Well I just gotta throw my two cents in, as a Rh- woman with a Rh+ Dh, and a Rh+ dd....
When we were pregnant, we planned on having a homebirth with our direct entry midwife. I was still seeing a Dr though cause I had insurance and I hadn't decided on the Rhogma issue. Basically I saw the Dr too cause the MW had no reliable way of obtaining RhoGam for me if I decided I wanted it. So around the issue, my MW supplied me with lots of info and told me she would support my choice. MY Dr actually told me there were no risks... when I asked for the insert and showed her where it listed risks she blew it off !! I was pissed ! This was something I took very seriously... My own parents had endured the Rh- mama factor too, my big bro was +, they weren't sure if they would have a problem with me, but I turned out to be Rh- like mom. She had lost a baby before me, can't imagine why, but who knows ? (Rh incompatibility ?).
Anyways, My MW gave me some good info, Some was from Midwifery Today, some was from Mango Mama (is that gone now ? It also had info on DU fator, though I could never find any more about it.). I collected as much info as I could, and made my best choice. I calculated a slight statistical difference set as "safer" to get the shot at 28 wks... It was really a gut wrenching decision for me.
Then the birth took many twists and turns, and in hour 26, after 5 hours of pushing (standing, kneeling, all 4's, on toilet, in bed, in bed sitting up, sqatting, leaning, screaming, silent ,shitting, puking... and more...) ...with no progress and merconium leaking, we had to go to the hospital, eventually in surgery.
After dd was born they tested her cord blood (I believe, they didn't take it from her) and found she was Rh+. The tech came by to give me the shot... right after blood for a coombs test... I was like, well can't you test me and THEN tell me if I need the shot ? He said no, this is how they do it, they test you, but give you the shot, before they do the test to see if you need it
And anyways, I knew I had likely been exposed to some blood in the c/sec birth, and that someday I might want another child, so I took the shot. In this case I felt it was warrented, ,what with by surgical exposure to + blood and wish for future child. And I wasn't pregnant anymore, so I wasn't exposing my baby to mercury (except, I was BFing but less risk).
Risk for exposure increases:
~When the cord is cut before it finishes pulsing and/or placenta is delivered
~During a surgical birth
~At any time where the blood could mix such as amniocentesis, villi sampling, surgery including c/sec birth, If the placenta were tol oosen from the wall prematurely (I forget the term just now
Anyways, I wanted to say, find out all you can, talk to everyone, and make your best decision... It was hard for me to get the shot because I didn't want it on just about all levels, but I knew it was best for us. And I wound up with an exposure, so perhaps it has helped preserve my future fertility. It feels in retrospect like intuition took over when I made that decsion I haven't noticed any effects, thank goodness. My Dr was unable/unwilling to help me get the thimerserol free (mercury free) shot. She was such an A$$ about the whole thing.
It's not for everyone, but don't feel bad if you have to get it either. We all do our best.
And those time frames are probably mostly cause that is the times they studied in the studies on Rhogam. For instance, you are supposed to get the post birth shot within 72 hrs.... why ? They don't know if it works after that, but they studied up to 72 hrs and that timeframe works so they are sticking with it.
ABTW, and this will help you feel better if you do/did get the shot, the people who supply the human products for the shot are pretty consistent, they often "donate" (paid ? I dunno...probably) for years on end. My point is, their medical histories are checked and monitored more than, say, whoever walks in off the street into the clinic to donate blood for cash, KWIM ? Anyways it helped me feel better, my general basis being to avoid meddling in the human body in general..., well, I was uneasy to say the least.
Hey thanks if you stuck with me this post was incredibly long !!