IUGR is a condition in which the fetus does not grow adequately. IUGR may be associated with diabetes, fetal infection, cigarette smoking, hypertension, drug abuse, toxemia, multiple gestation or may be due to reasons unknown. In any case, the fetus is not receiving adequate nutrition or is unable to make use of the nutrition s/he is receiving. Often with IUGR the placenta is small and may contain infarcts (areas of dead tissue).
IUGR is a problem which generally begins to emerge after the 30th week of pregnancy. If your doctor or midwife suspect IUGR, they will immediately try to determine that the fetus is receiving adequate oxygen (by evaluating fetal heart rate patterns). S/he will also establish a baseline of fetal measurements (with ultrasound). A single ultrasound scan is not very good at determining fetal weight, which would be very useful since norms for weights at all gestational ages have been well-established. But serial ultrasound scans (a series of ultrasounds over a period of weeks) can be used to determine if the baby is growing adequately. Unfortunately, a period of at least 2 weeks must past before successive ultrasounds can measure significant growth in the third trimester. And although ultrasound is limited in its ability to determine accurate fetal weights, the ultrasound’s “opinion” may be factored in on the decision-making process.
If, at any point, it is determined that the baby is in a “hostile environment”, the delivery process should be initiated, by either labor induction or c-section. This hostile environment is interpreted to be one in which the baby is not receiving adequate nutrition or worse, adequate oxygenation. The question of whether or not to deliver the baby is considered at the risk of prematurity……the dilemna hangs on which is the lesser of two evils. If the placenta is not doing its job, or is about to quit completely, the baby can die…..stillbirth. Hopefully, well before this point, the baby and placenta have given clues that something is not right.