IUI vs. IVF - Which Fertility Treatment is Right For You?

Fertility challenges affect many couples and individuals trying to conceive. Intrauterine Insemination (IUI) and In Vitro Fertilization (IVF) are two common fertility treatments used to increase pregnancy chances. Understanding their key differences, success rates, and suitability can help determine the best option for your fertility journey.

IUI vs IVF: Understanding the Key Differences

IUI involves placing sperm directly into the uterus using a thin catheter during ovulation, reducing the distance sperm must travel to fertilize an egg. It is less invasive, more affordable, and often the first-line treatment for mild male factor infertility or unexplained infertility.

IVF is an advanced fertility treatment where eggs are fertilized outside the body. It includes ovarian stimulation, egg retrieval, fertilization in a lab, and embryo transfer. IVF offers higher success rates and allows for genetic testing, making it suitable for blocked fallopian tubes, severe male factor infertility, or repeated unsuccessful IUI cycles.

The choice between IUI and IVF depends on the cause of infertility, medical history, and treatment goals.

IUI: A Less Invasive Fertility Treatment

IUI increases the chance of pregnancy by placing sperm directly into the uterus. It can be done in a natural cycle or with ovarian stimulation (OS) to increase the number of eggs available for fertilization.

Step 1: Ovulation Tracking

Ovulation monitoring ensures IUI occurs at the optimal time:

Ultrasound scans to track follicle development.
Blood tests for LH and estradiol levels.
Ovulation predictor kits (OPKs) for at-home tracking.

In a natural cycle, IUI is timed with spontaneous ovulation. In stimulated cycles, fertility drugs (Clomiphene, Letrozole, or gonadotropins) stimulate egg production while minimizing the risk of twins or multiples.

Step 2: Ovarian Stimulation (If Needed)

Oral medications (Clomiphene, Letrozole) for 5 days.
Injectable gonadotropins (FSH, hMG) for stronger stimulation.
If >3 mature follicles develop, the cycle may be canceled or converted to IVF.

Step 3: Sperm Collection & Preparation

The sperm sample (partner/donor) is washed and prepared to remove dead sperm and improve quality.
A minimum of 5-10 million motile sperm is recommended for success.

Step 4: Insemination Procedure

A thin catheter inserts sperm directly into the uterus.
The procedure is quick (5–10 minutes), painless, and requires no anesthesia.
Patients can resume normal activities immediately.

Step 5: Luteal Phase & Pregnancy Test

Progesterone supplements may be prescribed to support implantation.
Pregnancy test after 14 days.
If unsuccessful, 3-6 IUI cycles are attempted before considering IVF.

Who is IUI Suitable For?

IUI is recommended for:

Unexplained infertility (after 1 year of trying).
Mild male factor infertility (low sperm count or motility but treatable).
Cervical factor infertility (hostile cervical mucus blocking sperm movement).
Same-sex couples or single individuals using donor sperm.
Fertility preservation patients (e.g., cancer patients freezing sperm).

IUI is not recommended for severe male factor infertility or blocked fallopian tubes.

IVF: A Comprehensive Fertility Treatment

In Vitro Fertilization (IVF) is an advanced fertility treatment where eggs are fertilized outside the body before being inserted into the uterus. Below is a step-by-step breakdown.

Step 1: Menstrual Cycle Start (Day 1)

GnRH agonists (e.g., Lupron) may be used beforehand to prevent early ovulation.
Ovarian stimulation begins on Day 2 or 3 in a natural start cycle.

Step 2: Ovarian Stimulation

Hormonal injections (FSH, LH) for 8–14 days to increase the number of eggs.
Regular ultrasounds & blood tests track response and adjust medications.
Trigger shot (hCG injection) when follicles reach 18–22mm.

Step 3: Egg Retrieval

Minor surgical procedure under sedation or anesthesia.
Ultrasound-guided needle aspirates mature eggs.
Takes 20–30 minutes; most patients go home the same day.
Typically, 8–15 eggs are retrieved, depending on age and ovarian reserve.

Step 4: Sperm Collection & Preparation

Fresh, frozen, or donor sperm is washed and prepared.
ICSI (Intracytoplasmic Sperm Injection) may be used for low sperm count/motility.

Step 5: Fertilization

Standard IVF: Sperm and eggs are placed together in a dish for natural fertilization.
ICSI: A single sperm is injected into each egg (for male infertility cases).
Fertilization is assessed the next day.

Step 6: Embryo Development

Day 2: 2–4 cell stage.
Day 3: 6–8 cell stage (cleavage stage).
Days 5–6: Blastocyst stage (~100 cells) with higher implantation potential.
Not all embryos reach this stage; the best-quality embryos are transferred or frozen.

Step 7: Embryo Transfer

Best embryo(s) are placed into the uterus using a thin catheter.
Quick (5–10 minutes) & painless (similar to a Pap smear).
Day 5 blastocyst transfer increases success rates.
Single Embryo Transfer (SET) recommended for women under 35 to reduce twins or multiples.

Step 8: Luteal Phase & Pregnancy Test

Progesterone supplements support implantation.
Beta-hCG blood test after 10–14 days confirms pregnancy.
Success depends on maternal age, embryo quality, and uterine environment.

Who is IVF Suitable For?

IVF is recommended for:

Blocked or damaged fallopian tubes.
Severe male factor infertility (low sperm count/motility).
Unexplained infertility (after 1 year of trying).
Endometriosis or diminished ovarian reserve.
Genetic disorders (preimplantation genetic testing (PGT)).
Recurrent pregnancy loss or failed IUI.
Same-sex couples, single parents, or surrogacy.
Fertility preservation (freezing eggs or embryos before medical treatments).

IUI vs IVF Success Rate: What to Expect

When considering fertility treatments, understanding success rates is crucial. The effectiveness of both intrauterine insemination (IUI) and in vitro fertilization (IVF) depends on various factors, including age, infertility cause, and treatment cycles.

IUI Success Rates

IUI is generally less invasive but has lower success rates per cycle than IVF.
Live birth (LB) rates for IUI range from 8.8% to 38% per cycle, with cumulative success increasing over multiple cycles (Man et al., 2023).
Ovarian stimulation (IUI-OS) improves outcomes, with research showing a 3-fold increase in live birth and clinical pregnancy rates compared to expectant management (Man et al., 2023).
Most effective in women under 38 years and those with good ovarian reserve.
Cumulative success: Approximately 26–28% after 3 cycles (Man et al., 2023).

IVF Success Rates

IVF is the most effective fertility treatment, offering significantly higher live birth rates per cycle.
Live birth rates for IVF are approximately 32-50% per cycle in women under 35, declining with age (Man et al., 2023).
Women over 38 years benefit more from IVF than IUI, with studies showing double the success rate (Man et al., 2023).
Embryo selection and genetic testing further improve IVF success, reducing miscarriage risk.
Cumulative success: After multiple IVF cycles, the probability of pregnancy exceeds 70% for many patients.

Which Fertility Treatment is Right for You?

Factor	IUI	IVF
Invasiveness	Minimally invasive	More invasive (egg retrieval, embryo transfer)
Success Rates	8.8–38% per cycle26–28% after 3 cycles	32–50% (age-dependent) per cycle >70% after multiple cycles
Cost	Lower per cycle (~$500–$3,000)	Higher (~$12,000–$20,000 per cycle)
Best for	Mild infertility, unexplained infertility, mild male factor	Severe infertility, tubal issues, failed IUI
Multiple Pregnancy Risk	Moderate (if ovarian stimulation is used)	Higher (if multiple embryos transferred)

In sum, IUI is a good first step for younger couples with unexplained infertility or mild male factor infertility. On the other hand, IVF is recommended for women over 38, those with blocked fallopian tubes, poor ovarian reserve, or severe male infertility. Additionally, if IUI fails after 3–6 cycles, switching to IVF is advised.

Take the Next Step – Contact Us Today!

If you’re considering IUI or IVF in the UK, Ovoria can connect you with top fertility clinics to guide you through the process. Contact us today to book a consultation and begin your fertility journey!

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Which is better, IUI or IVF?

IUI is less invasive and cheaper but has lower success rates, making it ideal for mild male factor or unexplained infertility. IVF has higher success rates, is better for blocked fallopian tubes, severe infertility, or failed IUI, and allows for genetic testing. Women over 38 or with low ovarian reserve typically benefit more from IVF.

What is the disadvantage of IUI?

Lower success rates than IVF, especially for women over 35 or those with severe infertility. IUI may require multiple cycles, delaying pregnancy, and has a higher risk of multiples if ovarian stimulation is used.

Can I get twins with IUI?

Yes, IUI increases the chance of twins, especially with fertility drugs. Doctors monitor follicle growth and may cancel or convert the cycle to IVF if too many eggs develop.

References

Cohlen, B., Bijkerk, A., Van der Poel, S., & Ombelet, W. (2018). IUI: Review and systematic assessment of the evidence that supports global recommendations. Human Reproduction Update, 24(3), 300–319. https://doi.org/10.1093/humupd/dmx041

van Loendersloot, L.L., van Wely, M., Limpens, J., Bossuyt, P.M.M., Repping, S., & van der Veen, F. (2010). Predictive factors in in vitro fertilization (IVF): A systematic review and meta-analysis. Human Reproduction Update, 16(6), 577–589. https://doi.org/10.1093/humupd/dmq015

Man, J.K.Y., Parker, A.E., Broughton, S., Ikhlaq, H., & Das, M. (2023). Should IUI replace IVF as first-line treatment for unexplained infertility? A literature review. BMC Women’s Health, 23: 557. https://doi.org/10.1186/s12905-023-02717-1

IUI vs. IVF – Which Fertility Treatment is Right For You?