Khloé Kardashian is supporting Kim Kardashian West through her struggle to get pregnant.

The 34-year-old reality TV star, who has 19-month-old daughter North with husband Kanye West, recently admitted their bid to have a second child has been ''challenging,'' and has now turned to her younger sister, 30, who was unable to conceive with her estranged husband Lamar Odom, for advice.

A source said: ''Khloé is the only one in the family that Kim really can turn to for advice.

''Khloé just gets what she is going through and how hard it is.''

The insider told gossip website RadarOnline.com that Kim is trying not to worry even though she and Kanye, 37, ''have been trying for several months now because Kim wanted the baby to be out in time for summer.''

The source added: ''Kanye keeps telling her that it will happen and not to worry, but she is worrying. She is beginning to think that there is something wrong with her.''

The couple reportedly haven't ruled out fertility treatments if they can't conceive naturally.

The source said: ''Kim is now exploring several options, such as surrogacy, in vitro fertilisation and other types of advanced insemination procedures.''

The 'Keeping Up with the Kardashians' star previously called North her ''miracle baby,'' as four doctors once told her she would never be able to get pregnant.