Baby For the Mosaic Med Chief by Aurelia Skye

She was matched to another Mosaic but claimed by the Med Chief.
Briana Willis reluctantly accepts her proxy match with a Mosaic commander, but when she reports to MedBay for her genetic modification injection, the Med Chief insists she’s his mate. She seizes the opportunity as a way to escape both matings, planning to ditch the chief later, but she forms an unexpected connection with Quillin. Could his insistence of a Mating Flare be real, and she’s his destined mate?
Once she accepts the truth and his claiming, they still have to convince the Faction, which is difficult since they’re wanted fugitives. Can they enact change to years of tradition, or will their bond be permanently severed by Quillin’s forced participation in a blood fight when Commander Zartik demands revenge?
Seven years ago, the Faction agreed to save Earth from the vorathan invasion in exchange for Earth women giving them one year of proxy rights to act as a surrogate, since the aliens of the Faction faced a dwindling population. With the vorathans feared throughout the galaxy as bloodthirsty, vicious marauders, the Earth’s government agreed.
That doesn’t mean the women did.