Lyric discussion by geordiewatcher 

Cover art for Fur Lined lyrics by How To Destroy Angels

Pretty sure it's about pregnancy.

Echoing could be a sonogram reference or a reference to a test they do on the baby's heartbeat.

When you're pregnant you do discover quite how animal the process of reproduction is.

'everything is right on track' - the baby is measuring as it should.

'this is really happening' - it's amazing how much of a surprise this can be, even when the pregnancy is planned.

and 'pushing through the pain' - labour reference that I think speaks for itself :)

There's probably more layers to it than that, but I think that's the general starting point. At the end of the day she was pregnant when they were putting this CD together, so I take that as evidence for my argument :)