Pregnancy is a time filled with excitement, questions, and regular health check-ups. One of the most important tools doctors use to monitor pregnancy is ultrasound. It provides valuable information about the developing baby and the pregnancy without using radiation.
A pregnancy ultrasound can help confirm the pregnancy, determine how far along you are, check the baby’s heartbeat, assess growth and development, and identify certain potential concerns.
But does every pregnancy require the same number of ultrasounds? What does each scan show, and when is it usually performed?
Let’s understand the role of pregnancy ultrasound at different stages of pregnancy.
What Is a Pregnancy Ultrasound?
A pregnancy ultrasound, also called an obstetric ultrasound, uses high-frequency sound waves to create images of the uterus, placenta, amniotic fluid, and developing baby.
Unlike X-rays, ultrasound does not use ionizing radiation. When medically indicated and performed by trained professionals, it is widely used during pregnancy.
Depending on the stage of pregnancy and the purpose of the examination, the ultrasound may be performed through the abdomen or, particularly during early pregnancy, through the vagina using a specialized probe.
When Is a Pregnancy Ultrasound Needed?
The timing and number of ultrasounds can vary depending on the pregnancy, medical history, symptoms, and recommendations of the treating doctor.
Some common scans include:
1. Early Pregnancy Ultrasound
An ultrasound may be recommended during early pregnancy to:
- Confirm that the pregnancy is located inside the uterus
- Establish or confirm gestational age
- Assess fetal viability
- Detect the baby’s heartbeat when appropriate for the gestational age
- Check the number of embryos or fetuses
- Evaluate symptoms such as bleeding or pelvic pain
An early scan can be particularly useful when the dates of the last menstrual period are uncertain or when there are symptoms that require evaluation.
2. Dating Scan
A dating ultrasound may be used to estimate the gestational age of the pregnancy.
Accurate pregnancy dating is important because it helps doctors determine expected milestones and interpret later growth and screening results appropriately.
In some cases, the estimated due date based on the menstrual history may be adjusted based on ultrasound findings, particularly when there is uncertainty about the dates.
3. First-Trimester Screening Ultrasound
During the first trimester, an ultrasound may be performed as part of screening for certain chromosomal conditions.
One commonly known examination is the nuchal translucency (NT) scan, usually performed during a specific window in early pregnancy.
The scan assesses the thickness of the fluid collection at the back of the baby’s neck along with other ultrasound findings. It is often combined with maternal blood tests to provide a screening assessment.
It is important to remember that screening tests estimate risk; they do not by themselves diagnose a chromosomal condition.
4. Anomaly or Level-II Scan
One of the most detailed pregnancy ultrasounds is the anomaly scan, commonly performed around the middle of pregnancy.
It evaluates the baby’s anatomy and examines structures such as:
- Brain
- Face
- Spine
- Heart
- Abdomen
- Kidneys
- Bladder
- Limbs
The placenta, amniotic fluid, fetal growth, and other pregnancy-related structures are also assessed.
The purpose is to identify certain structural abnormalities that may be visible on ultrasound.
However, no ultrasound can detect every possible birth defect or health condition.
5. Growth Ultrasound
A growth scan may be recommended later in pregnancy when the doctor wants to assess the baby’s growth and wellbeing.
It can help evaluate:
- Estimated fetal weight
- Measurements of the baby’s head, abdomen, and thigh bone
- Amniotic fluid
- Placental location and appearance
- Fetal position
- Growth pattern over time
Growth scans may be particularly useful when there are concerns about fetal growth, maternal health conditions, placental problems, or other pregnancy-related factors.
What Does a Pregnancy Ultrasound Show?
The information obtained from an ultrasound depends on the gestational age and purpose of the examination.
A pregnancy ultrasound may provide information about:
Baby’s Growth
Measurements of different parts of the baby’s body can help assess growth and estimate fetal weight.
Baby’s Heartbeat
When the pregnancy is sufficiently advanced, ultrasound can demonstrate fetal cardiac activity.
Baby’s Position
Later in pregnancy, ultrasound can show whether the baby is head-down, breech, or in another position at the time of the examination.
Placenta
The scan can assess the location of the placenta and identify certain placental abnormalities that may require further monitoring.
Amniotic Fluid
The amount of amniotic fluid can be assessed as part of pregnancy monitoring.
Multiple Pregnancy
Ultrasound can identify twins or other multiple pregnancies and help determine important features of the pregnancy.
Fetal Anatomy
Detailed ultrasound examinations can assess many fetal organs and body structures and may identify certain structural abnormalities.
Is Pregnancy Ultrasound Safe?
Ultrasound has been used extensively in pregnancy and does not involve ionizing radiation.
However, this does not mean that scans should be performed unnecessarily. Pregnancy ultrasounds should be performed when medically appropriate, using suitable equipment and settings and by trained professionals.
The number and timing of scans should therefore be based on your individual pregnancy and your doctor’s recommendations.
Does Every Pregnant Woman Need the Same Ultrasounds?
No.
Pregnancy care is individualized. A woman with an uncomplicated pregnancy may have a different ultrasound schedule from someone who has:
- High blood pressure
- Diabetes during pregnancy
- Previous pregnancy complications
- Vaginal bleeding
- Concerns about fetal growth
- Multiple pregnancy
- Placental abnormalities
- Uncertain pregnancy dates
- Other maternal or fetal concerns
Your obstetrician or healthcare provider will recommend scans based on your specific circumstances.
What Should You Do Before a Pregnancy Ultrasound?
Preparation depends on the type of ultrasound and the stage of pregnancy.
For some early pregnancy scans, a partially full bladder may sometimes be recommended to improve visualization. For many later pregnancy scans, special preparation may not be necessary.
It is best to follow the instructions provided by your healthcare provider or diagnostic centre before the examination.
What Happens During the Ultrasound?
For an abdominal ultrasound, you generally lie comfortably on an examination bed while a small amount of ultrasound gel is applied to the abdomen.
The sonologist or radiologist moves a transducer over the abdomen to obtain images.
During early pregnancy, a transvaginal ultrasound may sometimes be recommended. A specially designed probe is gently inserted into the vagina to obtain clearer images of the uterus and early pregnancy.
The choice of approach depends on the stage of pregnancy and the clinical reason for the examination.
Can an Ultrasound Tell If the Baby Is Completely Healthy?
An ultrasound provides important information, but it cannot guarantee that a baby has no health problems.
Some structural abnormalities can be detected during detailed scans, while others may not be visible. Certain genetic, developmental, metabolic, or functional conditions may require additional testing or may not be detectable through ultrasound.
This is why prenatal care may include a combination of medical history, physical examinations, blood tests, ultrasound, and other investigations when indicated.
When Should You Contact Your Doctor During Pregnancy?
While routine pregnancy ultrasounds are scheduled according to individual needs, certain symptoms should not be ignored.
Contact your healthcare provider if you experience symptoms such as:
- Vaginal bleeding
- Persistent or severe abdominal pain
- Leakage of fluid
- Severe headache or visual changes
- Significant swelling or other concerning symptoms
- Reduced fetal movements later in pregnancy
Seek urgent medical care when symptoms are severe or your doctor has advised you to do so.
Frequently Asked Questions
When is the first pregnancy ultrasound usually done?
The timing varies depending on the pregnancy and clinical circumstances. An early ultrasound may be recommended to confirm the location and viability of the pregnancy and establish gestational age.
How many ultrasounds are needed during pregnancy?
There is no fixed number that applies to every woman. The schedule depends on the pregnancy, medical history, symptoms, and findings from previous examinations.
Is ultrasound during pregnancy painful?
Abdominal ultrasound is generally painless. A transvaginal ultrasound may cause some pressure or mild discomfort but is usually well tolerated.
Can ultrasound determine the baby’s gender?
Ultrasound may sometimes show fetal sex depending on gestational age, fetal position, image quality, and local laws and regulations. In India, disclosure of fetal sex for the purpose of sex selection is prohibited under the PCPNDT Act.
What is the difference between a normal ultrasound and an anomaly scan?
A routine ultrasound may focus on specific pregnancy parameters such as growth, viability, or fluid levels. An anomaly scan is a more detailed examination of fetal anatomy performed during the appropriate stage of pregnancy.
Conclusion
Pregnancy ultrasound is an important part of prenatal care and can provide valuable information about your baby’s growth, development, heartbeat, position, placenta, and overall pregnancy status.
From an early pregnancy scan to the detailed anomaly scan and later growth assessments, each ultrasound has a specific purpose. However, not every woman needs the same scans or the same frequency of monitoring.
The best approach is to follow an individualized pregnancy-care plan recommended by your obstetrician and qualified imaging specialist.
If you are pregnant or planning a pregnancy and have questions about which ultrasound scans you may need, consult Dr. Gazal Garg for personalized guidance and appropriate prenatal imaging.
