What is IUI (Intrauterine Insemination)?
IUI stands for Intrauterine Insemination, a fertility treatment where specially prepared (washed) sperm is placed directly into the uterus to increase the concentration of sperm at the site of fertilization, bypassing cervical barriers. 1
Definition and Mechanism
IUI is a simple, non-invasive assisted reproductive technique that deposits processed semen directly into the upper uterine cavity, overcoming natural barriers to sperm ascent in the female reproductive tract 2
The fundamental rationale is to increase gamete density at the fertilization site, even when sperm abnormalities or cervical mucus problems are present 1
The procedure uses refined sperm preparation techniques (originally developed for IVF) that isolate and select sperm with intact functional and genetic properties, including normal morphology, minimal DNA damage, and functional cell membranes 1
Clinical Context and Use
IUI is one of the most popular assisted reproduction methods worldwide, serving as a first-line treatment for many infertile couples 1
Primary Indications:
- Unexplained infertility (most common current use) 1
- Mild male factor infertility 1
- Cervical factor infertility 2
- Anovulation 2
- Individual women desiring pregnancy (using donor sperm) 1
Key Advantages:
- Simple and inexpensive compared to IVF, requiring minimal infrastructure 1
- Non-invasive with minimal risks when appropriately monitored 1
- High couple compliance compared to IVF programs 1
- Accessible in resource-poor settings where IVF is unavailable or unaffordable 1
Treatment Approach
IUI can be performed with or without ovarian stimulation (OS) 1:
- Natural cycle IUI: No hormonal stimulation
- Stimulated cycle IUI: Combined with medications (gonadotropins or clomiphene citrate) to develop multiple follicles 1
Stimulated IUI generally produces higher pregnancy rates (approximately 12% per cycle with FSH stimulation versus lower rates in natural cycles), though this comes with increased multiple pregnancy risks 3
Expected Outcomes
- Clinical pregnancy rates range from 10-20% per cycle depending on patient characteristics and protocol 2
- Success is highest in the first treatment cycle, with cumulative birth rates rising only slightly after the fourth cycle 4
- The procedure is most cost-effective for up to 3-4 treatment cycles before considering IVF 4