Thanks for your query,
To answer your query, we will need details of operation. What was exactly done and what structures were removed. If i presume it was done for ovarian cyst/tumour which is a common cause of laparotomy
at this time of pregnancy
. In this case also even if one ovary or its part is retained during operation, then chances of pregnancy is there. Go through the operation notes.
Best of luck.
Hope it helps..