Preimplantation genetic screening (PGS) or preimplantation genetic diagnosis (PGD) has been suggested to be able to be used in IVF to select an embryo that appears to have the greatest chances for successful pregnancy. However, a systematic review and meta-analysis of existing randomised controlled trials came to the result that there is no evidence of a beneficial effect of PGS with cleavage-stage biopsy as measured by live birth rate.[81] On the contrary, for women of advanced maternal age, PGS with cleavage-stage biopsy significantly lowers the live birth rate.[81] Technical drawbacks, such as the invasiveness of the biopsy, and non-representative samples because of mosaicism are the major underlying factors for inefficacy of PGS.[81]
Success varies with many factors. The age of the woman is the most important factor, when women are using their own eggs. Success rates decline as women age, specifically after the mid-30’s.  Part of this decline is due to a lower chance of getting pregnant from ART, and part is due to a higher risk of miscarriage with increasing age, especially over age 40.  
With the exception of severe male infertility, 70% of the oocytes will become fertilized. In the case of severe male infertility, ICSI (pronounced ick-see) may be used to fertilize the eggs, instead of simply placing them in a culture dish. With ICSI, the embryologist will choose a healthy-looking sperm and inseminate the oocyte with the sperm using a special thin needle.
^ Lasa, JS; Zubiaurre, I; Soifer, LO (2014). "Risk of infertility in patients with celiac disease: a meta-analysis of observational studies". Arq Gastroenterol. 51 (2): 144–50. doi:10.1590/S0004-28032014000200014. PMID 25003268. Undiagnosed celiac disease is a risk factor for infertility. Women seeking medical advice for this particular condition should be screened for celiac disease. Adoption of a gluten-free diet could have a positive impact on fertility in this group of patients.(...)According to our results, non-diagnosed untreated CD constitutes a risk factor significantly associated with infertility in women. When comparing studies that enrolled patients previously diagnosed with CD, this association is not as evident as in the former context. This could be related to the effect that adoption of a gluten-free diet (GFD) may have on this particular health issue.
"Demographers tend to define infertility as childlessness in a population of women of reproductive age," whereas "the epidemiological definition refers to "trying for" or "time to" a pregnancy, generally in a population of women exposed to" a probability of conception.[8] Currently, female fertility normally peaks at age 24 and diminishes after 30, with pregnancy occurring rarely after age 50.[9] A female is most fertile within 24 hours of ovulation.[9] Male fertility peaks usually at age 25 and declines after age 40.[9] The time needed to pass (during which the couple tries to conceive) for that couple to be diagnosed with infertility differs between different jurisdictions. Existing definitions of infertility lack uniformity, rendering comparisons in prevalence between countries or over time problematic. Therefore, data estimating the prevalence of infertility cited by various sources differs significantly.[8] A couple that tries unsuccessfully to have a child after a certain period of time (often a short period, but definitions vary) is sometimes said to be subfertile, meaning less fertile than a typical couple. Both infertility and subfertility are defined as the inability to conceive after a certain period of time (the length of which vary), so often the two terms overlap.

Ovulation induction (in the sense of medical treatment aiming for the development of one or two ovulatory follicles) is an alternative for women with anovulation or oligoovulation, since it is less expensive and more easy to control.[7] It generally involves antiestrogens such as clomifene citrate or letrozole, and is followed by natural or artificial insemination.
Endometriosis implants are most commonly found on the ovaries, the Fallopian tubes, outer surfaces of the uterus or intestines, and on the surface lining of the pelvic cavity. They also can be found in the vagina, cervix, and bladder. Endometriosis may not produce any symptoms, but when it does the most common symptom is pelvic pain that worsens just prior to menstruation and improves at the end of the menstrual period. Other symptoms of endometriosis include pain during sex, pain with pelvic examinations, cramping or pain during bowel movements or urination, and infertility. Treatment of endometriosis can be with medication or surgery.

Unlike the simpler process of artificial insemination -- in which sperm is placed in the uterus and conception happens otherwise normally -- IVF involves combining eggs and sperm outside the body in a laboratory. Once an embryo or embryos form, they are then placed in the uterus. IVF is a complex and expensive procedure; only about 5% of couples with infertility seek it out. However, since its introduction in the U.S. in 1981, IVF and other similar techniques have resulted in more than 200,000 babies.
Fertility preservation for cancer or other health conditions. If you're about to start cancer treatment — such as radiation or chemotherapy — that could harm your fertility, IVF for fertility preservation may be an option. Women can have eggs harvested from their ovaries and frozen in an unfertilized state for later use. Or the eggs can be fertilized and frozen as embryos for future use.
Luteal support is the administration of medication, generally progesterone, progestins, hCG, or GnRH agonists, and often accompanied by estradiol, to increase the success rate of implantation and early embryogenesis, thereby complementing and/or supporting the function of the corpus luteum. A Cochrane review found that hCG or progesterone given during the luteal phase may be associated with higher rates of live birth or ongoing pregnancy, but that the evidence is not conclusive.[79] Co-treatment with GnRH agonists appears to improve outcomes,[79] by a live birth rate RD of +16% (95% confidence interval +10 to +22%).[80] On the other hand, growth hormone or aspirin as adjunctive medication in IVF have no evidence of overall benefit.[30]