Fetal Growth Scan at 28–32 Weeks: A Comprehensive Guide

A fetal growth scan is a vital part of prenatal care, performed between 28 and 32 weeks of pregnancy. This scan provides essential insights into the baby’s health, development, and overall well-being during the late stages of the second trimester and early third trimester.  By uncovering potential complications, it enables early intervention and specialized care, ensuring better outcomes for both mother and child. In this article we shall explore why this scan is essential, what it reveals about your baby, potential concerns it can highlight, and how to proceed after a concerning outcome. Additionally, we will break down the process step-by-step to demystify what happens during this examination.  

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Why Is the Scan Done?

The purpose of the fetal growth scan is to assess how the baby is growing and ensure that development is progressing as expected. It is particularly important for:

• Evaluating fetal size and growth trajectory.
• Monitoring pregnancies with risk factors such as maternal hypertension, diabetes, or previous pregnancy complications.
• Checking for structural abnormalities that may not have been detectable earlier.
• Assessing placental function and amniotic fluid levels.

What Does the Scan Reveal About the Baby?

The growth scan provides detailed information on several key aspects of fetal health:

• Fetal Size and Growth Trends: Measurements of the head circumference (HC), abdominal circumference (AC), and femur length (FL) are taken to estimate the baby’s weight and growth pattern.
• Amniotic Fluid Volume: Ensures adequate fluid levels for fetal movement and lung development.
• Placental Position and Function: Checks for placental abnormalities like placenta previa or signs of insufficiency.
• Fetal Movement and Activity: Observes activity levels as an indicator of well-being.
• Doppler Flow Studies: Evaluates blood flow in the umbilical cord and brain, ensuring proper oxygen and nutrient delivery.

Why Is It an Important Scan?

The scan is pivotal because it can identify potential complications that may require medical intervention. Detecting issues early allows healthcare providers to plan appropriate care strategies to optimize outcomes for both mother and baby.

How many times is the scan needed?

In most cases, where the scan gives a normal outcome, only one scan is needed. but there are some women who may need more than one scan. Here are some reasons why additional growth scans may be necessary:

• If there is a history of complications in a previous pregnancy.
• In case of a prior C-section, the doctor may need to examine the scar tissue to determine and plan the appropriate type of delivery.
• Cases of multiple pregnancies (e.g., twins or triplets), require more frequent scans to monitor their growth.
• If the woman has Gestational conditions such as diabetes.
• A belly size that appears smaller or larger than expected based on gestational age.

Possible Outcomes of a Growth Scan

Let’s understand what the results of a growth scan could be. Normal Outcome: This is the most reassuring result. Every parent-to-be looks forward to hearing from the doctor that their baby is growing as expected. A normal outcome indicates that the baby’s organs are developing appropriately, the estimated fetal weight falls within the healthy range, and there are no concerns. It’s a moment of relief and joy. Small for Gestational Age (SGA): While many smaller babies are born healthy, a size below the normal range can sometimes indicate a condition known as fetal growth restriction. In such cases, the doctor may recommend additional growth scans to monitor the baby’s progress closely. Further tests, such as amniocentesis or an umbilical doppler, might also be suggested to investigate the cause of restricted growth. Large for Gestational Age (LGA): Most larger-than-average babies are also born healthy, but this deviation requires careful monitoring. If the baby continues to grow beyond expected limits as the pregnancy progresses, the doctor may recommend additional tests and closer observation. In some cases, persistent large size near the end of pregnancy may necessitate a cesarean section for a safe delivery.  

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Other Issues or Red Flags Detected

During this scan, doctors may identify:

• Intrauterine Growth Restriction (IUGR): Baby growing slower than expected.
• Macrosomia: Baby growing larger than expected, which may complicate delivery.
• Placental Abnormalities: Signs of poor placental function or unusual placement.
• Oligohydramnios or Polyhydramnios: Abnormal amniotic fluid levels.
• Congenital Anomalies: Late-detected physical abnormalities.
• Abnormal Doppler Results: Indicating compromised blood flow and potential distress.

Next Steps After Concerning Outcomes

If the scan reveals concerning findings:

1. Further Tests: May include non-stress tests, biophysical profiles, or repeat ultrasounds.
2. Close Monitoring: Increased frequency of scans or hospital visits to ensure fetal well-being.
3. Specialized Care: Referral to a maternal-fetal medicine specialist or initiation of treatment plans.
4. Early Delivery: In some cases, labor may be induced or a cesarean planned if the baby is in distress or the mother’s health is at risk

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