Pro-choicers regularly accuse pro-lifers of favoring policies that increase abortions by (a) being one-issue voters who care only about laws restricting abortion (and politicians who will appoint, confirm, or be judges who will move things back in a direction that allows more of such restrictions), (b) actively opposing laws and policies that will decrease the number of abortions, or (c) promoting policies that will actually increase the number of unwanted pregnancies.
I'm sure there are people who are inconsistent in applying their pro-life principles by doing such things, but there are plenty of unfair ways to make such arguments, particularly when they ignore other beliefs held by many pro-life people that make their position fully consistent.
For example, contraception decreases the number of unwanted pregnancies, it is argued, and therefore pro-lifers who want to decrease the number of abortions ought to promote contraception. So the charge is that pro-lifers who oppose contraception are thus inconsistent.
It doesn't take much reflection to see that this argument is patently unfair to some pro-lifers. Consider the following proposal. Let's kill everyone on the planet. That would surely decrease the number of unwanted pregnancies. But no pro-lifer would advocate it, because it would be wrong to decrease the number of unwanted pregnancies by using such a method. Now no one is offering that proposal, but consider the proposal in question. The suggestion is that by promoting contraception we would decrease the number of unwanted pregnancies, and therefore we would decrease the number of abortions. You might think that this proposal is much better than simply killing everyone on the planet, which would also produce that same goal. In fact, it is. I'd be shocked to find anyone, pro-life or not, who wouldn't agree. But a proposal doesn't have to be as bad as killing everyone on the planet to be immoral, and at least one possible view would still consistently hold to pro-life views on abortion and anti-contraception views.
Some pro-lifers are simply opposed to contraception in principle. They think it's immoral. They surely don't think it's as immoral as wiping out all human life. But they do think it would be wrong to participate in it or promote it, and supporting policies that attempt to get more people to use contraception would indeed participate in and promote contraception. To such a person, it doesn't matter if they are opposing a policy that would decrease unwanted pregnancies. Decreasing unwanted pregnancies is a good thing, since it removes the occasion in which some people will do something immoral. But we shouldn't do something immoral ourselves in order to remove the situation where someone else will be tempted to do something immoral. So such a person is consistent with pro-life principles while opposing policies that promote contraception, and it's extremely unfair to such a person's actual views to accuse them of inconsistency before exploring what views they might have for resisting the promotion of contraception.
Similarly, if someone thinks it's immoral to promote economic policies that will put more people in better situations and thus remove some of the concerns that lead to abortions, then they should oppose those policies. Suppose the person is a pro-life economic libertarian of an extreme enough sort that they think welfare amounts to stealing, for example. They won't see the good consequences of welfare for those who are tempted to have abortions as good enough to overcome the wrongness of stealing from one group of people to help others. Preventing one bad situation that prevents a temptation for an immoral act is surely a good thing, but if it means adopting an economic policy that one considers immoral, it might eliminate that method, depending on what moral theory we're working with and how one sorts through potentially conflicting moral principles.
Now the argument is much better when directed against someone who doesn't see the policy in question as being intrinsically wrong but just sees it as a bad idea. Most economic conservatives don't oppose welfare programs at any level. Many pro-lifers don't oppose contraception as intrinsically wrong. In the first case, they have to weigh the bad consequences they expect from an economic policy they disagree with against the bad consequences they should expect if something isn't done to change the unwanted pregnancy rate. A lot more factors come into play here, such as which methods will be most effective at reducing unwanted pregnancies, which methods will have better consequences in other respects, how much energy the person is already putting into attempts that they don't see as having bad consequences, and how effective restrictive laws will be as compared with simply changing people's circumstances.
What about the contraceptive issue with those who don't see contraception as intrinsically wrong? A lot of pro-lifers who don't have a problem with contraception in principle will still be extremely hesitant about efforts to promote it among teenagers (or among the unmarried in general, depending on their views about sexual morality). One reason for this hesitation, I think, is that they see such promotion as endorsement of teenage sex (or unmarried sex), and they would see that as participating in something they shouldn't. Or it might be thought of in terms of promotion of something one wants not to promote. Then the wrongness of promoting something wrong or participating in something wrong might be decisive for someone, and we don't have an inconsistent position after all.
Then there might also be bad consequences to consider. I've seen claims that promoting contraception doesn't decrease unwanted pregnancies but actually decreases them. I've never looked at the details of studies on the subject, but I think the explanation for why this might be is that people who most (but not all) of the time use contraception are more likely to feel safer in avoiding contraception than without contraception-promotion, in which case they might have been more willing to abstain from sex than to engage in contracepted-sex most (but not all) of the time. Now it doesn't actually matter to my argument whether these claims are true. Perhaps this effect isn't very strong, and the effect of promoting contraception in preventing pregnancies is much stronger. What matters is that some people believe this claim to be true, and it's not totally unreasonable, even if a closer look at facts might disabuse someone of it (if in fact it's wrong, which I'm not taking a stand on one way or the other). That means they have a consistent position of why they think the effects of contraception-promotion do not actually decrease unwanted pregnancies, and thus they can consistently hold to pro-life principles and want to reduce unwanted pregnancies without wanting to promote contraception.
I recently listened to a Bloggingheads TV diavlog between Sarah Posner and Michael Dougherty, and along the way one of them (I believe Dougherty) mentioned an argument that I don't think I've ever heard before. Apparently some people have argued against promoting contraceptives because they think such efforts will lead to a bad consequence, not just in other areas, but one that has a direct impact on abortion. It may well be, as far as this argument goes, that promoting contraception will decrease the number of unexpected pregnancies, i.e. the number of pregnancies that were not wanted before they occurred. But emphasizing contraception might at the same time reinforce the sense that pregnancy is a bad thing worth avoiding. Of those unexpected pregnancies, such an increased sense of pregnancy as bad might increase the number of unexpected pregnancies been seen as unwanted. That might then increase the number of abortions resulting from unexpected pregnancies, even if the number of unexpected pregnancies goes down because of the contraception. You'd then have to see if it's possible to figure out which effect would be more significant, and my suspicion is that such a task would be very difficult, if not impossible, which might lead one toward caution about a policy that might have a good effect but might also have a bad effect. That would then contribute toward explaining the hesitation from some pro-lifers with respect to policies that promote contraception.
There are plenty of other things that might come to play here, but this should give enough sense that it doesn't automatically follow from pro-life convictions that one ought to favor policies promoting contraception or supporting economic policies that might have the effect of helping more women at risk for unwanted pregnancies to have more economically-viable situations where they'd be less tempted to have an abortion. Perhaps when all is said and done, the best pro-life policy is to oppose abortion and favor restricting it while also promoting contraception. Provided you don't think contraception is intrinsically immoral, that's going to depend on a number of other factors, including some empirical data that I'm not sure is readily available in an indisputable form. But it's not an automatic implication of pro-life principles, and how people settle those other issues will affect what they might consistently say about efforts to promote contraception. Similarly, it's certainly possible that pro-lifers ought to support some given effort to increase the quality of life of those who might be at risk for having an abortion. But whether they should consistently do so will depend quite a bit both on their other views and on empirical data that isn't easily available to most people and may, frankly, not even exist in any understandable form.