Hemolytic Disease of the Newborn

Qun Lu, M.D.

Assistant Professor

Dept. of Pathology and Laboratory Medicine

David Geffen School of Medicine at UCLA

Los Angeles, CA

Clinical History

06/25/05: 36 y o, gravita 3, para 0, 10 1/7

weeks pregnant AA female, came to ER due

to left-sided abdominal pain

PMH:

– lost two pregnancies in first trimesters, no

RhoGam administration, her blood type is B

negative,

– last pap was 3 y ago and normal

– Hypothyroidism diagnosed at age of 8, not

compliant with med

PE

General: BP 110/50, HR 112. T and R normal, a

well- developed, well-nourished, in mild distress.

LUNGS /HEART: WNL

ABDOMEN: Some guarding, but bowel sounds

and had bilateral fullness in both quadrants.

PELVIC: normal external female genitalia, scant

discharge was noted from the cervix. The GC and

Chlamydia cultures were obtained. No blood was

noted. Pelvic bimanual examination revealed

masses up to the umbilicus.

ER work-up

Lab: WBC of 16, HB 3.9, HCT 12.8, PLT

287,000, MCV 64.7, BMP- normal, UA - 1+

Hb and 1+ leukocyte esterase, beta HCG -

291,000.

Pelvic US: IUP at 10-1/7th weeks and also

complex bilateral adnexal masses with

cysts. Each was approximately 10 x 14 x 7

and 10 x 12 x 8 centimeters.

ER Treatment

Admission

IV fluids

Evaluation of her anemia

Transfusion with 2 units of blood

Evaluation of bilateral adnexal masses: CA-

125. Consider further imaging.

Issues

Blood Bank issues: B negative, anti-D (1:256)

and anti-C(1:1) present, concerned with HDN,

currently 10+ weeks pregnancy, not a

candidate for RhoGam

Anemia: iron deficient, started on iron

supplement, no source of bleeding found,

smear – 2+ spherocytes, 3+ microcytes, 2+

fragmented cells, HB studies – 98% Hb A, 1.2%

Hb A2, 0.5%Hb F, no Hb S, C

Issues Adneal masses: CT - no lymphadenopathy, no

metastasis, cystic mass with no papillary

projections or solid part, c/w overstimulation

syndrome. TSH high (41.7), T4 <1mcg/dl, T3 23

ng/dl, both low

Cardiovascular. a right sided DVT, starting

heparin, possibly secondary to venous stasis

from her adnexal masses. Base PTT 25, PT

11.6, INR 1.1, lupus anticoagulant +, further

rheumatology studies ordered

Hemolytic Disease of Newborn

Definition: a hemolytic disease in the newborn

caused by blood-type incompatibility between

mother and child

Maternal Ig G antibodies can cross the placenta

and coating fetal RBCs – hemolysis

Maternal sensitization: history of transfusion or

pregnancy

Common RBC antigens causing

HDN

--Rh antigens. Most common is D antigen, next is c

antigen. IgG can cross placenta.

– ABO antigens: only in infants born to group O

mothers because some have IgG anti-A, anti-B,

anti-A,B antibodies without sensitization, usually

mild HDN

– Kell: Kell antigens are expressed in early fetal

RBCs and bone marrow hematopoietic cells –

cause hemolysis and bone marrow suppression –

severe and early HDN

– Kidd, MNSs, Duffy antigens: rare, but increasing

Prevention of HDN

Nearly all women with Rh negative or weak D

type are identified in early pregnancy by blood

testing.

If mother is Rh-, anti-D is negative,usually given

Rh immunoglobulin (RhIg), also known as

RhoGAM

– 1 vial (300 mcg), around the 28th week of

pregnancy

– at time when vaginal bleeding occurs (calculate)

– at the time of delivery within 72 hours

Maternal-Fetal Bleeding Screening

After vaginal bleeding or delivery, if

screening is negative, just give 1 vial (300

mcg) RhIG. If +, give minimal 2 vials and

add more vials after calculation

Calculating Dosage of RhoGam

First perform the Kleihauer-

Betke test to get the

percentage of fetal red

cells in the mother

Mechanism

Blood smear stained with

acid elution

Hb F is more acid resistant

Fetal RBC darkly stained,

Maternal RBC "ghosts"

Fetal Blood

Maternal Blood

Calculating Dosage of RhoGam

Hemoglobin electrophoresis on

cellulose acetate Hemoglobin HPLC

Calculating Dosage of RhoGam

Method 1:

% of fetal RBC X 50 / 30

Method 2:

If the decimal <0.5,

round up; if the decimal

is >0.5, round up and

then round up again

First Sensitized Pregnancy

Father RBC phenotyping:

– negative for the offending antigen then no further

testing is necessary

– positive for the antigen, serial antibody titer

monitoring is required

Anti-K: HDN tends to happen early and severe

– Frequency of monitoring: every 4 weeks to 28

weeks, then every 2 weeks until birth

– Critical titer: 1:8 or above

First Sensitized Pregnancy

Non anti-K antibodies– Frequency of monitoring: first at 12 weeks gestation,

then at 28, 32 weeks gestation

– Critical titer : the IAT titer is > 1:32 or albumin titer > 1:16 (it varies from hospital to hospital)

– IAT titers of < 1:32 or less are managed non-invasively with repeat antibody titers every 2-4 weeks.

– IAT > 32: Doppler Ultrasound to measure peak systolic velocity of middle cerebral artery or amniocentesis or umbilical blood sampling q 2 to 3 weeks to detect fetal anemia . (N Engl J Med. 2000 Jan 6;342(1):9-14 )

Open circles indicate fetuses with either no anemia or mild anemia ( 0.65 multiples of

the median hemoglobin concentration). Triangles indicate fetuses with moderate or

severe anemia (<0.65 multiples of the median hemoglobin concentration). The solid

circles indicate the fetuses with hydrops. The solid curve indicates the median peak

systolic velocity in the middle cerebral artery, and the dotted curve indicates 1.5

multiples of the median.

Amniocentesis

Bilirubin level: measured by spectrophotometrically measuring absorbance at the 450-nm wavelength in a specimen of amniotic fluid that has been shielded from light ---- Liley curve

Fetal genotyping– For RhE, Rhe, RhC, Rhc, Kell ,and Cellano (k) the

parents' DNA should be tested concurrently

Cytogenetic testing to screen for congenital disease

The Liley Curve

Amniotic fluid bilirubin level (log), vs weeks of pregancy

Zone 1: low risk

Zone 2: intermediate

risk

Zone 3: high risk

Umbilical Cord Blood Sampling

Direct measurement of fetal blood bilirubin

and hemoglobin level

Fetal RBC phenotyping

Technique can be used for fetal blood

transfusion or exchange

More complications

Hemoglobin Concentrations in 265 Normal Fetuses and 111 Fetuses That

Underwent Cordocentesis

Previously Affected Pregnancy

For patients with a previously affected

pregnancy, the timing of the initial procedure

(serial amniocentesis) is determined by past

clinical history. It is usually performed at

least 4-8 weeks earlier than the prior

gestational age at which significant

morbidity occurred.

In women with extremely high titers ( > 256), at

less than 28 weeks, where the fetus does not

demonstrate hydrops, and there is a documented

history of fetal death due to hydrops ---- IVIG

might be offered. The dose is 400 mg/kg per day

for 5 days, with repeat infusions every 15 to 21

days. Specific contraindications to intravenous

immunoglobulin use include a previous episode of

IVIG-induced anaphylaxis (rare) and selective IgA

deficiency.

Symptoms of HDN During pregnancy:

Mild anemia, hyperbilirubinemia, and jaundice

Severe anemia with enlargement of the liver and spleen

Hydrops fetalis - The heart begins to fail due to severe anemia and large amounts of fluid build up in the tissues and organs, at great risk of being stillborn.

After birth:

Severe hyperbilirubinemia and jaundice

Kernicterus - the most severe form of hyperbilirubinemia and results from the buildup of bilirubin in the brain. This can cause seizures, brain damage, deafness and death.

Diagnosis

Mother’s blood: RBC antibodies

Doppler Ultrasound - to detect organ enlargement or fluid buildup in the fetus.

Amniocentesis - to measure the amount of bilirubin in the amniotic fluid.

Fetal umbilical cord blood: antibodies, bilirubin, and anemia

Newborn: umbilical cord blood for blood group, red blood cell count and antibodies, newborn peripheral blood testing for bilirubin levels.

Treatment

During pregnancy:

– Intrauterine blood transfusion of red blood cells, into the

abdominal cavity of the fetus or directly into the umbilical

cord vein

– Early delivery if the fetus develops complications -prevent

worsening of HDN.

After birth:

– Blood transfusions (for severe anemia).

– Phototherapy

– Intravenous fluids (for low blood pressure).

– Help for respiratory distress using oxygen or a mechanical

ventilation

– Exchange transfusion