<human>: Provide a brief overview of the text.

So, my girlfriend has accidentally become pregnant last month. (not 'accidentally', but not with any real intention. We weren't trying particularly hard to prevent it, but we hadn't intended for it to happen either). We haven't told anyone yet, but most people we know will be totally ok with it, except my sister.

She has been married for 6 years, and was trying to get pregnant for most of that time. Her and her husband spent around $25k on IVF treatments, and ended up having a very late term stillborn (34 weeks). They tried again and very recently finally had a child. 

I feel like they are quite resentful of the entire process and while they try to hide it, I can see them trying hard not to get upset at larger families etc. They wanted more than one child (they built a 5 bedroom house before they got married), but it's looking very unlikely at this point.

I feel as though I will never be able to comfortably discuss babies/children with my sister, and I fear that it will dig a massive wedge between us.
<bot>: My girlfriend is unintentionally pregnant and I'm worried that it will cause friction between me and my sister who has had severe issues conceiving.