How can you not know you are pregnant?

This would be the TV show "I didn't know that i was Pregnant" that is on TLC, not unfortunately a miraculous revelation about myself.  Today's show is a 57 year old woman who undergoes IVF with a donor egg.  I'm intrigued to see how this is going to be a surprise pregnancy for this particular woman.  I mean honestly, if you pay someone to put fertilized eggs into your uterus then how on earth  is it supposed to be a surprise? 

I am home sick today.  I left work at noon with a horrible migraine and am still feeling the effects.  I spent most of the afternoon yesterday completely unconscious because the light was too much for me to bear. 

I have always been the victim of migraines, but ibuprofen always used to save me... now i no longer take ibuprofen on the off chance that I get pregnant, or because it might interfere with ovulation or any of the other things that we've heard.  I mean if ibuprofen was really working as a birth control method then I am sure lots of teen girls would be popping that when they couldn't get the real pill.  But, when you are trying to have a baby then apparently you will listen to just about any rumor that can have an impact on your ability to have a child... at least i will.

Back to the 57 year old she started to hemorrhage and was diagnosed with a miscarriage... and apparently no one bothered to check via ultrasound or pregnancy test??  Honestly... and she hemorrhages for months and no one looks to see if she's had any retained tissue?  Who are these doctors?

This show both intrigues and depresses me.  As a woman who is trying to get pregnant the idea that you could be pregnant for months and not notice that it was going on is a strange fantasy... and of course it leads me to play mind games every single month.  Even once my period has started i ask myself... am i actually having my period?  is it breakthrough bleeding?  Is this period lighter than usual?  It is crazy the number of ways i can pretend that even despite all of the evidence to the contrary I will take any possible opportunity to pretend that maybe, just maybe i will one day be a candidate for this show.  That despite the plethora of pregnancy tests within arms reach that i can take at any point in time i might somehow be pregnant without knowing it.