Make room for the other version
Ask what the other person understood before assuming that you are arguing about the same facts. For a message about how to congratulate someone on a pregnancy, use this factual base: name the milestone and, when you know it, the effort or meaning behind it.
Correct the record precisely
Correct only what you can support, acknowledge any real impact, and propose a practical way to prevent repetition. Offer warm recognition and let the recipient decide whether they want a call, visit, gift, or quiet celebration. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Agree on a testable next step
Do not make assumptions about pregnancy, money, relationships, health, or what the achievement should mean next. Follow the person's lead on privacy before sharing their news or photos with anyone else. Do not recruit an audience, publish private evidence, or turn a misunderstanding into a campaign about character.