient number of normal, actively moving sperm in order to achieve conception. The female's reproductive tract must be able to receive sperm and allow them to migrate from the vagina, through the cervix and uterus, and into the fallopian tubes. The fallopian tubes must be healthy enough to perform their function of helping the sperm get to the egg, and then to protect and nourish the fertilized egg, and deliver it into the womb. Inside the womb, the endometrial lining must be able to allow implantation and nourishment to the embryo as it develops into a fetus. All of these factors must be present for a successful pregnancy.
How common is infertility?
Fifteen percent of all couples will experience some degree of difficulty conceiving over a period of one year. Of these, the majority will conceive in the following year. The chances of conception drop with the duration of infertility.
How is infertility diagnosed?
The diagnosis is usually made on the basis of:
- History
- Examination
- Blood tests
- Ultrasound scans
- Assessment of the uterus and tubes. this may involve a radiological procedure (hysterosalpingogram) or surgery (laparoscopy, hysteroscopy and dye studies).
What causes infertility?
Of all infertile couples, some abnormalities can be documented in about 90%. The other 10% have no identifiable cause.
In approximately half of all couples, there is some abnormality in the female partner and in 35% an abnormality in the male partner.
The main causes of infertility are:
- Problems with ovulation
- Problems with the tubes or the uterus
- Problems with the sperm
However, in a number of cases, no specific cause can be identified.
What are the treatment options?
There are a number of treatment options for infertility, depending on the symptoms and circumstance:
- Problems with ovulation
Ovulation problems may be corrected by medications to induce ovulation
- Problems with the tubes or uterus
These problems may be correctable through surgery, or may need to be bypassed through procedures such as intrauterine insemination or IVF
- Problems with sperm
Sperm problems may be corrected through intrauterine insemination or IVF
- Unknown problems
May unidentified problems can be corrected through IVF
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