“…Possible reasons for the differences include: increased gonadotrophin requirement during ovarian stimulation [8,10,16,23,24], fewer retrieved oocytes [8,10,16], decreased serum estradiol concentrations [9,14,24], increased cycle cancellations [8,[12][13][14]25] and lower fertilisation rates [13,16,24]. In contrast, other studies have found that obesity exerts no effect on the need for gonadotrophin [11,12,15], the fertilisation rate [15,22,23,25] and does not affect the peak estradiol levels [16,23,25,26]. In addition, obese women who conceive following IVF have been found to be at an increased risk of spontaneous abortion [8,15,18,27] and a significant risk of obstetrical complications [14].…”