Multiple pregnancy rates per ongoing pregnancy were 6 % ( 7/121 ) after in vitro fertilisation with single embryo transfer , 5 % ( 5/102 ) after in vitro fertilisation in a modified natural cycle , and 7 % ( 8/119 ) after intrauterine insemination with ovarian hyperstimulation ( one sided P = 0.52 for in vitro fertilisation with single embryo transfer compared with intrauterine insemination with ovarian hyperstimulation ; one sided P = 0.33 for in vitro fertilisation in a modified natural cycle compared with intrauterine insemination with controlled ovarian hyperstimulation ) .