Intrauterine Growth Restriction – Types, Causes And Risks by Dr Lathiesh Kumar Kambham

Causes Of Intrauterine Growth Restriction

The frequent causes of intrauterine growth retardation are listed as under:

• Pre-eclampsia
• Placental insufficiency
• Cardiovascular disease
• Unexplained elevated maternal alpha-fetoprotein level
• Idiopathic
• Chronic maternal disease
• Hypertension or diabetes
• Drinking alcohol or smoking
• Living in high altitudes
• Abnormal placentation
• Abruptio placenta, Placenta praevia, Placenta accretia, Circumvallate placenta
• Infarction
• Genetic disorders such as Turner’s syndrome, family history
• Hemangioma
• Chromosomal anomalies such as trisomy 13, 18 and 21
• Immunologic
• Infections such as rubella, herpes, cytomegalovirus, toxoplasmosis
• Antiphospholipid syndrome
• Metabolic
• Phenylketonuria
• Poor maternal nutrition, Low socioeconomic status
• Multiple gestations

Types Of Intrauterine Growth Restriction

There are two types of intrauterine growth restrictions.

1. Asymmetric IUGR

In this type of IUGR, the head circumference of the fetus is normal but the abdominal circumference is usually small, the limbs are lean and bony and the liver is small in size. The amount of abdominal fat is also less. The baby is disproportionately affected. The head is normal-sized but the remaining body is comparatively small

2. Symmetric IUGR

If the impact of asymmetric IUGR remains for long, the fetus is unable to match up to the growth loss and cannot recover and the obvious outcome is symmetric growth retardation. The overall growth is restricted and is a major developmental issue. In other words, the baby is proportionately small (all body parts are small)

Proper intrauterine fetal growth is dependent upon placental, maternal and genetic factors and under normal circumstances, the newborn has an appropriate size. The fetal-placental-maternal factors act in junction and unison to cater for the developmental needs of the growing fetus in the uterus. Growth restriction or suppression of the fetus is due to any disturbance in these three vital units (maternal-placental-fetal). The underlying reasons can be either environmental or intrinsic.

How Is Intrauterine Growth Retardation Detected?

Early diagnosis and proper management are the main factors in treating intrauterine growth retardation and thereby reducing perinatal morbidity. Fetal IUGR is an important cause of perinatal mortality and morbidity besides prematurity which is the leading cause.

1. Ultrasonography is the most authentic and reliable technique for assessing fetal growth and development.
2. The biparietal diameter (basic biometric parameters used to assess fetal size), abdominal circumference, head circumference and femur length are the main parameters involved in the assessment of IUGR.
3. The estimation of amniotic fluid is another important parameter for assessing IUGR. Diminishing amniotic fluid is related with IUGR and if it is less than 5 cm, significant fetal morbidity is seen. The amniotic fluid index is calculated by adding the largest cord-free pocket in four quadrants of equally divided uterus.

Management Of Intrauterine Growth Retardation

• Pregnant women with pre-eclampsia should be monitored for IUGR
• NST or non-stress test is done to assess the normal activity
• 24-hour urine sample is examined for protein content
• Hematological examination is done for platelet count and a liver function test is also done
• Antenatal steroids are given to encourage lung maturity
• Regular monitoring of blood pressure is done

Effects Of Intrauterine Growth Retardation

A myriad of effects is seen as a consequence of intrauterine growth impairment.

1. IUGR-affected fetuses suffer from altered cardiac functions in both diastolic and systolic phases
2. IUGR is considered a failure or an inability of a fetus to acquire genetic growth potential due to nutritional deprivation
3. IUGR also results in intrauterine demise due to chronic deprivation of oxygen
4. Preterm delivery is also a common consequence of growth-restricted fetuses
5. The most important threat predisposed by IUGR in infants is perinatal asphyxia affecting multiple organs
6. Retarded neurologic development is related to intrauterine growth retardation
7. Increased vulnerability to infant mortality and morbidity

Risk Factors Associated With Intrauterine Growth Restriction

It is seen that intrauterine growth retardation is common in women carrying more than one baby or those with previous IUGR pregnancies. Medical ailments such as lung, heart, blood or autoimmune conditions increase the threat or susceptibility of a woman to having IUGR pregnancy. Underweight mothers or poor appetites can also increase the risk for expectant mothers.

1. Intrauterine Growth Retardation And OCD

OCD is an obsessive-compulsive disorder defined as an anxiety disorder associated with unwanted uncontrolled thoughts and repetitive behaviour an individual is forced to perform. These obsessive thoughts and behaviors are irrational and difficult to resist. Growth retardation in fetal life predisposes the threat of OCD in later life. The reason is idiopathic. The lag in the development of fetal brain is attributed to obsessive-compulsive disorder.

2. Intrauterine Growth Retardation Complications

Babies with intrauterine growth retardation are likely to be affected by the following fatal complications.

• Increased chances of caesarean section
• Difficulty in breathing and feeding
• Babies having low blood sugar levels
• Difficulty in maintaining body temperature
• Preterm delivery
• Impaired ability to fight invading infections
• Raised likelihood of stillbirth
• Increased chances of babies being born with some neurological disorders
• IUGR can cause impairment of normal renal functions
• IUGR affects the infant neurodevelopment.

The dangerous complications associated with IUGR can be prevented by early diagnosis and adequate management. Planning in the correct time to deliver the baby is an ideal method to evade the harmful perinatal effects.

Intrauterine growth restriction is a pregnancy complication that has many consequences on the baby. Proper medical monitoring through pregnancy and precautions during delivery are extremely important.