Did an unplanned pregnancy prompt the argument that left R&B crooner Chris Brown facing felony assault charges?

Just days before the alleged assault that resulted in serious injuries for bruised and bloodied pop star Rihanna, the 21-year-old hitmaker visited an OB-GYN at Cedars-Sinai Medical Center in Los Angeles because she feared she was pregnant with Chris’ baby, snitching celebrity insiders blab in the March 9 edition of Star Magazine.

A shaken Rihanna scurried into the clinic dressed in black with her eyes shield by large sunglasses.

“She was extremely fidgety. She seemed totally uncomfortable,” an eyewitness at the doctor’s office reveals.

Pals say Rihanna feared a pregnancy would further strain her already tenuous relationship with the 19-year-old “Run It” star.

“She was scared he would react badly,” says an insider.

Rihanna told friends: “All I could think was, ‘Oh, my God, I could lose the baby!’”