Intrauterine Insemination (IUI) is an office-based fertility procedure designed to deliver a concentrated sample of highly motile sperm directly into the uterus. By bypassing cervical mucus and placing sperm closer to the fallopian tubes, IUI significantly improves the chances that sperm will meet the egg. At Marin Fertility Center, our fertility doctor oversees comprehensive fertility testing and a baseline ultrasound for IUI to confirm optimal timing and uterine readiness.
Intrauterine Insemination (IUI): Procedure, Comparison & Preparation
How IUI Delivers Sperm Effectively
Although an average ejaculate contains over 250 million sperm, most are lost within the female reproductive tract. When sperm finally reach the fallopian tube, only a few hundred may remain. Intrauterine Insemination (IUI) enhances this process by concentrating and placing the healthiest sperm directly into the uterus at the ideal moment—verified by a baseline ultrasound for IUI. This targeted approach ensures that more sperm are available in close proximity to the egg, making pregnancy more likely.
Who Should Consider IUI: Key Indications
IUI is recommended in several scenarios:
- Mild to moderate male-factor infertility: When semen analysis shows suboptimal sperm count or motility, IUI heightens pregnancy chances by delivering the best sperm closer to the egg.
- Donor sperm usage: For couples where partner sperm quality is extremely poor or for single women and same-sex female couples, donor sperm can be used following fertility testing.
- Ovulatory disorders: Women undergoing mild ovarian stimulation (monitored via fertility testing and ultrasound) who produce one or two mature follicles may benefit from IUI.
- Unexplained infertility: If basic fertility testing (hormonal profile, tubal patency, and baseline ultrasound for IUI) shows no apparent cause, IUI is often the first-line treatment.
Cost and invasiveness comparison (IUI vs IVF): Couples preferring a less invasive, lower-cost alternative to IVF often start with IUI before moving to IVF if necessary.
Your fertility doctor will evaluate your individual fertility testing results to determine if IUI is the appropriate next step.
Detailed IUI Cycle Steps with Baseline Ultrasound
Visit 1 — Baseline Ultrasound for IUI (Cycle Day 2–4)
This visit occurs on cycle day 1–4, marked by the first day of full-flow menstruation. Around cycle day 2–4, schedule your “baseline” ultrasound for IUI. The purpose of this baseline ultrasound is to verify that your ovaries are not “active” (no new cysts or large follicles) while you are menstruating. Completing fertility testing—such as hormonal labs and semen analysis—at this stage ensures a clear picture of your reproductive status. After the baseline ultrasound for IUI, our team will instruct you on when to schedule your first monitoring appointment.
Visit 2 — Monitoring Ultrasound Appointment for Follicle Development
A monitoring appointment confirms follicular development and assesses your response to any ovarian stimulation medication (if used). This ultrasound typically falls around cycle day 10. During this scan, your fertility doctor measures any growing follicles. In a natural cycle, one follicle typically matures; in a medicated cycle, the goal is often 2–3 follicles measuring 14–20 mm in diameter. Once follicles are mature, you will administer a “trigger shot”—an injectable medication that signals the eggs to release. The insemination procedure (IUI) is then scheduled 24–36 hours later.
Visit 3 — IUI Procedure: Sperm Preparation & Insemination
Sperm Preparation and Washing
On the day of your insemination, partner sperm or frozen partner sperm (after thawing) is collected. Partners should abstain from 2–4 days before collection to optimize sperm count. In our lab, we use advanced fertility testing techniques—such as the Zymot device—to wash and concentrate the sperm into a pellet. It takes approximately 90 minutes to process the semen. If you are using frozen donor sperm, the specimen arrives thawed from the sperm bank of your choice.
Insemination Procedure Under Ultrasound Guidance
IUI is a simple, comfortable office procedure requiring no anesthesia. Much like a routine Pap smear, the cervix is visualized, and a soft, thin catheter specially designed for comfort introduces the sperm into the upper uterus. After a brief five-minute waiting period, you can resume your normal day without restrictions unless otherwise instructed by your physician.
Post-IUI Care and Luteal Phase Support
After ovulation, the released egg’s follicle becomes the corpus luteum, which produces progesterone to support potential pregnancy. We commonly recommend vaginal progesterone supplementation after IUI to support implantation. Progesterone is administered as a capsule or ovule. The first pregnancy test is scheduled 14 days post-insemination, at which point you would be considered 4 weeks and 0 days pregnant. If positive, serial ultrasounds begin the following week (week 5 of pregnancy) to confirm proper implantation and monitor developmental milestones every 1–2 weeks thereafter.
IUI Cycle Preparation: Vitamins, Screening & Labs
Start a Prenatal Vitamin
If you haven’t already, start a daily prenatal vitamin as you prepare for IUI. Folic acid and essential micronutrients support early embryonic development and uterine lining health.
Update Preventative Screening Tests
Before attempting pregnancy, ensure the following are up to date:
- Pap smear
- Mammogram
Complete Expanded Carrier Screening (ECS)
Expanded Carrier Screening (ECS) is a genetic test identifying silent gene mutations associated with certain inheritable diseases. ECS detects autosomal recessive mutations, meaning offspring have a 25% chance of inheriting a condition if both parents are carriers. Without ECS, many carriers wouldn’t know their status until after the birth of an affected child.
Preconception and Infectious Disease Screening Labs
To proceed with IUI, these labs must be completed within the past 12 months:
- For the female patient: Blood type and Rh status, Rubella titer, Varicella titer, TSH and CBC.
- For both partners: RPR, HIV I&II, HBV Ag, HCV Ab, Gonorrhea and Chlamydia.
- For women using donor sperm: CMV IgG/IgM is also required.
Additional Diagnostic Tests (if needed)
Discuss with your provider whether you need:
- Saline sonogram
- Hysterosalpingogram
IUI Success Rates by Age & Diagnosis
- Peak Fertility (young fertile couple without difficulties): 20–25% pregnancy rate per cycle
- Male Factor Infertility: 15% pregnancy rate per cycle
- Frozen Donor Sperm: 15% pregnancy rate per cycle
Couples can compare IUI vs IVF success rates—while IVF may offer higher per-cycle pregnancy rates, IUI is less invasive, requires less intensive fertility testing and medication, and costs significantly less.
Schedule an IUI Consultation with Our Fertility Doctor
Ready to explore Intrauterine Insemination (IUI)? Schedule an appointment with our fertility doctor at Marin Fertility Center. We will review your fertility testing results, perform a baseline ultrasound for IUI, and develop a personalized IUI protocol.