Invitro fertilization or test tube baby involves stimulating the woman's ovaries so that multiple eggs or ova can be retrieved in one menstrual cycle which is then fertilized with the husband's sperms. The fertilized ova are then kept in culture in an incubator where the further steps of embryo development happen. The embryos are then transferred into the uterus at an appropriate time. The overall success rate of ivf is around forty percent.