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Michele's Pregnancy Journal

Week 29
~ The Rh Factor

It occurred to me that I never properly explained the shot I received, and why I got it. Let me see if I can briefly explain:

About 85% of the population is Rh positive (this means they carry a specific protein on the surface of their red blood cells), leaving about 15% Rh negative, or lacking this protein. This does not affect the health of the person whatsoever. However, in a case where an Rh negative woman gets pregnant by an Rh positive man, their future babies (not that baby, but the rest of them) are potentially in danger. Obviously, this is a rarer occurrence, seeing as that with 15% of the population being Rh negative and assuming half of those are women, roughly only 7% of all women are Rh negative... and they'd have to become pregnant by an Rh positive man to have the problem.

The problem is this: if the first baby they carry together is also Rh positive like his or her father, then this puts all future Rh positive babies they carry together at risk for a lot of health problems. The mother and her baby's blood usually intermingles during delivery. When this happens, the mother's blood recognizes these proteins as being foreign, and creates Rh antibodies against the Rh proteins. It still doesn't affect that first baby. But in subsequent pregnancies, if the new baby she is carrying has an Rh positive blood type (which can't be determined until after he or she is born), the mother's antibodies again recognize the foreign proteins and this time, they attack. And mom and dad have a 50% chance of conceiving an Rh positive baby with each pregnancy.

The new (Rh positive) baby's blood count can get dangerously low when this happens, since the antibodies cause swelling and rupture of the baby's red blood cells. The newborn can also suffer severe anemia, jaundice, brain damage, and heart failure or death. If the mother already has developed antibodies, blood transfusions can be given to the fetus in utero or after the baby is born. The Rh immune-globulin I received prevents the development of these antibodies like a vaccine would.

Cody's dad was Rh positive, but I got the shot during week 28 of my pregnancy with him; and fortunately after Cody was born it was found that he had an Rh negative blood type like me -- so didn't need a second shot, and the first was precautionary anyway. If his blood type has been Rh positive, I'd have needed a second shot within 72 hours of his birth. My husband is also Rh positive, so we did the precautionary 28-week shot this pregnancy too. We'll see if little Milo spares me that second shot in October -- it's given in the hip and it's not a lot of fun! I'll need the shot with every baby Justin and I conceive from here on out, as well.

Not much else to report -- I got a lot of sleep last night, since there was a massively loud thunderstorm and the pounding rain lulled me back to sleep after every time I got up to pee (and after Cody came in scared of the loud thunder). I'll probably take another nap this morning, too. I've been getting up at 6:15 every morning and we haven't been going to bed until midnight nearly all week... I am exhausted! But at least Cody's back in school and it gives me time to get some things done around the house. Countdown to Milo is 8-10 weeks! I am going to start taking my evening primrose oil in 6 weeks (another educational story for another day).

I also went to my first La Leche League meeting yesterday. It was awesome! I'll probably save that one for next week, as well. One of my neighbors is a leader, and she invited me to a meeting before Milo arrives, which is good. It'll be great to get pre-help with breastfeeding before he gets here. I'm not anticipating any of the same breastfeeding problems I had with Cody, but the monthly meetings are a really great resource. If you have them in your area, you should check them out at and go to a meeting.


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