The author didn't note that female rape may also result in pregnancy. If the captives are long term like POW's the victim will inevitably become even more physically compromised and the spectre of delivering a baby under those circumstances is ghastly.
If she's released, escapes or is rescued fairly soon then there's abortion and treatment for sexually transmitted diseases to consider.
Male rape (sodomy) has fairly awful physical consequences as well in that the human colon is inarguably 'exit only.' Gay men go to considerable lengths to circumvent biological limitations yet physical and microbial damage in that population remains high. But at least they can't get pregnant.
FWIW, my background is molecular/microbiologist but I don't consider myself an expert anymore.