Intrauterine insemination is effective for some cases with sperm quality problems. However, if the total motile count at the time of insemination (after processing) is less than 5 million, chances for pregnancy with IUI are much lower. If the total motile sperm count is below 1 to 5 million, success is unlikely. Therefore, in vitro fertilization with ICSI (injecting sperm into eggs) is usually done for couples with sperm numbers this low. Five million is a big number, and sometimes patients say; “why won’t it work if there’s 5 million – that’s a lot, and doesn’t it just take one to do the job?

• The problem is that with low counts, motility and morphology scores there are often issues with the biochemical and molecular ability to be able to fertilize an egg
• In the end, it is not the numbers that are important, it is the ability of the sperm to function properly in a biochemical process
• Low semen analysis numbers suggest the sperm may not be biochemically competent

• Biochemical and molecular sperm defects can almost always be overcome by injecting individual sperm into the eggs
• In this sense, men are just DNA donors. If we pick up sperm and inject into eggs and get fertilization – their reproductive job is done
• If the sperm are not biochemically capable of fertilizing eggs, putting them higher in the uterus with IUI will not solve the fertility problem. Therefore, with severe sperm problems chances for IUI success are very low.

IUI for unexplained infertility

• Clomid plus IUI has about an 8% per month chance for successful pregnancy
• Injectable FSH products (“injectables”) plus IUI give about 12% success per month
• These statistics hold for about 3 months and after that success rates are much lower
• Usually by that point couples move on to IVF if IUIs have not been successful
• Chances for success with IVF are very good in young women regardless of whether IUIs have worked or not

IUIs and female age

IUI success rates over age 40

• It is well known that chances for success with IUI in women over age 40 are much lower. The results of several studies have been consistent in showing this.
• Many couples with a female partner over 40 will move fairly quickly to IVF treatment
• Two issues pushing for this are the low success rates with IUIs over 40 and the understanding that there is an ever-shortening fertility window
• The table above shows results from one large study of IUIs using Clomid
• Most studies have shown a success rate (delivery of a baby) at age 41 of about:
  • 1-2% per month with Clomid + IUI
  • 2-4% per month with injectables + IUI
  • IVF success rates are much higher – about 20% at age 41 in our IVF program

IUI and endometriosis

• A pregnancy rate of 6.5% for women with endometriosis vs. 15.3% per cycle for unexplained infertility
  • Reference: Nuojua-Huttunen et al., Intrauterine insemination treatment in subfertility: an analysis of factors affecting outcome. Human  Reproduction 1999.
• A pregnancy rate of 5.6% for women with advanced endometriosis vs. 22.7% per cycle for mild endometriosis vs. 25.7% for no endometriosis
  • Reference: Prado-Perez et al., The impact of endometriosis on the rate of pregnancy of patients submitted to intrauterine insemination. Fertility and Sterility,2002.
• Pregnancy chances with insemination for natural cycle IUIs (no drugs) with endometriosis are about 2% per cycle vs. 11% with injectables plus IUI for endometriosis

First time IUI success rate

• First time IUI success rates are somewhat higher than for additional attempts
• If insemination is increasing the efficiency of the fertility process for a couple, we expect a pregnancy fairly soon
• The average success rate per try drops with each attempt until 3 tries are done
• IUI success after 3 cycles is much lower
• Another way to say it – if insemination is going to work it will be in the first 3 tries
• Several studies have shown that 90% of IUI successes are in the first 3 cycles

• After several failed IUIs, many couples believe that their fertility problem is so severe that they will never get pregnant
• However, their problem was not circumvented with insemination but was with IVF
• Some couples are very inefficient reproducers with sex and with IUIs, but very efficient reproducers with IVF
• IVF bypasses many problems that IUI cannot

IUIs vs. IVF – when to move on?

• The short answer is to move on to IVF after 3 failed IUIs
• If the fertility problem is due to a lack of ovulation, maybe try a few more
• If the female is under 30 and ovarian reserve is good, maybe try a few more
• Costs of fertility treatments are a big factor in deciding when to move beyond IUI
• If the female is 40 or older, or ovarian reserve low, consider moving to IVF sooner
• In vitro fertilization is the next step after IUIs – with a much higher success rate

• Since so much is left to nature with IUI, there is not much that we can improve on
• The sperm must swim to the end of the fallopian tube where the egg should be
• The egg has to be able to ovulate from the ovarian follicle and be picked up by the tube
• The sperm must find and fertilize the egg
• These steps are forced with IVF but are left to nature with IUI. Hence the much lower success rates for IUI compared to IVF
• More details about IVF changes and improvements in success over the years

Success rates of regular intercourse vs. IUI

• A couple that has been trying for a year and a half and does not have tubal problems, sperm problems or endometriosis has about a 2% chance per month (over the next year) of getting pregnant from regular intercourse
• If a similar couple does Clomid with IUIs, the expected success rate is 10% per month for up to 3 months

IUI success rates and PCOS, polycystic ovarian syndrome

• Women with polycystic ovarian syndrome, PCOS have significant ovulation problems
• The first-line treatment is usually inducing ovulation with medications
• If the woman responds properly to the ovulation inducing drugs, success rates with timed intercourse are pretty good
• However, IUIs are also used in these couples with an even higher success rate Clomid or Femara plus IUI with PCOS: 15-20% success per month (for 3 months)
  • Injectables plus IUI with PCOS: 20-25% success per month (for 3 months)
  • However, multiple pregnancy risks are high with injectables for PCOS

Should one or two inseminations be done per cycle?

• Several studies have addressed this question
• Some studies show no improvement in success with 2 inseminations done on sequential days compared to 1 well-timed IUI
• Others show higher success if 2 inseminations are done on back to back days
• One explanation for the different findings is that if single inseminations are not ideally timed for ovulation, success rates could improve with a double insemination protocol.
• Then,at least one of the insems might be properly timed.
• Most fertility specialists believe that 1 well-timed IUI is sufficient