Infertility definition:

A woman of reproductive age who has not conceived after 1 year of unprotected vaginal sexual intercourse, in the absence of any known cause of infertility, should be offered further clinical assessment and investigation along with her partner.

An earlier referral for specialist consultation is offered to discuss the options for attempting conception, further assessment and appropriate treatment where: The woman is aged 36 years or over. There is a known clinical cause of infertility or a history of predisposing factors for infertility.

There are two types of Infertility:
Primary: Couple has never conceived.No conception during first year without contraception.
Secondary: Couple has had at least one prior conception.

Infertility: WHO classification
Ovulation disorders, presenting as menstrual disturbance, are the cause of infertility in around 25% of couples who have difficulty conceiving.

WHO categorizes ovulation disorders into three groups:

Group I ovulation disorders are caused by hypothalamic pituitary failure. This category includes conditions such as hypothalamic amenorrhea and hypo-gonadotrophic hypogonadism. Typically, women present with amenorrhoea (primary or secondary) which is characterised by low gonadotrophins and oestrogen deficiency. Approximately 10% of women with ovulation disorders have a group I ovulation disorder.

Group II ovulation disorders are defined as dysfunctions of the hypothalamic-pituitary-ovarian axis. This category includes conditions such as polycystic ovary syndrome and hyperprolactinaemic amenorrhoea. Around 85% of women with ovulation disorders have a group II ovulation disorder.

Group III ovulation disorders are caused by ovarian failure. Around 5% of women with ovulation disorders have a group III ovulation disorder.


Infertility: Etiology

• 20-40% of couples will have multiple causes.
• It is estimated that infertility affects 1 in 7 heterosexual couples in UK 
• The main causes of infertility in the UK are (percent figures indicate approximate prevalence) 
• Unexplained infertility (no identified male or female cause) (25%) 
• Ovulation disorders (25%) 
• Tubal damage (20%) 
• Factors in the male causing infertility (30%) 
• Uterine or peritoneal disorders (10%). 
• In about 40% of cases disorders are found in both the man and the woman. Uterine or endometrial factors, gamete or embryo defects, and pelvic conditions such as endometriosis may also play a role. 

Factors that increase the risk of infertility:

• Age 
• Stress 
• Poor diet 
• Smoking 
• Alcohol 
• STDs 
• Overweight 
• Underweight 
• Caffeine intake 
• Too much exercise 

Age:

• A woman's fertility naturally starts to decline in her late 20's. 
• After age 35 a woman's fertility decreases rapidly. 
• A woman is born with all the eggs she'll have, and with time, the supply diminishes. 
• The remaining eggs also age along with the rest of the body. 

Age decreases the woman’s ability to conceive by:

• Ability of a woman’s ovaries to release eggs.
• Increased miscarriages.
  

Success Rates

IVF success rates are the percentage of all IVF procedures which result in a favorable outcome. Depending on the type of calculation used, this outcome may represent the number of confirmed pregnancies, called the pregnancy rate or number of live births, called the live birth rate.

Due to advancement in reproductive technology, the IVF success rates are substantially better today than they were just a few years ago.

Live birth rate:

The live birth rate is the percentage of all IVF cycles that lead to a live birth. This rate does not include miscarriage or stillbirth and multiple-order births such as twins and triplets are counted as one pregnancy. A 2012 summary compiled by the Society for Reproductive Medicine which reports the average IVF success rates in the United States per age group using non-donor eggs compiled the following data:

In 2006, Canadian clinics reported a live birth rate of 27%. Birth rates in younger patients were slightly higher, with a success rate of 35.3% for those 21 and younger, the youngest group evaluated. Success rates for older patients were also lower and decrease with age, with 37-year-olds at 27.4% and no live births for those older than 48, the oldest group evaluated. Some clinics exceeded these rates, but it is impossible to determine if that is due to superior technique or patient selection, because it is possible to artificially increase success rates by refusing to accept the most difficult patients or by steering them into oocyte donation cycles (which are compiled separately). Further, pregnancy rates can be increased by the placement of several embryos at the risk of increasing the chance for multiples.

The live birth rates using donor eggs are also given by the SART and include all age groups using either fresh or thawed eggs.
 

Because not each IVF cycle that is started will lead to oocyte retrieval or embryo transfer, reports of live birth rates need to specify the denominator, namely IVF cycles started, IVF retrievals, or embryo transfers. The Society for Assisted Reproductive Technology (SART) summarised 2008-9 success rates for US clinics for fresh embryo cycles that did not involve donor eggs and gave live birth rates by the age of the prospective mother, with a peak at 41.3% per cycle started and 47.3% per embryo transfer for patients under 35 years of age.

IVF attempts in multiple cycles result in increased cumulative live birth rates. Depending on the demographic group, one study reported 45% to 53% for three attempts, and 51% to 71% to 80% for six attempts

Pregnancy Rate:

Pregnancy rate may be defined in various ways. In the United States, the pregnancy rate used by the Society for Assisted Reproductive Technology and the Centers for Disease Control (and appearing in the table in the Success Rates section above) are based on fetal heart motion observed in ultrasound examinations.

The 2009 summary compiled by the Society for Reproductive Medicine included the following data for the United States.
 

In 2006, Canadian clinics reported an average pregnancy rate of 35%. A French study estimated that 66% of patients starting IVF treatment finally succeed in having a child (40% during the IVF treatment at the center and 26% after IVF discontinuation). Achievement of having a child after IVF discontinuation was mainly due to spontaneous pregnancy (42%).