Perhaps if you had said, "we're expecting" rather than "we're pregnant," they may have reacted differently as they are probably dumbfounded that their son is pregnant.

Are you close with your SIL? Maybe she can shed some light on her parents' reaction.
My brother's wife and I have a great relationship and through the years, I have helped her interpret some of my mother's more crazy comments/reactions/demands. And I have straightened my mother out on certain occasions.
Different cultures, different generation etc.

Oh my, I feel awful for your DH. How completely disappointing! I mean, it doesn't take much to muster some congratulations and hugs.

I wouldn't write them off just yet. Tiny babies have quite a hold on people sometimes. It could just be they need to let it sink in.

Does your DH's sister have any insight as to why they'd react that way?

I would ask your husband to call them and ask them why they reacted the way they did. They might have a reason.

My mom reacted similarly, and then throughout my pregnancy, she barely talked to me. Nearly every phone call went through my husband, and I'm talking about calls like "what time should we come for Christmas," calls (not pregnancy-related). I believe it was because her first baby died within just hours after being born (45+ years ago), and she was concerned we'd have the same issues. But she wouldn't talk about it. By the time our baby was a couple weeks old, she was fine.

People are weird. Who knows why your inlaws reacted like that. But please, do have your husband (or you can) ask why. I think you'll feel better knowing.

Sounds to me like maybe they are still hoping for the ex girlfriend....

I think you need to encourage DH to call his parents and explain his sadness, see if there is any reason why they were so cold.

Not being over the top excited at your news doesn't equal they will be bad grandparents.
I can't think of a single child who has asked how did nana and poppa react to you being pregnant with me ( I'm sure some internet smart ass will pop up to claim differently).

Most likely, they are worried about being too excited, they are from a different generation when pregnancy news was handled differently.

Is it early? My ILs thought it was bad luck that we were telling people (even though it was just family) before 20 weeks, so they were happy for us but concerned. That was kind of cultural though, so I could keep it in context and not take it personally.

If that's not it, then I'd just follow your husband's lead on how he wants to deal with it. My own sister had a weird, non-reaction when I had my first, but has since really warmed up and actually is the most engaged of the uncles & aunts. Some people have their own issues re pregnancy & babies, so give it time and let them come back to you with expressions of interest/excitement. If they don't, then I'd follow their lead and only give them as much information as they seem interested in. It's disappointing for sure, but ultimately they loose more than anyone if they opt out of grandparenting.

My own parents reacted this way. I was 38 at the time, and I think they had just decided and accepted that I would never have kids, so they were in shock. They came around.

I'm sorry, OP. I think your husband needs to call and say that you were both hurt and disappointed. Better to "air this" now than have it be a point of resentment for years and years.

Your in-laws sound like sucky people, and you can't change that. Be happy in your own joy and in the joy of your family. If it turns out that your in-laws don't want to be involved in their grandchild's life, that's their loss.

I should add too, which made it worse, their neighbor just got a puppy and they lost their minds over it when we first got there. Like took pictures and gushed and laughed and said how cute it was. So I know they are capable of some sort of a reaction! And it's been a week almost, they still haven't called or said anything. MIL texted on Halloween and asked if we had a lot of trick or treaters. ??

Wow, that's crazy. I guess you know how they feel. Good to know now rather than later.

I'm so sorry OP, but I have no explanation.

That's super weird.

DH and I have been married for 3 years, together for 10. In-laws have always been standoffish with me. I think they still hold out hope he will end up with his college girlfriend.

We're pregnant and shared the news at the safe point in person. They literally sat there not reacting. When I told my dad and family, I was worried the police would be called from all the shrieking and hugs! I didn't expect them to do flips around the living room but we thought they'd be a little excited? I don't know why this is bothering me so much. DH is crushed. He has a younger sister that lives out of state that was excited to hear the news. This wasn't an accident or a surprise either. We have been TTC for months now.

It doesn't matter in the long run but did you have anyone have no reaction to your announcement? Any reason you thought why? I think I'm just bummed because I don't have a mother (passed away when I was little) and I thought MIL would have advice or tips or something. They both just looked at each other and said dinner would be in 15 mins...? We ate in silence basically and then headed home.