management of an Rh negative women

Briefly explain the pathophysiology of Rh incompatibility

1. An Rh-negative mon + Rh-positive dad conceive a Rh-positive fetus

2. Cells from Rh-positive fetus enter womans’ bloodstream

3. Woman becomes sensitised and forms antibodies to fight Rh-positive blood cells

4. In the next pregnancy Rh-positive pregnancy, maternal antibodies will attack fetal RBC\

At the first ANC booking , the mother’s is tested for Rh and is negative, what is the next step? (4)

Give anti-D then perform indirect Coombs test then retest @ 28 weeks

Give anti-D again at week 32-34

Then anti-D closer to delivery

Then within 72 hours of delivery

The mother has retested at 28 - 40 weeks and is still Rh-, what is the next step?

Give the mother antiD 300 mg at every sensiting event (Ectopic pregnancy / termination of pregnancy)

Before giving the Rh-negative mother anti-D and if titre is >1.8, what should be done?

Refer to MAFU for test for Rh status of fetus > if fetus is Rh-negative there’s no need for anti-D in mother

If the titre <1:8 in the indirect Coombs test what should be done?

Repeat after 4 weekly

If testing was does before 20 weeks and mother is Rh- with Rh+ fetus, what is the dosages of anti-D?

50 mcg anti-D

If testing was does after 20 weeks and mother is Rh- with Rh+ fetus, what is the dosages of anti-D?

100 mcg anti-D

What is the management following anti-D allo-immunisation?

1. Refer patients to correct institution

2. Check maternal anti-D levels regular every 4 weeks

3. Perform fetal middle cerebral artery Doppler scans (fetal anaemia) > if anemia perform intrauterine transfusion via umbilical vein

4. Cordocentsis > estimate fetal hemolysis

What are the investigations for hydrops fetalis? (4)

1. Fetal movement

2. Antenatal fetal heart rate

3. Amniocentesis

4. Doppler (U/S)

What are the investigations for hydrops fetalis? (4)

1. Fetal movement

2. Antenatal fetal heart rate

3. Amniocentesis

4. Doppler (U/S)

What may you find on ultrasound on a baby with hydrops fetalis? if done before / after 24 weeks which method is used?

Cardiomegaly

Before 24 weeks > transperitoneal

After 24 weeks > transvascular

What is the postnatal management of the baby if mother was Rh-negative? (3)

1. Determine Rh of the baby on cord blood

2. If newborn is Rh positive give 100 mcg anti-D to all mothers

3. If you suspect fetomaternal haemorrhage give 300mcg

What type of test do you do to calculate additional antiD if the fetomaternal haemorrhage is greater than 4 ml? What does this test us with ? (3)

Kleihauer Betke test > used during pregnancy to measure fetal blood cells in maternal bloodstream + assess fetomaternal hemorrhage + calculate anti-D doses

The Kleihauer Betke test uses acid elation to reveal maternal and fetal blood, what colour is each?

Maternal RBC > pale

Fetal RBC > pink / bright red