Intrauterine Insemination (IUI) is a common fertility treatment that works by placing sperm directly into a woman’s uterus. The primary goal of this procedure is to increase the concentration of healthy, motile sperm that reach the fallopian tubes, significantly reducing the distance the sperm must travel to meet the egg. This process is utilized for couples facing challenges like mild male factor infertility, unexplained infertility, or issues with cervical mucus. IUI is considered a less invasive and less expensive option compared to more complex assisted reproductive technologies like In Vitro Fertilization (IVF).
Initial Assessment and Ovarian Stimulation
The IUI journey begins with a thorough medical evaluation of both partners. This assessment ensures the procedure is appropriate and maximizes the chances of success. For the female partner, tests include blood work to check hormone levels, such as Anti-Müllerian Hormone (AMH) and Follicle-Stimulating Hormone (FSH), which indicate ovarian reserve. A key diagnostic step is confirming that at least one fallopian tube is open, often done through a hysterosalpingogram (X-ray procedure). The male partner undergoes a semen analysis to evaluate sperm count, motility, and morphology.
Depending on the assessment, the cycle is planned as either natural or medicated. In a medicated cycle, the woman takes ovulation induction medications to encourage the development of one or more eggs. Oral medications like clomiphene citrate (Clomid) or letrozole (Femara) are frequently prescribed early in the menstrual cycle. These drugs stimulate the pituitary gland to release more FSH, promoting follicle growth.
Injectable gonadotropins (containing FSH or FSH/LH) may be used if oral drugs are ineffective. This ovarian stimulation ensures ovulation occurs and potentially increases the number of eggs released, improving fertilization odds. However, using these medications increases the risk of a multiple pregnancy, requiring careful monitoring.
Tracking Follicle Development and Timing
Monitoring the growth of ovarian follicles determines the exact timing of insemination. This tracking involves regular transvaginal ultrasounds, often starting around cycle day nine or ten. The ultrasound measures the size of the dominant follicle and assesses the thickness of the uterine lining.
Blood work monitors hormone levels like estrogen and Luteinizing Hormone (LH). Estrogen levels rise as the follicle matures, and an LH surge indicates natural ovulation is imminent within 24 to 36 hours. In medicated cycles, timing is controlled using a human chorionic gonadotropin (hCG) injection, known as the “trigger shot.” This shot mimics the natural LH surge, prompting the final maturation and release of the egg.
The trigger shot is administered when the lead follicle reaches an optimal size (18 to 22 millimeters) and the uterine lining is sufficiently thick. Since ovulation is reliably induced 36 to 40 hours after the injection, the IUI procedure is scheduled precisely 24 to 36 hours after the shot. This strategic timing ensures the washed sperm are delivered to the uterus just before or as the egg is released.
Sperm Preparation and Insemination
On the day of the IUI, the male partner provides a semen sample, usually after a recommended period of sexual abstinence. Donor sperm is thawed if used. The raw semen sample cannot be inserted directly into the uterus because it contains substances that can cause severe uterine cramping.
The sample must undergo “sperm washing” or processing in the laboratory to isolate the healthiest sperm. This preparation removes seminal fluid, debris, non-motile sperm, and white blood cells. The goal is to create a highly concentrated population of the most motile sperm. The concentrated sperm is then re-suspended in a sterile culture medium, ready for insemination.
The IUI procedure is quick, typically lasting only a few minutes, and resembles a routine gynecological exam. The woman lies on an exam table while a speculum is inserted to visualize the cervix. A clinician gently threads a thin, flexible catheter containing the washed sperm through the cervix and into the uterus.
The concentrated sperm sample is slowly injected into the uterine cavity, bypassing the cervix entirely. Most women experience little to no pain, though mild cramping may occur as the catheter passes. After the injection, the catheter is removed.
The Two-Week Wait and Follow-Up
Following insemination, the patient enters the “two-week wait,” or luteal phase, before a pregnancy test can reliably detect the outcome. If fertilization occurs, the resulting embryo must implant in the uterine lining, which typically happens six to ten days after ovulation.
Patients are instructed to continue taking any prescribed medications, such as progesterone supplements, which support the uterine lining for potential implantation. They are also advised to maintain a healthy lifestyle, avoiding vigorous activity, smoking, and alcohol.
The pregnancy test is scheduled approximately 14 days after the IUI. This is performed using a beta hCG blood test, which is more sensitive than home urine tests. Testing too early can yield a false positive if the woman received an hCG trigger shot, as the hormone may still be detectable.
If the blood test is positive, the clinic confirms the pregnancy and provides instructions for continued monitoring. If the test is negative, the patient discontinues support medications, and the medical team discusses planning for the next treatment cycle.