If during pregnancy a foetus is thought to be smaller than it should be for the length of the pregnancy, doctors may refer to the problem as intrauterine growth retardation. This may be assessed both clinically and by ultrasound. This failure of foetus to achieve its full growth potential may be due to problems with the foetus, mother or placenta.
Causes of smaller foetus
Factors due to the mother include high blood pressure (maternal hypertension), german measles (rubella), toxoplasmosis, Herpes infection, cytomegalovirus, cytotoxic medications, irradiation, diabetes, chronic renal disease, malnutrition, anaemia, family history, drug abuse, alcoholism, heavy smoker and high altitude.
Factors due to the foetus include congenital, genetic or chromosomal abnormalities, cerebral palsy, foetal infections and twins.
The usual factor due to the placenta is abruptio placentae (separation of the placenta from the uterus).
Investigations (eg. ultrasound scan, blood tests) will be undertaken to determine which cause is responsible.