For a woman to become pregnant, a man’s sperm must ascend through the vagina through the cervix into the uterus (womb) and into one of the fallopian tubes. If the sperm reach the fallopian tubes as soon as the ovum is released from the ovary (ovulation), the sperm and the ovum may be found, most often, in the tube, on the side where the ovulation occurred, and thus may have place the fertilization.
Because the cervix (entrance to the womb) naturally limits the amount of sperm entering the uterus, only a few sperm reach the fallopian tubes. Intrauterine insemination (IUI) is a procedure in which sperm are placed inside a woman’s uterus near the time of ovulation. The placement of the sperm directly into the uterus shortens the trip to the fallopian tubes; therefore, there is a greater chance that more sperm will get closer to the egg. This procedure is carried out to improve the chances of a woman becoming pregnant.
When is the IUI useful?
There are many reasons why couples experience difficulties in having a child, and IUI can be useful for some of them.
Feminine infertility. Women who do not release an egg regularly (ovulation) can take medications to ovulate steadily. It is possible that these women must undergo an IUI so that the insemination occurs at the moment of ovulation. In addition, IUI is useful when a woman’s cervix prevents sperm from entering the uterus through the vagina due to scars from previous surgery. This can be seen in women who underwent surgery of the cervix (cryosurgery, cone biopsy, loop electrosurgical excision procedure [Loop Electrosurgical Excision Procedure, LEEP], etc.).
Infertile women sometimes take medications (orally or by injection) that cause the ovaries to produce several ovules at once. Apparently, these women are more likely to get pregnant if they also undergo an IUI.
Male infertility IUI is useful for infertile couples because the man has problems having an erection or ejaculating. For example, retrograde ejaculation takes place when sperm are redirected into the bladder instead of through the penis at the time of male orgasm. Many diseases can cause retrograde ejaculation. The sperm can be recovered from the urine and used for an IUI.
It is possible that the IUI is useful if the man has an abnormal opening of the urethra (orifice of the penis). In addition, IUI is used when the sperm count is low or when sperm movement is not optimal.
Preservation of fertility. Men can collect and freeze (cryopreserve) their sperm for future use before having a vasectomy, testicular surgery, or radiation treatment or cancer chemotherapy. In this way, they can use the sperm later for an IUI.
Reproduction with donor An IUI is performed when couples use sperm from a man who is not the partner of the woman who will have the baby. This is called donor insemination (ID). ID is commonly performed when the quality of the male’s sperm is severely compromised and it is not advisable to use his sperm for conception, and in vitro fertilization is not an option. The ID can also be used when the man has certain diseases.