Obstetric Haematology Flashcards
What are blood count changes in pregnancy?
Thrombocytopenia in pregnancy
What are coagulation changes in pregnancy?
Thromboembolic disease
Complications of pregnancy
DIC syndromes
What is the normal full blood count in pregnancy?
Mild anaemia: Red cell mass rises (120 -130%), plasma volume rises (150%)
Macrocytosis: Normal, folate or B12 deficiency
Neutrophilia
Thrombocytopenia: Increased platelet size
What is the blood iron requirement of pregnancy?
- 300mg for fetus
- 500mg for maternal increased red cell mass
RDA 30mg; Increase in daily iron absorption:1-2mg to 6mg
What is the folate requirement of pregnancy?
Growth and cell division
Approx additional 200mcg/day required
What may iron deficiency in pregnancy cause?
IUGR
Prematurity
Postpartum haemorrhage
What is the importance of folic acid in pregnancy? What is the normal supplementation of folic acid in pregnancy?
Advise reduces risk of neural tube defects
Supplement before conception and for ≥ 12 weeks gestation
Dose 400μg/day
What is the definition of anaemia in the first trimester?
Hb < 110 g/l
What is the definition of anaemia in the second and third trimesters?
Hb < 105 g/l 2nd and 3rd trimester
What is defined as major haemorrhage during labour?
Blood loss 1L
What are causes of thrombocytopaenia in pregnancy?
Physiological: ‘Gestational’/incidental thrombocytopenia
Pre-eclampsia
Immune thrombocytopenia (ITP)
Microangiopathic syndromes
All other causes: Bone marrow failure, leukaemia, hypersplenism, DIC etc.
What is gestational thrombocytopaenia?
Physiological decrease in platelet count ~ 10%
>50x109/l sufficient for delivery (>70 for epidural)
Dilution + increased consumption
Baby not affected
Platelet count rises D2 – 5 post delivery
What is the epidemiology of ITP?
5% of thrombocytopenia in pregnancy
TP may precede pregnancy
Early onset
What are treatment options for ITP?
IV immunoglobulin
Steroids etc.
How are babies affected with maternal ITP?
Unpredictable (platelets <20 in 5%)
Check cord blood and then daily
May fall for 5 days after delivery
Bleeding in 25% of severely affected (IVIG if low)
Usually normal delivery
Which tests are used to identify VTE in pregnancy?
VQ perfusion or Doppler
(NOT D-Dimer)
What are factors which increase risk of VTE in all pregnant women?
Changes in blood coagulation
Reduced venous return: ~85% Left DVT
Vessel wall
What are variable factors which increase risk of VTE in pregnant women?
Hyperemesis/dehydration
Bed rest
Obesity: BMI>29 3x risk of PE
Pre-eclampsia
Operative delivery
Previous thrombosis/thrombophilia
Age
Parity
Multiple pregnancy
Other medical problems: HbSS, nephrotic syndrome, IVF: ovarian hyperstimulation
What is the treatment for VTE in pregnancy?
LMWH as for non-pregnant; does not cross placenta.
RCOG recommend once or twice daily
Do not convert to warfarin (crosses placenta)
After 1st trimester monitor anti-Xa
4 hour post 0.5-1.0u/ml
How long before an epidural should LMWH be stopped?
Wait 24 hours after treatment dose, 12 hours after prophylactic dose
What is chondrodysplasia punctata?
Abnormal cartilage and bone formation
Early fusion of epiphyses
Nasal hypoplasia
Short stature
Asplenia
Deafness
Seizures
Why should warfarin not be given?
Warfarin is teratogenic in the 1st trimester
What is antiphospholipid syndrome?
Recurrent miscarriage + persistent Lupus anticoagulant (LA) and/or antiphospholipid antibodies
What are the three potential presentations of antiphospholipid syndrome?
Adverse pregnancy outcome: Three or more consecutive miscarriages before 10 weeks of gestation.
One or more morphologically normal fetal losses after the 10th week of gestation.
One or more preterm births before the 34th week of gestation owing to placental disease.
What is the potential treatment of antiphospholipid syndrome?
Aspirin and heparin
(Better than aspirin alone)
What are major risk factors of postpartum haemorrhage?
Uterine atony
Trauma
All haematological factors are minor variables for post-partum haemorrhage except:
Dilutional coagulopathy after resuscitation
DIC in abruption, amniotic fluid embolism etc.
What is the relationship between Disseminated Intravascular Coagulation (DIC) and pregnancy?
Coagulation changes in pregnancy predispose to DIC.
What is decomposition for DIC in pregnancy precipitated by?
Amniotic fluid embolism
Abruptio placentae
Retained dead fetus
Preeclampsia (severe)
Sepsis
