Upvote:2
Yes, you need to obtain what is called Advanced Parole.
Make sure you don't have any bars to reentry before leaving because Advance Parole does not guarantee you will be let in, IF it is discovered that you have some ineligibility issues (e.g. you previously overstayed for more than six months).
Since you do not even know what Advance Parole is, I will take it you have very little knowledge of the immigration process and probably have a lawyer handling your adjustment of status petition. I advise you contact him to review BEFORE you leave.