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Obstetrics Simplified - Diaa M. EI-Mowafi

Congenital Anomalies

Incidence

2-3 % of all newborns.

Aetiology

  • Hereditary and genetic.
  • Ionising irradiation:
    • < 5-10 rads: no adverse effects.
    • 10-25 rads: possible adverse effects.
    • > 25 rads: documented adverse effects as foetal death, multiple malformations, intrauterine growth retardation, or leukaemia.
  • Infections: e.g.
    • Rubella.                   
    • Cytomegalovirus       
    • Herpes simplex virus.
    • Chickenpox virus.       
    • Mumps.                
    • Smallpox virus.
    • Poliovirus.
    • Toxoplasmosis.       
    • Syphilis.
  • Maternal diseases: e.g.
    • Diabetes mellitus.     
    • Maternal anoxia.        
    • Phenylketonuria.
  • Drugs: The most well documented are:
Drug Effect
I- Antibiotics
Streptomycin Nerve deafness.
Tetracycline Dental discoloration.
Chloramphenicol Gray syndrome.
Sulphonamides Jaundice and kernicterus.
Aminoglucosides (e.g. gentamycin, kanamycin) Nephrotoxic.
II- Hormones  
Diethylstilbestrol Vaginal adenosis and adenocarcinoma.
Androgens Virilization of female foetus.
Contraceptive pills VACTREL syndrome = Vertebral, Anorectal , Cardiac, Tracheal, Renal, Oesophageal and Limb abnormalities.
Corticosteroids Rarely, cleft palate.
III-Oral anticoagulant  
Coumarins (e.g. Warfarin) Chondrodysplasia punctata (saddle nose, frontal posing, mental retardation, cataract) and foetal haemorrhage.
IV- Cytotoxic drugs Abortion and multiple anomalies.
V- Antithyroid Goitre and mental retardation.
VII- Salicylate Foetal haemorrhages.
VIII- Antihistaminics, antiepileptics, oral hypoglycaemics may be teratogenic.

Common Congenital Anomalies

  • Chromosomal abnormalities
    • Trisomy 21 (Down’s syndrome).   
    • Trisomy 13,15.
    • Trisomy 18.
    • Turner's syndrome(45 XO).
    • Klinefelter syndrome (47 XXY).
  • Central nervous system: e.g.
    • Anencephaly (absent vault of the skull).
    • Enencephaly (hyperextended head with fusion of the tissues over the occiput and sacrum).
    • Hydrocephalus.
    • Spina bifida.
    • Meningocele.
    • Encephalocele.
    • Mental retardation.
  • Gastrointestinal system:
    • Hare lip and cleft palate.    
    • Oesophageal atresia.
    • Tracheo-oesophageal fistula.   
    • Anal atresia.            
    • Diaphragmatic hernia.
    • Exomphalos (protrusion of abdominal contents through the umbilical ring covered with transparent sac).
    • Gastroschisis (protrusion of the bowel through an abdominal wall defect but the umbilical cord is not involved)
  • Genito-urinary anomalies:
    • Renal agenesis.
    • Horse shoe kidney.   
    • Ectopia vesica.  
    • Hydronephrosis.
    • Hypospadias.
    • Undescended testis. 
    • Ambiguous genitalia.
  • Cardiovascular:
    • Patent ductus arteriosus.
    • Valvular affection.
    • Coarctation of the aorta.
    • Septal defects.
  • Limbs anomalies.
  • Eyes or ears anomalies.

Diagnosis

  • Antenatal alerting signs:
    • Family history.
    • Positive consanguinity.  
    • Old mothers (>40 years).
    • Oligohydramnios and polyhydramnios.
    • Malpresentations or malpositions as it may be the result of congenital anomalies as hydrocephalus, anencephaly or goitre.
    • Intrauterine growth retardation which may be associated with microcephalic dwarfism or teratogenic infections as rubella, toxoplasmosis and chickenpox.
    • Abnormal antenatal cardiotocography may be the sign of congenital heart disease.
  • Investigations: (see foetal wellbeing).
    • Chorionic villus biopsy.  
    • Amniocentesis. 
    • Cordocentesis.
    • Ultrasound.
    • Magnetic Resonance imaging (MRI).
    • Fetoscopy.
    • Maternal serum alpha fetoprotein.

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