Poor fetal growth, also called intrauterine growth restriction or IUGR, is diagnosed when a baby in the womb is too small for its gestational age. According to the March of Dimes, about 10 percent of fetuses suffer from poor fetal growth and this is a major contributor to low birth weight.
Types
According to the American Pregnancy Association, there are two types of poor fetal growth. In about 20 to 25 percent of cases, all of the organs of the body experience restricted growth and the baby is proportional but too small. This is called primary or symmetric growth restriction. In most cases, however, the head and brain grow at a normal rate for the gestational age and the rest of the body is disproportionately smaller, a condition called secondary or asymmetric growth restriction.
Causes
Intrauterine growth restriction occurs when the fetus cannot get enough nutrition from the mother or cannot properly process the nutrients it does receive. Poor fetal growth may be the result of maternal problems such as high blood pressure or pre-eclampsia. In the case of multiple fetuses, one or more of the babies may monopolize the nutrients, causing IUGR in siblings in the womb. Congenital problems in the baby and problems with the placenta or umbilical cord are other possible causes. Some infections or nutritional deficiencies in the mother may lead to poor fetal growth.
Diagnosis
During routine prenatal exams, a doctor may suspect intrauterine growth restriction if the uterine fundal height, the measure of how far up the uterus has risen, seems too low for that stage of pregnancy. An ultrasound may also be used to diagnose IUGR. If poor fetal growth is found, the doctor will look for the cause via ultrasounds, blood tests or genetic screening. An accurate assessment of fetal age is essential to determining whether a baby is experiencing poor fetal growth
Complications
Babies who grow poorly in the womb are more likely to have complications during and after birth. There is an increased risk of stillbirth associated with IUGR. Babies who do survive birth are typically diagnosed with low birth weight and suffer problems including lower immunity, low blood sugar, high red blood cell count and difficulty maintaining body temperature. Infants who suffered from poor fetal growth may feel long-term aftereffects including developmental delays and have a higher incidence of stroke, hypertension, coronary heart disease and Type 2 diabetes as adults.
Treatment
Treatment for poor fetal growth involves treating the underlying problem that is causing it. In some cases, this simply means adjusting the mother's diet or providing medication or lifestyle changes that may ease disorders such as high blood pressure. In other cases, such as IUGR caused by placental abnormalities, there is no way to affect the underlying disorder and the mother and baby are monitored to determine the best course of action. Often, the baby will be delivered early via cesarean section, but the doctor must balance the risks involved with continued poor growth against those inherent in premature delivery.
References
- Medline Plus: Intrauterine Growth Restriction
- American Pregnancy Association: Fetal Growth Restriction
- American Academy of Family Physicians Family Doctor: Intrauterine Growth Restriction
- Clinical Obstetrics and Gynecology:Adult consequences of fetal growth restriction
- March of Dimes: Low Birthweight
