- How did Nessa end up with an accidental pregnancy by Smithy? She states clearly when she confides in Stacey about being "late", that her period is very predictable. She's "regular as clockwork", having a period "every fourth Wednesday" since she was 9. This would mean she would be aware exactly when she was most likely to be ovulating. So why, unless she MEANT to get knocked up, would she have it off with Smithy at the time that she did?
- Maybe she forgot a pill, or ran out. Maybe neither had protection. Maybe what protection they did have broke or didn't work. Maybe he said he'd pull out and didn't. There are literally dozens of ways an accidental pregnancy can occur, even for women with regular periods. As to why she had it off at that time not to put too fine a point on it but that time of the month is typically when a woman is at her most "needy", so to speak. Primal urges and all that. It was probably just a case of "I need this now and you're here so "
Headscratchers / Gavin & Stacey