- A 29-year-old woman presents at 28 weeks gestation for a scheduled check-up. She states that her baby is moving as much as usual and she is feeling well. On physical exam you see a gravid uterus that extends 28 cm above the pubic symphysis. Of note this is this mother's first pregnancy. Her vitals are within normal limits, she is currently taking a multivitamin and folate and her blood type is A negative.
- Caused when a Rh negative mother carries a Rh positive fetus
- Mother generates anti-Rh antibodies (IgG) during exposure to an Rh positive baby at
- ectopic pregnancy
- During her second pregnancy antibodies cross the placenta and cause hemolysis in the fetus
- fetal disease depends on how much IgG crosses placenta and ability of fetus to replenish RBC
- causes fetal anemia leading to
- ascites and edema
- high output cardiac failure
- worst case scenario is hydrops fetalis
- Rh is a surface protein on RBC that is carried in an autosomal dominant fashion
- if the mother is Rh negative, but the father is Rh positive, there is a 50% chance that the baby will be Rh positive
- Identify at-risk pregnancies
- mother is Rh negative and father is either positive or unknown
- Identify fetal anemia
- analyze amniotic fluid for evidence of hemolysis via bilirubin levels
- meased as optical density (ΔOD450)
- perform percutaneous umbilical cord sampling
- Administer RhoGAM (Anti-Rh antigen) if mother Rh negative and father Rh positive
- within 72 hours of delivery, risk of subsequent sensitization drops from 15% to 2%
- if given at 28 weeks risk drops to 0.2%
- Other times to administer RhoGAM
- external cephalic version
- ectopic pregnancy
- Kleihauer-Betke test measure fetal RBCs in maternal circulation and determine degree of fetal-maternal bleed and consequent dose of RhoGAM to administer
AVERAGE 4.0 of 1 RATINGS
Qbank (0 Questions)
Level of Evidence 5 and Other Journal Articles (includes Case Reports, Expert Opinions,
Personal Observations, and Biomechanic Studies)
Zolotor AJ, Carlough MC. Update on prenatal care. Am Fam Physician. 2014 Feb 1;89(3):199-208.
PMID:24506122 (Link to Abstract)
Fung Kee Fung K, Eason E, Crane J, Armson A, De La Ronde S, Farine D, Keenan-Lindsay L, Leduc L, Reid GJ, Aerde JV, Wilson RD, Davies G, Désilets VA, Summers A, Wyatt P, Young DC; Maternal-Fetal Medicine Committee, Genetics Committee. Prevention of Rh alloimmunization. J Obstet Gynaecol Can. 2003 Sep;25(9):765-73.
PMID:12970812 (Link to Abstract)
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- Brochert's Crush Step 2. O'Connell, Theodore. Philadelphia: Elsevier Saunders, 2013.
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