Not really; notice that she was still politically active until the onset of labor, yet they have *no* photos of the last month. None of the other photos really show the abdominal region very well, which is common for women who pose for a lot of photos. Show me some tight abs within 60 days of the birth, and I'll believe it.
Also, they point to a crop of
this photo as evidence, but not the full photo, because in this one, not only are both of the older daughters looking a bit chubby, but the wrong one is making the "telltale" cradling gesture that Bristol is doing in the sage colored sweater photo in the article. They even admit the two photos are at least 3mo apart ("late 2007" and "March 9") but Bristol doesn't look like she's gained much in the belly. In fact, despite their "Bristol's chest is sticking out, a normal body reaction when sucking in stomach muscles." comment, her bust looks bigger in the earlier photo; if the breasts shrink at some point during the pregnancy, I'm sure my wife would like to know when. (Besides, show me a teenage girl who *doesn't* try to suck in her gut and push her chest out for photos that she knows a lot of cute guys will see.)
Here's 12-4-06, and Bristol looks a bit chubby...was she showing several months before conception, or does she just need to do a few situps?
Now, from a simple logic standpoint, notice that Sarah's belly is pretty well hidden in the above photos, but Bristol's is right out there in the open. They were clearly taken by pros, and the whole family is obviously accustomed to posing for photos, so if they're trying to hide a pregnancy, don't you think they'd rearrange a bit to get the belly out of sight?
Besides, even if it is true and mom's gone through all this hassle to avoid an abortion due to her beliefs, I just don't see that as being such a bad thing. A bit odd, but it would show strong convictions and a willingness to meet them even through personal sacrifice.
Edit to add:
Look at the lighting
in this one; does the sun even get that high during the Alaskan winter? They're claiming late 2007, but the shadows on the people and the distant background indicate the primary light source is at a pretty high angle. The family is also dressed for fairly warm weather. I'm guessing this was taken long before the pregnancy would have shown at all.