When my daughter was in high school she told me about some girl who was sexually active with her boyfriend and would talk about going a number of times to Planned Parenthood for either Plan B or the morning after pill or something.
I'm not sure what your thoughts are on Plan B - but research has pointed towards it being
less likely to prevent implantation of a fertilized egg than the typical monthly hormonal birth control pill. I only mention this because I think the perception with Plan B among some Christians (including formerly, myself) is that it's primary mode of action is to prevent implantation, and the research which I've seen indicates that it may not prevent implantation at all:
By 2007, scientific consensus was building that morning-after pills did not block implantation. In one study using fertilized eggs that would have been discarded from fertility clinics, Dr. Gemzell-Danielsson found that adding Plan B in a dish did not prevent them from attaching to cells that line the uterus.
Later, in 2007, 2009 and 2010, researchers in Australia and Chile gave Plan B to women after determining with hormone tests which women had ovulated and which had not.
None who took the drug before ovulation became pregnant, underscoring how Plan B delays ovulation. Women who had ovulated became pregnant at the same rate as if they had taken no drug at all. In those cases, there were no difficulties with implantation, said one of the researchers, Gabriela Noé, at the Instituto Chileno de Medicina Reproductiva in Santiago. Dr. Blithe of the N.I.H., said, “No one can say that it works to inhibit implantation based on these data.”
Full Article Here (Though it may require special access or creation of an account.)
I'm not an expert on birth control - so take this with a grain of salt - but in contrast, the monthly birth control pill is believed to have several modes of action, with (among other things) two of them being: 1. Preventing ovulation, and 2. Preventing implantation by thinning the uterine wall / endometrium. The changes to the endometrium which are required for the second mode of action to work are thought to take several months to develop. Since the morning after / Plan B pill is not something that is taken regularly, there is not enough time for it to change the uterine wall in the same manner as monthly birth control.
I say all this as someone who, when it first came out, found the widespread use of Plan B birth control to be distasteful - because it seemed like preventing implantation was it's main mode of action. But the research seems to indicate that is definitely not the case.
Edit: To be clear - I don't think it is known if (or at what rate) monthly hormonal birth control acts to prevent implantation either. I think preventing ovulation is established as it's main mode of action, and that preventing implantation is stated as being possible, but likely rare. But as I said - take all that with a grain of salt. This is a subject which it was difficult to find clear answers and solid numbers for, when I went to do the research years ago.
My personal beliefs are that I avoid any form of birth control which has the possibility of affecting life after conception. This includes hormonal birth control - because while it is normally stated (per previous research) that prevention of implantation is unconfirmed and/or a rare possibility - it seems like the possibility is still there. I encourage all Christians (and non-Christians, for that matter) to do research on the various forms of birth control, how they work, and to wrestle that out with your conscience before God. I am not a person who believes that birth control should be outlawed - these are just my personal religious and spiritual beliefs. I do think it is an important spiritual subject for Christians to take into consideration. I personally don't know that such forms of birth control should be forbidden by church doctrine, either - but I can respect that there are some denominations who choose to go that route.
