Intrauterine Growth Restriction (IUGR)

2 Types of IUGR

1. Symmetrical IUGR: all parts of the baby's body are similarly small in size
2. Asymmetrical IUGR: the baby's head and brain are the expected size, but the rest of the baby's body is small

Causes of Intrauterine Growth Restriction (IUGR)

Often, IUGR happens because the fetus doesn't get enough nutrients and nourishment. This can happen if there is a problem with:

• The placenta, the tissue that brings nutrients and oxygen to the developing baby
• The blood flow in the umbilical cord, which connects the baby to the placenta

Intrauterine growth restriction also can happen if a pregnant woman:

• Smokes, drinks alcohol, or uses drugs
• Has an infection, such as cytomegalovirus, German measles (rubella), toxoplasmosis, or syphilis
• Takes some types of medicines, such as some seizure treatments
• Has a medical condition such as lupus, anemia, or clotting problems
• Has high blood pressure (hypertension)
• Is carrying a baby that has a genetic disorder or birth defect
• Is pregnant with multiples (such as twins or triplets)

What are the symptoms of intrauterine growth restriction?

Most people don’t have any symptoms or signs that the fetus is small for its gestational age. You may feel that your belly or the fetus isn’t as big as it should be. Even if you feel this way, only your healthcare provider can diagnose intrauterine growth restriction.

Testing and diagnosis

One of the main reasons for regular prenatal exams is to make sure your baby is growing well. During pregnancy, the size of your baby is estimated in different ways, including:

• Fundal height. To check fundal height, your healthcare provider measures from the top of your pubic bone to the top of your uterus (fundus). Fundal height, measured in centimeters (cm), is about the same as the number of weeks of pregnancy after the 20th week. For example, at 24 weeks gestation, your fundal height should be close to 24 cm. If the fundal height is less than expected, it may mean IUGR.
• Fetal ultrasound. Estimating fetal weight with ultrasound is the best way to find IUGR. Ultrasound uses sound waves to create images of the baby in the womb. Sound waves will not harm you or the baby. Your healthcare provider or a technician will use the images to measure the baby. A diagnosis of IUGR is based on the difference between actual and expected measurements at a certain gestational age.
• Doppler ultrasound. You may also have this special type of ultrasound to diagnose IUGR. Doppler ultrasound checks the blood flow to the placenta and through the umbilical cord to the baby. Decreased blood flow may mean your baby has IUGR.

Can I do anything to reduce the risk?

We don’t know why some pregnancies are affected by FGR and some are not. But it is unlikely to be related to anything you have done before or during pregnancy. It is important not to blame yourself. Some things that increase your risk of having a small baby can’t be changed. But there are some things you can do to reduce the risk, including:

• Stopping smoking
• Taking vitamin D
• Eating a healthy, balanced diet
• Not drinking alcohol
• Not using illegal/recreational drugs, especially cocaine.

If you are overweight, you are more likely to develop high blood pressure, which can cause complications leading to problems with the baby’s growth. It can help to maintain a healthy weight before and during pregnancy.

High levels of caffeine in pregnancy has been linked to low birthweight, as well as miscarriage. Try to limit your caffeine to 200 milligrams (mg) a day. This is about the same as 2 mugs of instant coffee.