What Is IUI and How Does It Differ from IVF
Intrauterine insemination (IUI) is a method in which specially processed and purified sperm from a husband or donor is inserted directly into a woman’s uterine cavity. The main goal of the procedure is to shorten the sperm’s journey to the egg and help them bypass the cervical barrier. The vagina has an acidic environment, and cervical mucus can be too thick or contain antibodies, which negatively affect the sperm.
In the laboratory, the semen is purified to remove seminal plasma, white blood cells, bacteria, and immotile cells. The result is a small volume of fluid with a high concentration of active and morphologically normal sperm.
The key difference between IUI and IVF lies in the method of conception. With IUI, conception occurs naturally inside the woman’s body (in the fallopian tube)—the doctor simply helps deliver the sperm. With IVF, fertilization occurs outside the body (in vitro): eggs are retrieved via puncture, fertilized in the laboratory, and then the embryo is transferred to the uterine cavity.
Thus, IUI is a less invasive procedure that does not require anesthesia or follicular puncture, and its cost is significantly lower.
Who is a candidate for intrauterine insemination
IUI is not a one-size-fits-all method, but it has proven effective for certain, primarily mild, forms of infertility.
Main indications:
- Female factor. Cervical factor infertility (cervical mucus prevents sperm from passing through). The method is also effective for vaginismus—a psychosomatic condition in which vaginal muscle spasms make sexual intercourse impossible. IUI is also used for mild ovulation disorders.
- Male factor. It is recommended in cases of moderately reduced semen analysis parameters (subfertile semen), the presence of antisperm antibodies, or ejaculatory disorders. Sperm preparation allows for the selection of the most viable sperm cells.
- Infertility of unknown cause. IUI is used as the first stage of treatment and is also the optimal option for single women or couples using donor sperm.
Preparation for the procedure: required tests for the couple
The success of IUI is impossible without thorough preparation. Both partners must undergo a comprehensive examination to rule out contraindications and assess the chances of success.
It is crucial for the woman to confirm the patency of her fallopian tubes, since fertilization occurs specifically within them. A patency test (using the HSG or EchoHSG method) is mandatory. The woman’s examination also includes an assessment of ovarian reserve, blood tests for hormones (FSH, LH, AMH, prolactin, thyroid hormones), and a pelvic ultrasound. Mandatory blood tests include screening for HIV, hepatitis B and C, and syphilis, as well as a vaginal swab for bacterial flora and a cytological examination (Pap test) to rule out inflammatory processes.
For men, the primary test is a semen analysis—spermogram. It allows for the assessment of sperm concentration, motility, and morphology. Additionally, a MAR test may be ordered to rule out an immunological factor contributing to infertility. Tests for infections are also mandatory.
How IUI Is Performed: Protocols and Cycle Day
The entire process, from preparation to the procedure itself, consists of several distinct stages. First, the semen must be collected and prepared. On the day of the procedure, the man provides a semen sample. In the laboratory, the semen is processed: it is purified, washed, and the most active sperm are concentrated in a small volume of culture medium.
The procedure can be performed according to two different protocols. The choice depends on the woman’s health: Determining the exact time of ovulation is critically important. Insemination is performed during the most fertile period—either on the day of ovulation or a few hours before it. This usually occurs on days 13–15 of the menstrual cycle.
- Natural cycle. The doctor monitors the maturation of the dominant follicle using ultrasound. Suitable for women with regular ovulation.
- Stimulated cycle. Mild hormone therapy is prescribed to increase the chances of conception. The goal is to ensure that no more than 1–2, or at most 3, follicles mature, in order to avoid the high risk of a multiple pregnancy.
The sperm injection procedure itself is very simple and painless; it is performed on an outpatient basis in a gynecological chair without anesthesia. The sensation is comparable to a routine gynecological exam. The doctor inserts a thin catheter through the cervix and gently releases the prepared sperm into the uterine cavity. After the procedure, the patient rests for 15–20 minutes and can then resume her normal daily activities.
IUI Effectiveness: Pros and Cons of the Method
Statistically, the probability of achieving pregnancy on a single attempt averages 10–15%. This rate may be higher (up to 20%) in young women with a cervical factor and decreases significantly with age.
The undoubted advantages of the method include its close resemblance to natural conception, minimal invasiveness, minimal medication use, and low cost.
Despite these advantages, IUI also has significant drawbacks. The main one is its relatively low effectiveness. The 10–15% success rate is significantly lower than that of IVF. Additionally, the method is completely ineffective in cases of blocked fallopian tubes, severe male factor infertility, or severe endometriosis.
Reproductive specialists recommend undergoing no more than 3–4 cycles of IUI. If pregnancy has not occurred by that time, the couple is advised to proceed with IVF. The outcome of the procedure can be determined through a blood test for hCG 14 days after the procedure.
