When Prenatal Patients Receive WinRho (Rho(D) Immune Globulin)

All Rh-negative pregnant women should receive WinRho at 28 weeks gestation and within 72 hours after delivery of an Rh-positive infant. 1, 2

Standard Prophylaxis Protocol

Administer 300 mcg (1500 IU) at 28 weeks gestation to all unsensitized Rh-negative women when fetal blood type is unknown or known to be Rh-positive 1, 2, 3
This two-dose protocol (antenatal + postpartum) reduces alloimmunization rates from 12-13% down to 0.1-0.2% 1, 2
Alternative dosing: Two doses of 100-120 mcg may be given—one at 28 weeks and one at 34 weeks 4

Administer 300 mcg within 72 hours of delivery if the infant is Rh-positive 1, 2, 3
Although optimal within 72 hours, delayed administration up to 28 days post-delivery still provides benefit and is preferable to no administration 1, 3
If delivery occurs within 3 weeks after the 28-week dose, the postpartum dose may be withheld unless fetomaternal hemorrhage exceeds 15 mL of red blood cells 3

Spontaneous or induced abortion: Administer 50 mcg (minimum 120 mcg if 50 mcg unavailable) within 72 hours 1, 5, 4
Threatened abortion with heavy bleeding or abdominal pain: Administer RhIG, as fetomaternal hemorrhage occurs in 48% of threatened abortions 1
Ectopic pregnancy: Administer minimum 120 mcg 4
Fetal RBCs display D antigen from as early as 6 weeks gestation, making sensitization possible even in very early pregnancy 1, 2

Miscarriage, abortion, or ectopic pregnancy ≥13 weeks: Administer 300 mcg 3, 4
Amniocentesis (15-18 weeks or third trimester): Administer 300 mcg 3, 4
Chorionic villous sampling after 12 weeks: Administer 300 mcg 4
Cordocentesis: Administer 300 mcg 4
Placental or vaginal bleeding at any gestational age: Administer RhIG to prevent alloimmunization 1

Abdominal trauma in second or third trimester: Administer 300 mcg, as 28% of pregnant patients with minor trauma have fetomaternal hemorrhage 1, 3
Placental abruption, external cephalic version, or placenta previa with bleeding: Administer 300 mcg with consideration for quantitative testing for fetomaternal hemorrhage 4
If trauma or procedure occurs at 13-18 weeks and requires RhIG, give another full dose at 26-28 weeks to maintain protection 3

Standard 300 mcg dose covers up to 15 mL of fetal red blood cells (approximately 30 mL whole blood) 3, 4
For hemorrhage >15 mL of fetal RBCs: Perform quantitative testing (modified Kleihauer-Betke) and administer additional 10 mcg for every 0.5 mL of fetal red blood cells beyond the standard dose 3, 4
Calculate total syringes needed by dividing red blood cell volume by 15 mL; round up to next whole number 3

72-hour window is optimal but not absolute—give as soon as recognized up to 28 days after sensitizing event 1, 3
The half-life of IgG is 23-26 days, so passively acquired anti-D levels must be maintained throughout pregnancy 3
A repeat antepartum dose at 40 weeks is generally not required if the 28-week dose was given on schedule 4

Intramuscular injection preferred: Deltoid muscle of upper arm or lateral thigh muscle 3
Avoid gluteal region due to risk of sciatic nerve injury 3
DO NOT inject intravenously or into the neonate 3
Both IM and IV routes are equally effective when appropriate preparations are used 6

Do not withhold based on early gestational age alone—fetal RBCs express D antigen from 6 weeks onward 1, 2
Do not assume minimal bleeding eliminates risk—even small fetomaternal hemorrhage can cause sensitization 1
Do not give to women with "weak D" (Du-positive)—these women should not receive anti-D 4
Verify blood type before withholding—if unknown and testing unavailable, administer RhIG as risks of administration are minimal compared to sensitization consequences 1, 2
Do not forget initial screening—all pregnant women should be typed and screened at first prenatal visit and again at 28 weeks 4