The embodiments herein relate to a method in a base station (101) for transmitting a transport block to a user equipment (105) in a communications network (100). The transport block comprises a plurality of bits. The base station (101) selects (203a, 203b, 401) a transport format. The base station (101) dynamically selects (204a, 203b, 402) a first redundancy version parameter based on a decoding performance for the transport block. The base station (101) transmits (205a, 204b, 404) the transport block comprising the plurality of bits distributed according to the dynamically selected first redundancy version parameter and according to the selected transport format in a first transmission to the user equipment (105).