Induction of follicular growth and ovulation with urinary and recombinant gonadotrophins.

Gonadotrophins have been used since the 1930s. By the 1990s, a pure biological extract of FSH was obtained. The increase in the demand for new assisted reproduction techniques led to the creation of recombinant FSH, 99% pure and highly consistent between batches, with no LH activity, and a high specific activity. In gonadotrophin protocols, follicular growth can be monitored with regular ultrasounds and/or hormonal testing, mainly oestradiol in the follicular phase. In assisted reproduction the adoption of ovulation induction strategies with GnRH analogues, control the endogenous secretion of LH, avoiding cancellations due to an early LH surge, and premature ovulation. Depending on the moment when pituitary suppression starts, there are short, ultra-short and long protocols The use of long protocols not only increases pregnancies and live births, it also allows an easier programming and simplifies IVF treatments. Ovarian stimulation entails some risks such as ovarian hyperstimulation syndrome and multiple pregnancies that can be avoided in many cases with an accurate prediction and an active prevention.