INTRODUCTIONThe development of assisted reproductive technologies has revolutionized the treatment of Infertility. The 1 st IVF baby Louise Brown was born in 1978 by the pioneering efforts of Prof Edwards and Steptoe for which Prof Edwards was honoured with the Nobel Prize in medicine in 2010. The first IVF was natural cycle IVF in which one oocyte during natural cycle was retrieved. In natural cycle of a female one mature oocyte is released so that the rate of cancellation of cycle was high and success was less. 1In order to overcome that controlled ovarian hyper stimulation was introduced to facilitate multifollicular development and hence multiple oocyte and availability of more than one embryo for transfer. But this procedure can cause complication like OHSS, higher order multiple pregnancy and increased cost also. Many oocytes are discarded during various stages of laboratory procedures of IVF.2 The primary aim of IVF treatment is to achieve a live birth at term. So the critical question remains that how many mature oocytes per stimulation cycle is most suitable to achieve a live birth with low risk of complications.Many studies have focused on the relation between oocyte number and clinical pregnancies and have shown conflicting results. Some studies have analyzed the relation in between number of oocytes and live birth rate in fresh transfer.1 Our study is to determine the association in between the number of oocytes retrieved and a live birth ABSTRACT Background: There is a strong association between the number of eggs and clinical pregnancy rates in IVF. But a few studies have shown conflicting results. Aim was to determine the relation between number of mature eggs retrieved and live birthrate in one complete IVF cycle (fresh and all frozen transfers included) and hence determine the optimum number of oocytes. Setting private IVF centre doing around 2000 cycles per year. Methods: Retrospective analysis of 1140 infertile women between 20 and 45 years who underwent self-stimulation IVF in our centre, primary outcome studied was cumulative live birth rate in one complete IVF cycle. Secondary outcome was the number of cases of moderate and severe OHSS. Results: Maximum LBR in patients where 10-15 egg were retrieved in fresh embryo transfer and cumulative LBR was maximum when more than 15 eggs were retrieved. No case of severe OHSS and one case of moderate OHSS in the group where more than 15 eggs were retrieved. Conclusions: The percentage of live birth increases with increasing number of mature eggs in IVF treatment. The incidence of OHSS was negligible.