Complications in Pregnancy Flashcards
Rhesus Isoimmunisation
=Immune Hydrops; Maternal Transplacental Antibody response mounted against Foetal RBC antigens; Ensuing Anaemia leads to Hydrops
Pathophysiology of Rhesus Isoimmunisation
Five Rhesus antigens (C/c, E/e, D); Significant antigens – D, c, E, and atypical Kell
• Foetal cells cross into Maternal circulation in normal pregnancy; Amount increased during sensitising events (E.g. TOP, ERPC, Ectopic, PV bleeding, Blunt trauma, Invasive Uterine
procedures, Intrauterine Death and Delivery)
• Rh D positive foetus vs. Rh D negative mother; Initially, IgM produced
• Re-exposure in subsequent pregnancy causes primed memory B-cells to produce IgG; IgG binds Foetal RBC, which is destroyed in RES leading to Haemolytic Anaemia
o If unable to compensate, severe anaemia leads to HOCF, Foetal Hydrops and Death
o Milder cases – Neonatal Anaemia or Jaundice from increased RBC breakdown
Anti D Prophylaxis
Given to Rh D negative women; Anti-D Immunoglobin binds to Foetal RBC; Prevents maternal
immune system from recognising and becoming sensitised
o RAADP at 28 weeks; Also given within 72h of potentially sensitising event, and after delivery if Neonate is found to be Rh positive
During sensitising events, large Foeto-maternal Haemorrhages might occur; Kleihauer test (HbF in maternal blood) to determine dose of ADP required
o Kleihauer test routine at delivery if Neonate is Rh D positive
Foetal Hydrops
Due to imbalance of Interstitial fluid production and Lymphatic return; Can result from Congestive Heart Failure, Obstructed Lymphatic Flow, or Decreased Plasma Osmotic Pressure
How is foetal hydrops diagnosed?
Diagnosis made by Ultrasound; Might be associated with other structural abnormalities
o Foetal Echocardiography for Cardiac Lesions; Foetal Anaemia measured by Peak
Systolic Velocity MCA flow
o Foetal Blood sampling if Anaemia suspected; In-utero Transfusion in same setting
o Amniotic Fluid, Foetal Blood Karyotyping and Virology
o Maternal Blood testing – Kleihauer (Foeto-maternal Haemorrhage), Antibody
Screening (Immune Hydrops), Virology, Hb Electrophoresis (α-Thalassemia)
Causes of non immune hydrops
Congenital Parvovirus, α-Thalassemia Major,
Massive Foeto-Maternal Haemorrhage, G6PD deficiency, Cardiac Structural and Conductive
Abnormalities, Aneuploidy, Infection (Toxo, Rubella, CMV, VZV), Twin-twin transfusion
What to do in severe polyhydramnios
Amnioreduction may reduce risk of prem; Consider steroids as reduction carries small risk of causing prem
Oligohydramnios
Normal volume depends on Urine production (after 20/40), Foetal Swallowing and Absorption; Measurement by Ultrasound
Causes of Oligohydramnios
SROM, IUGR, Foetal Renal abnormalities, Post-dates, Foetal Urinary obstruction
Complications of Oligohydramnios
Complications can be related to cause (PROM, IUGR) or reduced volume (Lung Hypoplasia if <22/40, Limb Abnormalities if prolonged)
o Should investigate for rupture of membranes; If suspected, FBC, CRP and Swabs taken
o If SROM 34 – 36/40; Induce Labour; CS if other indication
o If before 34/40 – Prophylactic Oral Erythromycin, monitor for signs of infection, Daily
CTG and consider Induction at 34 – 36/40
Causes of polyhydramnios
Maternal DM, Twin-twin Transfusion, Foetal Hydrops, Foetal GI obstruction,
Neurological or Muscular Abnormalities (failure to swallow), Idiopathic (usually mild)
Complications of polyhydramnios
Preterm (due to Uterine stretch), Malpresentation, Maternal discomfort
• Important to exclude maternal diabetes with GTT
What determines growth potential?
Attaining growth potential depends on Maternal, Placental and Foetal factors;
Growth potential is determined by Maternal height (Paternal height to lesser extent), Maternal weight in early pregnancy, Parity, Ethnicity and Foetal Sex)
What is IUGR
Implies that foetus is pathologically small (=Small for Gestational Age)
o Most commonly set that estimated weight is below tenth percentile
Associations with IUGR
IUGR associated with 6 – 10-fold Perinatal Mortality, four-fold increase in Cerebral Palsy; Foetal Distress, Asphyxia, Meconium Aspiration, NEC, Hypoglycaemia and Hypocalcaemia
Symmetric IUGR
seen in very early onset IUGR, and with Chromosomal Abnormalities
Asymmetric IUGR
(Head-sparing) – Undernourishment and Placental Insufficiency most commonly
Maternal factors causing IUGR
Chronic Maternal Disease (HTN, CVS, CKD), Substance Abuse, Smoking, Autoimmune Disease (Increasing APLS), Poor Nutrition and Socioeconomic Factors
Placental Insufficiency causing IUGR
Abnormal Trophoblast Invasion (Pre-Eclampsia and Accreta), Infarction, Abruption, Praevia, Chorioangiomas, Abnormal Cord/Insertion
Foetal factors causing IUGR
Genetics (Aneuploidy), Congenital Abnormalities (Cardiac, Gastroschisis), Congenital Infections (CMV, Rubella, Toxo), Multiple Pregnancies
Management of IUGR
- Early Identification, Foetal Monitoring; Continue Pregnancy as long as safely possible and delivery before excessive compromise
- 1/3 do not reach predicted adult height; Might have neurological deficits
Effects of poor glycaemic control
leads to increased
Foetal and Neonatal Morbidity and Mortality
How many pregnancies does diabetes affect?
Established Diabetes affects 1 – 2% of pregnancies;
Which pregnancy hormones are diabetogenic?
Many pregnancy hormones (HPL, Cortisol, Glucagon, Oestrogen and Progesterone) are
Diabetogenic; Insulin requirements also increased throughout and peak at term
Effects of hyperglycaemia
leads to Foetal Hyperglycaemia and Hyperinsulinism
o Leads to Foetal Macrosomia, Organomegaly, Erythropoiesis and Polyuria which can lead to Polyhydramnios
o At delivery, Neonatal Hypoglycaemia might occur with removal of Maternal glucose supply in the Hyperinsulinaemic Foetus
o Also, Reduced Production of Pulmonary Phospholipids – Increased risk of RDS