What are the causes of IUGR ?
There are many causes of IUGR and many cases are unexplained. The following is only a guide as to some of the causes : • History of restricted foetal growth, hypertension, diabetes, raised alpha fetoprotein or hCG, chronic illness, low weight before pregnancy, poor maternal weight gain (<10kg by 40 weeks), twins, use of alcohol, tobacco or illicit drugs, maternal anaemia, vaginal bleeding, living above 3000 metres, severe lung disease. • Infections syphilis, CMV, toxoplasmosis, rubella, HBV, HSV, HIV • Congenital disorders e.g. trisomy 21, 18, 13, Turners syndrome • Placental pathology e.g. previa abruption • Drugs warfarin, phenytoin, steroids • Maternal smoking causes 30-40% of cases of IUGR (11 cigarettes/day equates to babies weighing 330g less and being 1.2cm shorter on average than non smokers). IUGR occurs in 15-20% of cases of twins.
