I’m about as pro-choice as they come (lol up my various articles on this topic of you don’t believe me), and I’m also a lawyer, and I’ve gotta say I’m very skeptical of this claim.
For one thing, how are we defining “involuntary”? Maybe you could claim that a pregnancy that results from rape causes involuntary servitude, but not from consensual sex.
And how are you defining “servitude”? Typically it meant you provide some value in the form of labor to some individual or individuals, but without compensation. But who is the master in this master-servant relationship, and where is the evidence that the labor being provided is typically compensated?