Infertility is a medical condition, and a fertility specialist can help with thorough, focused examinations directed at discovering the underlying cause. For every couple that begins an evaluation, about 35% discover that there is an issue with the man which is contributing to the couple’s infertility. 50% is related to female factor while 5% is due to rare causes. The remaining 10% (1 in 5 couples) is due to unexplained infertility despite completing a full infertility work-up.(2)
Infertility is “a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse (and there is no other reason, such as breastfeeding or postpartum amenorrhoea). Primary infertility is infertility in a couple who have never had a child. Secondary infertility is failure to conceive following a previous pregnancy. Infertility may be caused by infection in the man or woman, but often there is no obvious underlying cause.
Cytoplasmic transfer is where the cytoplasm from a donor egg is injected into an egg with compromised mitochondria. The resulting egg is then fertilised with sperm and implanted in a womb, usually that of the woman who provided the recipient egg and nuclear DNA. Cytoplasmic transfer was created to aid women who experience infertility due to deficient or damaged mitochondria, contained within an egg's cytoplasm.
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 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.
When transferring more than one embryo, the risk of pregnancy and newborn complications also increases.1 Among IVF babies, twins are 12 times more likely than singletons to be delivered prematurely, 16 times more likely to be underweight and 5 times more likely to suffer from respiratory complications. Among IVF mothers, mothers of twins are 2.5 times more likely to have pre-eclampsia, over 8 times more likely to have premature preterm rupture of membranes and 4 times more likely to require a Caesarean section.

Your doctor will also monitor whether or not the treatment led to a multiple pregnancy. IVF has a higher risk of conceiving multiples, and a multiple pregnancy carries risks for both the mother and the babies. Risks of a multiple pregnancy include premature labor and delivery, maternal hemorrhage, C-section delivery, pregnancy induced high blood pressure, and gestational diabetes.
Previous tests should be carefully reviewed to ensure that the diagnosis is, in fact, "unexplained," and that no test has been omitted or missed. It may sometimes be necessary to repeat certain investigations. For example, if a previous laparoscopy has been done by a single puncture and reported as normal, it may be necessary to repeat the laparoscopy with a double puncture, to look for early endometriosis. 
Are you infertile, or just having trouble getting pregnant? If you go to the doctor, here’s how a diagnosis of infertility will happen. “Infertility” is a term that describes when a couple is unable to conceive a child after a year of having sex without birth control. In women who are older than age 35, infertility… Read More »How Doctors Diagnose Infertility
SART, in conjunction with, The American Society for Reproductive Medicine (ASRM), has published guidelines for the recommended number of embryos to transfer (add to link). These guidelines are based on SART-sponsored research which continually evaluates success rates around the country.  This helps to determine the optimal number of embryos to transfer, based on specific patient characteristics, like age and history of prior IVF.  Patients may require several cycles of treatment to have a baby. Success rates remain fairly constant over several cycles, but may vary greatly between individuals.  

A body mass index (BMI) over 27 causes a 33% decrease in likelihood to have a live birth after the first cycle of IVF, compared to those with a BMI between 20 and 27.[29] Also, pregnant women who are obese have higher rates of miscarriage, gestational diabetes, hypertension, thromboembolism and problems during delivery, as well as leading to an increased risk of fetal congenital abnormality.[29] Ideal body mass index is 19–30.[17]


Women who switch from IUI to IVF sooner or begin with IVF get pregnant quicker than those who stick or start with IUI. One study found that undergoing immediate IVF resulted in superior pregnancy rates with fewer treatment cycles compared to those who did two rounds of IUI before switching to IVF.  While the immediate IVF group got pregnant quicker, the overall success after up to 6 IVF cycles was similar.

The NHS recommends that, after trying and failing to get pregnant for a year, you should see your doctor; if you are over 35, you should go after six months. Help is out there, if you want it, and takes many forms. West stresses the importance of investigating both the women and the men, "even if they have previously had a healthy sperm analysis because situations and lifestyles can change". There is also the alternative therapy route: acupuncture, hypnotherapy, reflexology, meditation. Or, if all else fails, you could, like me, go for in-vitro fertilisation (IVF).


Intercourse must take place frequently, particularly before and around the time of ovulation, and the couple must have been trying to conceive for at least one year (6 months if the woman is over 35 years old). Using these criteria, about 10-20% of all infertile couples have unexplained infertility. However, the percentage of couples classified as having unexplained infertility will depend upon the thoroughness of testing and the sophistication of medical technology. 
Obviously, if the same couple decides to have more children at age 38, the chances won't be 25% anymore; it is likely that they are about 10%, which translates into a reduced pregnancy chance. This does not mean the couple has become infertile. Since they weren't absolutely fertile at age 32, it is only logical that their pregnancy chances at 38 are so low.
While PGD was originally designed to screen for embryos carrying hereditary genetic diseases, the method has been applied to select features that are unrelated to diseases, thus raising ethical questions. Examples of such cases include the selection of embryos based on histocompatibility (HLA) for the donation of tissues to a sick family member, the diagnosis of genetic susceptibility to disease, and sex selection.[97]
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