Hi,
Welcome to ehealthforum.
You can become pregnant before or after your surgery. If you have definite symptoms suggesting pregnancy then you should consider getting yourself examined by your gynecologist for confirmation of the pregnancy. The symptoms suggesting pregnancy include: fatigue, nausea, constipation, sore breasts, sensitive nipples, increased sleep, hunger and tiredness, mood changes, headaches, back pain, lower abdominal cramps, depression, increased frequency of urine, altered menstrual bleeding, spotting etc.
Take care.