Intrauterine growth restriction (IUGR) is a common complication of pregnancy in developing countries, and carries an increased risk of perinatal mortality and morbidity. IUGR refers to a condition in which foetus (an unborn baby) is smaller or less developed than normal for the baby's gender and gestational age. Gestational age is the age of a foetus or baby that starts on the first day of the mother's last menstrual period.
In IUGR foetal weight is below the 10th percentile for gestational age as estimated by an ultrasound. At term, the birth weight less than 2,500 g (5lb, or 8oz) is considered as IUGR. Small for gestational age or fetal growth restriction are the other terms used for IUGR. The term intrauterine growth restriction has largely replaced the term intrauterine growth retardation.
IUGR is classified into two types-
Intrauterine growth restriction is observed in about 24% of newborns. In Asia IUGR accounts for nearly 75% of all affected infants. After prematurity IUGR is the second leading cause of perinatal morbidity and mortality.
Growth-restricted pregnancies are often complicated by a high rate of antepartum and intrapartum fetal distress and the need for cesarean delivery. These infants have many acute neonatal problems that include perinatal asphyxia, hypothermia (low body temperature), hypoglycemia (low blood sugar), and polycythemia (increased red blood cells), jaundice, feeding difficulties, feed intolerance, necrotizing enterocolitis, late-onset sepsis, and pulmonary hemorrhage.
When IUGR infants grow up long-term complications include growth retardation, neurodevelopment defects may occur. These infants are more likely to develop adult onset diseases because of fetal epigenetic changes.
Timely diagnosis (by assessment of fetal growth at each prenatal visit) and management of IUGR are the major activities in reducing perinatal morbidity and mortality.
The main symptom of IUGR is a small for gestational age baby. During the antenatal checkup, a doctor measures the height of the uterus from the pubic bone to estimate the size of the fetus. After about the 20th week, uterine fundal height in centimeters is usually equal to the number of weeks of the pregnancy. A lag in fundal height of 4 cm or more with weeks of pregnancy suggests IUGR, and additional tests are required to confirm diagnosis.
During ultrasound, the baby's estimated weight with IUGR is below the 10th percentile or less than that of 90% of babies of the same gestational age. At term, the birth weight less than 2,500 g (5 lb, 8 oz) is considered as IUGR. Not all babies that are born small have IUGR. In most severe cases IUGR can lead to stillbirth.
At term birth, symptoms of IUGR are:
IUGR has many causes related to mother, foetus and placenta (part that joins the mother and foetus). Various risk factors for IUGR can be summarized as-
A. Maternal causes –
B. Uterine and placental factors:
C. Fetal causes include familial genetic and chromosomal abnormalities and intrauterine infections such as TORCH- which includes toxoplasmosis, other infections (syphilis, varicella-zoster, parvovirus B19), rubella, cytomegalovirus (CMV), and herpes infections.
Symmetric or primary IUGR is due to genetic or chromosomal causes, early gestational intrauterine infections (TORCH) and maternal alcohol use.
Asymmetric IUGR is more commonly due to extrinsic influences that affect the foetus later in gestation, such as preeclampsia, chronic hypertension, and uterine anomalies.
One of the most important things when diagnosing IUGR is to know accurate gestational age of baby. Gestational age can be calculated by using the first day of last menstrual period (LMP) and also by early ultrasound calculations. Once the gestational age is known the following methods can be used to diagnose IUGR.
Fundal height: It is the simplest and most common method to diagnose IUGR. Fundal height is size of uterus measured as the distance from the pubic bone to the top of the uterus in centimeters. After the 20th week of pregnancy, the measure in centimeters usually corresponds with the number of weeks of pregnancy. A lag in fundal height of 4 cm or more suggests IUGR.
Weight checkups: Doctors routinely check and record the mother's weight at every prenatal checkup. If a mother is not gaining weight properly, it could indicate a growth problem in her baby.
Ultrasound: It is used to measure the baby's head and abdomen and compared with growth charts to estimate the baby's weight. Ultrasound can also be used to determine amniotic fluid.
Doppler assessment: It is a technique that uses sound waves to measure the amount and speed of blood flow through the blood vessels. Doctors may use this test to check the flow of blood in the umbilical cord and vessels in the baby's brain. Abnormal Doppler tests are diagnostic of IUGR.
General management measures: These include treatment of maternal disease, good nutrition and advice for bed rest.
Preterm delivery is indicated if the fetus shows evidence of abnormal function on biophysical profile testing. Antenatal administration of steroids in preterm pregnancies and delivery at an institution with an emergency obstetric care and neonatal care unit is advised.
The foetus should be monitored continuously during labor to minimize fetal hypoxia.
IUGR causes many health problems during pregnancy, delivery, and after birth. These include:
Although IUGR can occur even when a mother is perfectly healthy, still there are some measures to reduce the risk of IUGR and increase the chances of a healthy pregnancy and baby.
Care before pregnancy:
Care during pregnancy:
Care during delivery-