Systemic Conditions in Pregnancy

Gestational Thrombocytopaenia

A condition which causes transiently low platelet levels in pregnancy, not associated with maternal/fetus risks.

– It occurs due to plasma dilution as well as decreased production of platelets during pregnancy.

– The problem is that it is similar to immune thrombocytopenia (ITP) which can lead to several problems

– Therefore, one must rule out ITP as it can affect both the mother and fetus (as antibodies cross the placenta)

Symptoms

– This is usually asymptomatic

– Gives isolated decrease in platelet levels which return to normal levels after pregnancy

– Woman has no medical history of thrombocytopaenia outside pregnancy

However, ITP on the other hand does give symptoms which can lead to severe bleeding

–  Purpura and petechiae, especially on the extremities and Bleeding (Epistaxis and menorrhagia)

Diagnosis:

– It is a diagnosis of exclusion. Must first exclude ITP, pre-eclampsia, HELLP syndrome

– If low platelets during booking visit and history of ITP –> test for serum antiplatelet antibodies

Management:

– If confirmed gestational thrombocytopenia –> monitor platelet levels through repeated FBC

– If platelet levels fall very low –> Assume diagnosis of ITP and give steroids (as autoimmune condition) 

Anaemia in Pregnancy

During pregnancy, both the plasma volume and red cell mass increase. However, the plasma volume increases disproportionately, result in a haemodilution effect.

– This predisposes pregnant women to developing anaemia which can lead to several symptoms

– Pregnant women are screened for anaemia at their booking visit  and at 28 weeks

– Long standing anaemia however can result in poor placental perfusion and growth restriction of the fetus

Symptoms:

– Can be asymptomatic

– Dizziness, fatigue and breathlessness

– Mucosal pallor

– Koilonychia

– Angular Stomatitis

Diagnosis:

–  This is confirmed using a FBC which shows a micro or normocytic anaemia

– Cut off levels: 1st trimester < 110g/L               

– At 28 weeks: <105 g/L

Management:

– 1st line is oral iron supplements

– If poor compliance/malabsorption –> give parenteral iron infusion 

DVT in Pregnancy

Pregnancy is a major risk factor for venous thromboembolism, increasing risk by 4-5x

– This is because there is increased levels of fibrinogen and clotting factors VII, VIII, X

– These changes become more pronounced as the pregnancy progresses and so highest risk is post-partum

Risk factors:

– Pre-existing –> Thrombophilia, Cancer, Varicose veins, Smoking, BMI >30, age >35

– Obstetric –> Multiparty >3, C-section, Prolonged labour, stillbirth, PPH

– Transient –> Surgery, dehydration (hyperemesis), Infection, OHSS

Symptoms:

– Unilateral leg pain and swelling (left leg more common in pregnancy)

Diagnosis:

– This is confirmed with compression duplex ultrasound

Management:

– Women are assessed at their booking scan for risk factors for DVT.

– If 3 risk factors –> start LMWH from 28 weeks until 6 weeks postnatal

– If 4 or more risk factors or previous VTE history –> immediate LMWH till 6 weeks postnatal

– If confirmed DVT –> LMWH immediately till 3 months post-partum

Rhesus Disease

This is a condition that results from anti-rhesus D antibodies attacking fetal red blood cells

– The D antigen is the most important antigen of the Rhesus system which is on RBCs.

– Most mothers are rhesus +ve and so will produce anti-D antibodies. But around 1 in 6 mothers are rhesus negative.

If a Rh -ve mother has a Rh +ve fetus, then some foetal RBCs may enter the maternal circulation

– This causes the mother to produce anti-D IgG antibodies which can cross the placenta in future pregnancies

– If the fetus is Rh +ve, this will result in a haemolytic anaemia in the next fetus

Symptoms:

These are seen in a new-born fetus shortly after birth

– Features of anaemia –> fatigue, lethargy, breathlessness

– Features of haemolysis –> jaundice, hepatosplenomegaly

– Oedema –> as the liver is devoted to RBC production, albumin levels fall

– Can lead to heart failure and kernicterus

Diagnosis:

– All babies born to a RhD -ve mother should have cord bloods taken at delivery for:

– FBC (tests for anaemia)                                  

– LFTs –> measures bilirubin levels

– Direct Coombs tests –> will demonstrate antibodies on RBCs of baby

Management:

– Blood Transfusions and phototherapy (makes bilirubin less fat soluble to stop it crossing BBB)

N.B. To avoid complications, the goal is to prevent the disease by giving mother anti-D immunoglobin

– Anti-D immunoglobulin binds to any RhD +ve cells that may have leaked into the maternal circulation

– It prevents the mother from mounting an immune response against these cells and generating anti-D IgG

Prevention:

All mothers are tested for their Rhesus D status at booking

– If positive –> no further action is needed              

– If negative –> give prophylactic anti-D at 28 and 34 weeks

A sensitising event is an event where the mother’s and fetus’ blood may mix during pregnancy.

– In RhD negative mothers, anti-D should be given ASAP after any sensitising event such as:

– Ectopic pregnancy

– Miscarriage >12 weeks

– Abdominal trauma

– Invasive obstetric testing

– Delivery of a rhesus +ve infant (test baby’s blood after birth if mother is RhD -ve)

There are 2 main blood tests that should be considered following a sensitising event:

i) Maternal blood group and Ab screen:

– Determines mother’s ABO and RhD status

ii) Feto-maternal haemorrhage test (FSH):

– This is known as the Kleihauer test

– It is used to assess how much foetal blood has entered the maternal circulation

– Used to determine how much anti-D will be needed for the mother

Intrahepatic Cholestasis of Pregnancy (ICP)

This is a condition which causes cholestasis (stoppage of normal bile flow) in pregnancy

– It commonly occurs during the 3rd trimester when hormone levels are at their highest

– Associated with raised hormone levels (oestrogen and progesterone) and genetic factors

Symptoms:

– Classically gives pruritis in the absence of rash (typically worse on the palms and soles)

– Itching that is worse at night with fatigue and nausea

– Jaundice (<10% of women), dark urine and pale stools

– Increased risk of gallstones

– Fetus –> Increased risk of stillbirth, premature birth and meconium passage

Diagnosis:

– LFTs show raised ALT and bilirubin

Management:

– Monitor LFTs weekly until delivery

– Topical emollients and Ursodeoxycholic acid (relieves itch and liver function)

– Offer induction of labour at 37 weeks  

– This is followed by immediate C-section delivery

Acute fatty liver of pregnancy

This is a serious condition which occurs late in pregnancy. Unlike ICP, it can be fatal for the woman

It is thought to be caused by a disordered metabolism of fatty acids by mitochondria in the mother leading to an accumulation of fatty acids. This overwhelms the beta-oxidation enzymes of the mother and can lead to death.

Symptoms:

– Abdominal pain

– Jaundice, Hypoglycaemia

– Nausea/vomiting (can lead to pre-eclampsia)

Diagnosis:

LFTs show very high ALT –> if unclear, can do liver biopsy for definitive diagnosis

Management:

– Supportive care with IV fluids and glucose to stabalise mother

– This is followed by immediate C-section delivery