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(ART), and IUI is usually a couple’s first line of treatment, with three to six treatment cycles being the standard before IVF is recommended. The success rates for IUI (with Clomid) and IVF are very similar; however, trying naturally is more successful than either for couples with unexplained infertility!

Intra-Uterine Insemination (IUI)

The low cost and low impact of IUI are significant advantages, and it’s especially appropriate for couples that have cervical mucus issues (about 15% of infertility cases). IUI is usually the treatment option when:

  • Regular ovulation is a problem
  • A couple has “unexplained infertility”
  • The man has impotence or premature ejaculation issues
  • A woman is using donor sperm

Two Cochrane reviews suggest there isn’t enough evidence that either IUI or IVF is more effective than natural sexual intercourse in couples with unexplained sub-fertility. NICE (National Institute for Health and Care Excellence) has recommended that IUI is no longer offered and suggests a policy of two years of sexual intercourse followed by IVF. Given the emotive (and financial) issues involved, this recommendation has generated a lot of debate, and only 4% of UK gynaecologists have followed it.


  • At least one Fallopian tube is patent (functional), and IUI only proceeds when the tube is healthy on the side of ovulation
  • That sperm numbers and quality are sufficient for natural pregnancy


IUI is performed either in a natural cycle or with stimulation to increase egg numbers or trigger ovulation.

  1. Without drugs: The couple have ovulation predictor kits, and IUI is just before the predicted ovulation (usually days 12 to 16)
  2. With drugs, either:
  • Clomiphene citrate (Clomid) early in the cycle to induce ovulation
  • FSH stimulates multiple follicles to maturity, with follicle tracking to measure when the eggs are mature. Human chorionic gonadotropin (hCG) then stimulates the release of the eggs, and IUI follows

Procedure and outcomes

The man provides a fresh sperm sample on the day; this is then “washed”, and all rapidly moving sperm are collected and inserted into the uterus. The success rates for IUI are: ii

  • 15.8% for women aged under 35
  • 11.0% for women aged between 35-39
  • 4.7% for women aged between 40-42
  • 1.2% for women aged between 43-44

Natural Cycle IVF

The original IVF cycles that led to Louise Brown’s birth in 1978 were “natural”, unstimulated protocols, and despite most IVF involving drugs increasing egg numbers for retrieval, it’s still a viable option. It can also be the preferred option for women who are given little chance of success with stimulated cycles as it maximises their strengths rather than forces a tired system.

  • There’s no down-regulation or stimulation in the follicular phase
  • The ovaries are scanned every other day from the end of the period until the dominant follicle reaches 17mm, and the endometrium is over 8mm thick
  • One injection of GnRH antagonist about 36 hours before egg collection to help mature the follicle and prevent it from rupturing prematurely
  • A single egg is collected from the dominant follicle
  • The egg is fertilised
  • The embryo is incubated and usually transferred 3-5 days later
  • Progesterone pessaries may be given from the embryo transfer until the 12th week

Advantages of the natural cycle

  • Only one drug (the GnRH antagonist) is part of the treatment
  • There’s no risk of ovarian hyper-stimulation syndrome (OHSS)
  • The cost of treatment is much lower without stimulation drugs
  • Back-to-back cycles are possible
  • This approach is often successful for women in their 40s as it takes advantage of the body’s natural selection of the most viable egg (to reduce the chances of genetic issues)