In the manner of explaining why she lost faith in the pro-life movement, Libby Anne says this sort of argument made an impression on her:
Due to hormone imbalances, genetic anomalies, and a number of unknown factors, between 50 percent and 75 percent of embryos fail to implant in the uterus and are passed with the monthly menstrual flow. If we agree with pro-life advocates that every embryo is as morally valuable as an adult human, this means that more than half of humans immediately die. This fact provides pro-life advocates with an opportunity to follow through on their convictions. Surely, a moral response to a pandemic of this magnitude would be to rally the scientific community to devote the vast majority of its efforts to better understanding why this happens and trying to stop it. Yet the same pro-life leaders who declare that every embryo is morally equivalent to a fully developed child have done nothing to advocate such research. … Even if medicine could save only 10 percent of these embryos — and we don’t know because no one has cared enough to ask — it would be saving more lives than curing HIV, diabetes, and malaria combined. One could say that this massive loss of human life is natural, and therefore, humans are under no obligation to end it. But it is not clear why the same argument could not be used to justify complacency in the face of AIDS, cancer, heart disease, and other natural causes of human death.
The above paragraph is from Jonathan Dudley’s Broken Words: The Abuse of Science and Faith in American Politics. I think this is an interesting argument; it can be stated more formally like this:
 If the pro-life movement were morally consistent, it would advocate for research to mitigate the loss of human life naturally lost in the womb [premise].
 The pro-life movement fails to do this [premise].
 Therefore, pro-life movement is morally inconsistent [MT 1, 2].
Suppose this is right. Then the pro-life movement should make an effort to advocate for research to be morally consistent. But so what? That just says something about what the pro-life movement fails to do; it doesn’t say anything about the truth of what the pro-life movement believes about the human embryo, which is what ultimately matters.