6 Mayıs 2008 Salı

Infertility



Infertility is far more common than most people think. According to the American Society of Reproductive Medicine, approximately 6.1 million couples in the U.S.—about 10 percent of the reproductive-age population—experience fertility problems. For these couples, becoming pregnant is far from easy.
The truth is that hundreds of variables must coincide precisely for conception to occur and for a woman's body to successfully maintain a pregnancy for nine months. The average couple between ages 29 and 33 with no fertility problems has about a 20 to 25 percent chance of getting pregnant in any given month (or menstrual cycle).
There is no "typical" infertile patient. Ovulation and sperm deficiencies are the most common infertility problems, accounting for two-thirds of all cases.
Ovulation is a complicated communication process between the hormones in a woman's brain and the hormones in her ovaries. To understand ovulation problems related to infertility, you must first understand ovulation. As your menstrual cycle begins (day one of your period), your estrogen levels are low. Your hypothalamus (the area of your brain responsible for maintaining hormone levels) tells your pituitary gland to start producing a hormone called follicle stimulating hormone (FSH). The FSH triggers a few of your follicles to develop into mature eggs. One of these follicles produces the dominant mature egg and the others disintegrate.
Mature follicles produce estrogen, and estrogen tells your hypothalamus and pituitary gland that there is a mature egg ready to be released. The pituitary gland then produces a hormone called luteinizing hormone (LH) that causes the egg to burst through your ovary wall and begin its 24-36 hour journey through the fallopian tube to be fertilized.
Ovulation problems can occur due to a number of factors:
The ovaries may no longer contain fertilizable eggs,
Ovulation is disrupted because of a breakdown in the hormonal communication cycle
Scar tissue prevents ovulation from occurring (a rare occurrence)
Age is also a major factor in a woman's fertility. After age 35, a woman's fertility rapidly declines. By age 43, she has relatively little fertility left because her ovaries now produce fewer viable eggs.
The quality of a woman's eggs is critical to her chances of becoming pregnant. Egg quality is particularly important when a couple is considering in vitro fertilization or other assisted reproductive technology (ART) procedures. These procedures rely on the availability of multiple, high-quality eggs. Thus, in women older than 42, physicians may recommend using donor eggs.
While an older woman is more likely to have poor egg quality than a younger one, the condition can also affect younger women. In women age 35 who have been diagnosed as infertile, about 4.5 percent use donor eggs.
Less common identifiable fertility problems for women include structural problems or scarring of the fallopian tubes and/or uterus caused by pelvic inflammatory disease (PID) or endometriosis (a condition causing adhesions and cysts), uterine fibroids or, very rarely, birth defects.
Sperm deficiencies can include low sperm production (oligospermia) or lack of sperm (azoospermia). Sperm may also have poor motility—they don't move properly once inside the female reproductive tract to achieve fertilization. Additionally, sperm cells may be malformed or may die before they reach the egg.
About one-third of infertility cases are due to male factors and about one-third to factors that affect women. Roughly one-third of infertility is couple-related, with a combination of problems in both partners preventing conception.
An estimated 10-20 percent of infertility cases are unexplained; the source of the problem cannot be identified. However, with today's technology, diagnoses of unexplained infertility are declining.
Eighty-five to 90 percent of infertility cases are treated with medication or surgery. In vitro fertilization (IVF) and other types of assisted reproductive technologies (ART)—in which barriers to successful conception are overcome in the laboratory—account for only about five to 10 percent of infertility treatments.

Hiç yorum yok: