Besides -- the risk we're talking about here isn't just to the baby, it's to the mother. The miscarriage would endanger Deanna's life if it didn't happen under controlled conditions with immediate medical care available. Basically what Deanna was doing was tantamount to going on a suicide mission.
Sorry, but that's just a horrible exaggeration. I'm not saying that an uncontrolled miscarriage isn't dangerous - far from it. But it's definitely not the same as "tantamount to going on a suicide mission". I mean we're not talking about health care in a less developed country here, but medical care in the 24th century with ways to diagnose problems earlier than nowadays. I wonder for example why Ree didn't use that subdermal diagnostic gadget of his from the start - then he'd have been alerted to any problems immediately, and I don't think Deanna would have been opposed to that.
But no, he's got to suggest a hysterectomy...
I guess Beverly is lucky to be CMO herself, because while there are no immediate dangers in her pregnancy, just her age could be considered a risky thing - especially given that the Enterprise is engaged in direct combat and the CMO is definitely more required to be at her post than some Chief Counselor (except if there suddenly happens to be a First Contact-situation...)...
I'm not trying to diminish the fact that Deanna's at risk here, but even nowadays women aren't (or shouldn't be) encouraged to undergo an abortion *here and now* once they get the diagnosis that the fetus isn't viable. They are given time to think and decide. That's my main criticism here, that she wasn't even given that time of grace.
She did have the same right Data won there. She could've resigned her commission and therefore been freed from the obligation of following orders. But as long as she's a commander in Starfleet, she is subject to obeying decisions made on her behalf by others.
I'd agree if all other possibilities were out of the question - but that wasn't the case here, as evidenced by the sudden suggestion of stasis, or the implantation of that diagnostic thing. I realize it's not a treatment, but at least it buys some time and reduces the imminent danger. And time is all that was required here.