Watch out for the step that isn't there

One conversation the other night with our pregnant neighbor surprised me. I had asked how many months along she was, and she said eight months. I looked at her profile and commented that she didn't seem big enough. Then I asked when the baby was due -- and she said mid or late October.
( Counting on my fingers )

So I learned that it's better to ask when the baby is due. I wonder if other countries estimate the length of pregnancy differently.