National and regional usage
In the Nordic countries, letrozole is practically the standard initial regimen used for ovulation induction, since no formulation of clomifene is registered for use there.India banned the usage of letrozole in 2011, citing potential risks to infants. In 2012, an Indian parliamentary committee said that the drug controller office colluded with letrozoles makers to approve the drug for infertility in India. Technique
Although there are many possible additional diagnostic and interventional techniques, protocols for ovulation induction generally consist of:

Determining the first day of the last menstruation, which is termed day 1. In case of amenorrhea, a period can be induced by intake of an oral progestin for 10 days. Daily administration of the ovulation induction regimen, starting on day 3, 4, or 5, and it is usually taken for 5 days. Sexual intercourse or artificial insemination by the time of ovulation. Ultrasonography
During ovulation induction, it is recommended to start at a low dose and monitor the ovarian response with transvaginal ultrasound, including discernment of the number of developing follicles. Initial exam is most commonly started 4–6 days after last pill. Serial transvaginal ultrasound can reveal the size and number of developing follicles. It can also provide presumptive evidence of ovulation such as sudden collapse of the preovulatory follicle, and an increase in fluid volume in the rectouterine pouch. After ovulation, it may reveal signs of luteinization such as loss of clearly defined follicular margins and appearance of internal echoes.
Supernumerary follicles
A cycle with supernumerary follicles is usually defined as one where there are more than two follicles >16 mm in diameter. It is generally recommended to have such cycles cancelled because of the risk of multiple pregnancy (see also the "Risks and side effects" section below). In cancelled cycles, the woman or couple should be warned of the risks in case of supernumerary follicles, and should avoid sexual intercourse or use contraception until the next menstruation. Induction of final maturation (such as done with hCG) may need to be withheld because of increased risk of ovarian hyperstimulation syndrome. The starting dose of the inducing drug should be reduced in the next cycle.Alternatives to cancelling a cycle are mainly:

Aspiration of supernumerary follicles until one or two remain. Converting the protocol to IVF treatment with embryo transfer of up to two embryos only. Selective fetal reduction. This alternative confers a high risk of complications. Proceeding with any multiple pregnancy without fetal reduction, with the ensuing risk of complications. This alternative is not recommended. Lab tests
The following laboratory tests may be used to monitor induced cycles:
Serum estradiol levels, starting 4–6 days after last pill
Adequacy of luteinizing hormone surge LH surge by urine tests 3 to 4 days after last clomifene pill
Post-coital test 1–3 days before ovulation to check whether there are at least 5 progressive sperm per HPF
Mid-luteal progesterone, with at least 10 ng/ml 7–9 days after ovulation being regarded as adequate.