- Yes the stress/ strain due to any cause may delay periods.So is the case with any major surgery.
- Secondly as per you, she is on contraceptives, making conception impossible.
- In case she had dropped her cotraseptive after her operation-an inter course on the day of expected period is unlikely to cause pregnancy
,unless the irregularity following operation, has shifted her ovulation day.
* In short least possibility of pregnancy, you should wait for menses to come ,& use pregnancy test after 10 days overdue,to rule out your doubt.