Luteal support
Luteal support is the administration of medication, generally progesterone, progestins, hCG or GnRH agonists, to increase the success rate of implantation and early embryogenesis, thereby complementing and/or supporting the function of the corpus luteum. It can be combined with for example in vitro fertilization and ovulation induction. Progesterone appears to be the best method of providing luteal phase support, with a relatively higher live birth rate than placebo, and a lower risk of ovarian hyperstimulation syndrome (OHSS) than hCG. Addition of other substances such as estrogen or hCG does not seem to improve outcomes. Progesterone and progestins. The  live birth rate is significantly higher with progesterone for luteal support in IVF cycles with or without intracytoplasmic sperm injection (ICSI). Co-treatment with GnRH agonists further improves outcomes, by a live birth rate RD of +16% (95% confidence interval +10 to +22%). Routes and formulations. There is no evidence of any route of administration of progesterone or progestins being more beneficial than others for luteal support. The main ones are: Time of initiation. The time for beginning luteal support can be put in relation to various events: Duration. Luteal support given for a shorter duration than 7 weeks results  in an increased risk of miscarriage in women with a dysfunctional corpus luteum (as can be diagnosed by blood tests for endogenous progesterone). In general, however, luteal support can safely be discontinued at the time of a positive pregnancy test (approximately 2 weeks after fertilization). Other substances tested in luteal phase. The addition of estrogen or hCG as adjunctives to progesterone do not appear to affect outcomes pregnancy rate and live birth rate in IVF. In fact, luteal support with human chorionic gonadotropin (hCG) alone or as a supplement to progesterone has been associated with a higher risk of ovarian  hyperstimulation syndrome (OHSS). Low molecular weight heparin as luteal support may improve the live birth rate but has substantial side effects and has no reliable data on long-term effects. Glucocorticoids such as cortisol has limited evidence of efficacy as luteal support.