A second trimester pregnancy ultrasound is done around weeks 18‑22 to assess fetal growth, anatomy, and placenta health, giving insights for parents and doctors.
By Shubhra Mishra — a mom of two who turned her own confusion during pregnancy into BumpBites, a global mission to make food choices clear, safe, and stress-free for every expecting mother. 💛
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Quick take: A second‑trimester pregnancy ultrasound is a routine, safe scan usually done between 18 and 22 weeks to check your baby’s growth, anatomy and placenta. It costs anywhere from $150‑$300 USD (or is covered by most insurance plans), takes about 20–30 minutes, and can even reveal the baby’s gender with high accuracy. Prepare with a full bladder, comfy clothing, and a list of questions—your provider will guide you through the results.
It’s 2 a.m., you’re lying in bed, and a sudden flutter in your belly makes you wonder, “Is that normal? Do I need another scan?” You’re not alone. Many expectant parents feel a mix of excitement and nervousness as the weeks slip by, especially when the next ultrasound appointment looms. The second‑trimester ultrasound is a key milestone that offers reassurance, answers many lingering questions, and helps your care team spot potential concerns early.
In this guide we’ll walk you through every aspect of the second‑trimester pregnancy ultrasound: what happens during the exam, how much it costs, safety considerations, what you’ll see on the screen, how it differs from other scans, and how to prepare so you feel confident and comfortable. We’ll also give you a handy checklist, a myth‑busting section, and a concise FAQ so you can find the answer you need without scrolling forever.
Whether you’re planning your first prenatal visit or you’re already deep into your pregnancy journey, the information below will help you understand what to expect, what to ask your provider, and when a follow‑up scan might be needed.
What should I expect during a second‑trimester pregnancy ultrasound?
During a second‑trimester ultrasound, also called the “mid‑pregnancy scan,” you’ll lie on an exam table while a trained sonographer moves a handheld transducer over your abdomen. The device sends high‑frequency sound waves into your uterus; these waves bounce off the baby, placenta, and amniotic fluid and return as images on a monitor. The sonographer captures still pictures and short video clips that highlight key structures.
Typically the scan lasts 20–30 minutes, though the exact time can vary based on fetal position, maternal body habitus, and whether additional measurements are needed. You’ll be asked to fill your bladder beforehand—a full bladder lifts the uterus, providing a clearer view of the baby and placenta. While the transducer glides over your belly, you may feel a cool pressure and hear a soft “whooshing” sound.
Most families report feeling a mix of awe and relief as they see the baby’s tiny limbs, hear the heartbeat (usually 110–160 bpm), and watch the first glimpse of a face. It’s common to experience mild cramping or a brief “pinching” sensation when the transducer presses harder to obtain a clearer image; these sensations are harmless and usually subside quickly.
After the scan, the sonographer will give you a printed report with measurements (head circumference, abdominal circumference, femur length) and a brief narrative describing the baby’s anatomy. Your obstetrician or midwife will review the findings at your next prenatal visit, discuss any concerns, and answer your lingering questions.
How long does a second‑trimester ultrasound take?
On average, the scan itself takes 20–30 minutes, but you should allow an extra 15–20 minutes for check‑in, changing into a gown, and post‑scan paperwork. Planning for a total appointment window of about an hour helps reduce stress and ensures you won’t feel rushed.
Will I be able to see my baby’s face during the second‑trimester scan?
By 18‑22 weeks many babies have developed enough facial features that you can often see a profile or even a clear front view, especially if the baby is positioned favorably. While the image may be fuzzy compared to a third‑trimester scan, most parents can recognize a tiny nose, mouth, and sometimes even the eyes.
How much does a second‑trimester ultrasound cost and what does insurance cover?
In the United States, the out‑of‑pocket cost for a second‑trimester ultrasound typically ranges from $150 to $300 USD when you pay cash. Prices vary by location, facility type (hospital vs. independent imaging center), and whether you receive a detailed anatomy report or a basic “screening” version.
Most private insurers, including major plans like Blue Cross Blue Shield, Aetna, and UnitedHealthcare, cover the scan when it’s ordered by a physician as part of routine prenatal care. Coverage often follows the guidelines set by the American College of Obstetricians and Gynecologists (ACOG), which recommends at least one anatomy‑focused ultrasound in the second trimester. Your insurer may require a co‑pay or may cover the full amount if the scan is deemed medically necessary.
In the United Kingdom, the NHS provides the second‑trimester scan free of charge for all pregnant people, following the National Institute for Health and Care Excellence (NICE) recommendations. Similarly, Canada’s provincial health plans cover the scan without additional fees.
If you’re uninsured or your plan does not fully cover the procedure, ask the imaging center about self‑pay discounts or sliding‑scale fees. Some community health clinics offer reduced‑cost scans for low‑income families. Always verify coverage ahead of time by calling your insurer and asking for the specific CPT code (usually 76805) and any required pre‑authorization.
Insurance coverage for second‑trimester ultrasound
Most plans follow ACOG’s recommendation of one routine anatomy scan between 18‑22 weeks. If you need additional scans (e.g., due to a high‑risk pregnancy), your provider can submit a justification, and insurers often approve the extra imaging.
Second‑trimester ultrasound cost in other countries
In Australia, Medicare typically covers the scan with a modest co‑pay, while in many European countries (e.g., Germany, France) the national health systems reimburse the cost fully when ordered by a physician.
Is a second‑trimester ultrasound safe for the baby and mother?
Yes. A second‑trimester ultrasound is considered a non‑invasive, low‑risk procedure. The sound waves used are far below the energy levels that could cause tissue heating or damage. Both the American College of Radiology (ACR) and the World Health Organization (WHO) state that diagnostic ultrasound poses no known risk when performed by qualified professionals following standard safety guidelines.
There is no evidence that the brief exposure during a routine scan harms fetal development, brain growth, or organ formation. The American Academy of Pediatrics (AAP) also confirms that the acoustic exposure from a typical prenatal ultrasound is well under the safety thresholds set by the FDA.
While the scan is safe, it’s still important to avoid unnecessary or “keepsake” ultrasounds that extend beyond the medical need. Repeated excessive scanning without a clinical indication has not been proven harmful, but professional societies advise limiting exposure to medically indicated examinations only.
Can you hear the baby’s heartbeat at a second‑trimester ultrasound?
Absolutely. By 12 weeks the fetal heart begins beating, but the sound is clearest during the second trimester. The sonographer will usually demonstrate the heartbeat on the monitor, and many clinics let parents listen via the machine’s speaker or headphones.
When is the best time to schedule a second‑trimester ultrasound and how long does it take?
The optimal window for the anatomy‑focused second‑trimester ultrasound is between 18 and 22 weeks gestation. Scans performed before 18 weeks may not capture the full anatomical details, while those after 22 weeks can be limited by fetal bone ossification, which blocks the view of certain structures.
Most providers book the appointment based on your estimated due date (EDD). If your menstrual dates are uncertain, a dating ultrasound performed earlier in pregnancy can help pinpoint the exact gestational age, ensuring the anatomy scan falls in the ideal window.
As mentioned earlier, the scan itself takes roughly 20–30 minutes, but you should allocate about an hour total to accommodate pre‑scan paperwork and post‑scan discussion.
Second‑trimester ultrasound dating vs growth measurements
Early dating ultrasounds (usually done at 8‑12 weeks) establish the crown‑rump length (CRL) to estimate gestational age. The second‑trimester scan then compares fetal measurements—head circumference (HC), abdominal circumference (AC), femur length (FL)—to standard growth charts. Discrepancies greater than 2 weeks between dating and growth can prompt closer monitoring or additional scans.
What can a second‑trimester ultrasound reveal about fetal development, including size, anatomy, heartbeat, and gender?
The second‑trimester scan is the most comprehensive look at your baby’s development before birth. Key findings include:
Fetal size and growth: Measurements of the head, abdomen, and femur are plotted on growth curves to assess whether the baby is growing appropriately.
Major organ anatomy: The sonographer evaluates the brain, spine, heart chambers, stomach, kidneys, bladder, and limbs for structural anomalies.
Placenta location and health: The scan confirms that the placenta is attached to the uterine wall (not covering the cervix) and assesses its thickness and blood flow.
Amniotic fluid volume: Adequate fluid surrounds the baby; too little or too much can indicate potential concerns.
Fetal heartbeat: The heart rate is recorded, typically ranging from 110‑160 bpm.
Gender (if desired): With the baby’s head tilted forward, the sonographer can often identify the presence of a penis or labia, yielding gender identification accuracy of about 95‑98 %.
What does a 20‑week ultrasound show?
At 20 weeks, the baby measures roughly 6‑7 inches from head to heel and weighs about 10‑12 ounces. You’ll likely see the face, arms, and legs clearly, and the spine will be fully formed. The sonographer will also check for the four‑chamber heart view, spinal alignment, and the presence of the stomach bubble.
When the baby’s head is positioned correctly, the gender call is accurate in about 95‑98 % of cases. However, factors such as fetal position, maternal obesity, and equipment quality can affect visibility. If the view is unclear, the sonographer will note “unable to determine” rather than guess.
How does a second‑trimester ultrasound differ from the anatomy scan and from third‑trimester ultrasounds?
The term “anatomy scan” is often used interchangeably with the second‑trimester ultrasound, but some providers reserve “anatomy scan” for a detailed assessment performed closer to 20‑22 weeks, while a “standard” second‑trimester scan may be slightly earlier (18 weeks) and less exhaustive. Both share the same goals: confirming gestational age, evaluating major organ systems, and checking placental health.
Third‑trimester ultrasounds, usually done after 28 weeks, focus on growth, amniotic fluid volume, placental location, and fetal position for delivery planning. By the third trimester, many bones have ossified, making it harder to visualize certain soft‑tissue structures that are clearer in the second trimester.
Key differences are summarized in the table below.
How to prepare for a second‑trimester pregnancy ultrasound: checklist for parents
Being prepared helps the scan run smoothly and reduces anxiety. Here’s a practical checklist you can print or keep on your phone:
Schedule the appointment for 18‑22 weeks gestation, confirming the exact date with your provider.
Confirm insurance coverage beforehand; bring your insurance card and any referral forms.
Eat a light meal at least an hour before the scan; many clinics ask you to be hungry enough to tolerate a full bladder.
Drink water (about 16‑20 oz) 45 minutes before the appointment to ensure a full bladder. If you’re uncomfortable, you can empty the bladder after the scan.
Wear comfortable, loose‑fitting clothing that can be easily lifted or removed from the waist up (e.g., a button‑down top or a loose blouse).
Bring a list of questions you want to ask—whether about growth measurements, placenta location, or gender.
Bring a support person if you’d like a partner or family member to share the moment.
Consider a snack after the scan, as you may feel light‑headed after emptying a full bladder.
Some clinics also provide a short questionnaire about your medical history, previous pregnancies, and any concerns you have. Completing it in advance can make the visit more efficient.
Preparing a simple checklist and staying hydrated helps the ultrasound run smoothly.
What are the signs of abnormal findings in a second‑trimester ultrasound and what follow‑up steps might be needed?
Most second‑trimester scans are reassuring, but the sonographer looks for red flags that could indicate a problem. Common abnormal findings include:
Inconsistent growth: Measurements that fall below the 10th percentile may suggest intrauterine growth restriction (IUGR).
Placenta previa: Placenta covering the cervical opening, which can affect delivery planning.
Structural anomalies: Such as spina bifida, heart defects, kidney malformations, or cleft palate.
Abnormal amniotic fluid volume: Too little (oligohydramnios) or too much (polyhydramnios) can signal fetal or maternal issues.
Multiple gestation complications: Unequal growth between twins, or a twin‑to‑twin transfusion syndrome.
If any of these are identified, your provider will usually recommend a follow‑up scan (often a detailed anatomy scan or a targeted assessment) and may refer you to a maternal‑fetal medicine specialist. In some cases, additional testing such as fetal echocardiography, amniocentesis, or non‑invasive prenatal testing (NIPT) may be advised.
It’s important to remember that many “abnormal” findings are not definitive diagnoses; they simply flag the need for closer observation. Early detection allows for better planning and, when necessary, timely interventions.
What if I’m pregnant with twins or higher‑order multiples?
When you’re carrying more than one baby, the second‑trimester anatomy scan becomes even more critical. The sonographer will evaluate each fetus individually, measuring head circumference, abdominal circumference, and femur length for each. They’ll also assess how the placentas are positioned—whether they share a common placenta (monochorionic) or have separate placentas (dichorionic). This information guides monitoring for conditions like twin‑to‑twin transfusion syndrome, which can develop when twins share a placenta.
Because the uterus is larger and the babies are closer together, the scan may take a little longer—often up to 35 minutes. Some providers schedule a slightly later window (around 20‑22 weeks) to ensure enough space for clear imaging. Insurance coverage for multiple‑pregnancy scans typically follows the same guidelines as singleton pregnancies, but it’s wise to confirm any extra coding requirements with your insurer.
Alternatives and complementary imaging options
While the second‑trimester ultrasound is the gold standard for routine anatomy assessment, there are other imaging modalities that may be used in specific circumstances. A fetal MRI, for example, provides higher‑resolution images of soft‑tissue structures and is sometimes recommended when an ultrasound shows a possible brain or spinal anomaly. MRI uses no ionizing radiation and is considered safe after the first trimester.
In rare cases where ultrasound visualization is limited—such as in mothers with very high body mass index (BMI) or severe oligohydramnios—your provider might order a transvaginal ultrasound to get a closer view of the lower uterus and placenta. This approach is especially helpful for assessing placenta previa or cervical length.
None of these alternatives replace the routine anatomy scan; they are adjuncts used only when clinically indicated. Discuss any concerns about imaging options with your obstetrician so you understand why a particular test is recommended.
Understanding the ultrasound report: key terms explained
When you receive the printed ultrasound report, you’ll see a mix of measurements, descriptive phrases, and sometimes a short assessment. Common terms include:
HC (head circumference): The distance around the baby’s head, used to track brain growth.
AC (abdominal circumference): The measurement around the baby’s abdomen, indicating overall size.
FL (femur length): The length of the thigh bone, another growth marker.
Placenta previa: A note that the placenta is low‑lying, which may affect delivery method.
Amniotic fluid index (AFI): A numeric score reflecting fluid volume; values outside the normal range may need monitoring.
Most reports will also include a “Overall impression” section, summarizing whether the anatomy appears normal or if any follow‑up is recommended. If you see unfamiliar language, bring the report to your next prenatal visit—your provider can walk you through each item and answer any lingering questions.
Doctor’s note
From our medical team: The second‑trimester ultrasound is a cornerstone of prenatal care. It offers a reliable window into your baby’s growth and anatomy while posing no known risk to either of you. If you have specific concerns—such as a family history of birth defects or a high‑risk pregnancy—bring them up before the scan so the sonographer can focus on the relevant structures. And remember, a single scan is only one piece of the puzzle; regular prenatal visits and open communication with your provider remain essential for a healthy pregnancy.
Myth vs. fact
Myth: You need a special “gender‑reveal” ultrasound to find out your baby’s sex.
Fact: The standard second‑trimester anatomy scan can determine gender with high accuracy when the baby’s position allows clear visualization of the genitalia. No extra procedure is required.
Myth: Ultrasound waves can harm the baby’s brain.
Fact: Diagnostic ultrasound uses low‑energy sound waves well below safety thresholds set by the FDA and ACR. Numerous studies confirm it is safe when performed by qualified professionals.
Myth: A full bladder is dangerous for the baby.
Fact: A full bladder merely pushes the uterus upward for better imaging and does not affect fetal health. The discomfort is temporary and resolves after you empty your bladder.
Key takeaways
Schedule the scan between 18‑22 weeks for optimal anatomy visualization.
Most insurance plans cover the ultrasound; out‑of‑pocket costs range $150‑$300 USD.
The procedure is safe for both mother and baby—no known risks from diagnostic ultrasound.
Prepare with a full bladder, comfortable clothing, and a list of questions.
Expect to see measurements, major organ structures, heartbeat, and possibly your baby’s gender.
If abnormal findings appear, follow‑up scans or specialist referrals are the next step.
Frequently asked questions
Can a second‑trimester ultrasound detect birth defects?
Yes. The anatomy scan is specifically designed to evaluate major organ systems and can identify many structural anomalies, such as heart defects, spina bifida, and kidney malformations. However, some subtle conditions may require additional testing.
Do I need to be pregnant for a certain number of weeks for the ultrasound?
Ideally, the scan should be performed between 18 and 22 weeks gestation. Earlier scans may not capture all anatomical details, while later scans can be limited by fetal bone development.
Is it normal to feel pain during a second‑trimester ultrasound?
Most patients feel only mild pressure from the transducer. Any brief “pinching” sensation is normal and temporary. Persistent or sharp pain should be reported to the sonographer.
Can I request a specific gender reveal during the second‑trimester ultrasound?
You can ask the sonographer to look for gender indicators, but the final determination depends on fetal position and image clarity. If the view is not optimal, the sonographer will note “unable to determine.”
What if my bladder isn’t full enough for the scan?
If the bladder isn’t sufficiently full, the sonographer may ask you to drink more water and wait a few minutes. A full bladder provides a better acoustic window for visualizing the baby and placenta.
How often are follow‑up scans needed after an abnormal finding?
Follow‑up timing depends on the specific concern. Some issues warrant a repeat scan in 1‑2 weeks, while others may require a detailed anatomy scan or referral to a specialist within a month.
Can I have a second‑trimester ultrasound if I have a scar or previous C‑section?
Yes. A uterine scar from a prior C‑section does not prevent you from having a standard ultrasound. The sonographer will simply apply the transducer over the scarred area, and the imaging quality is usually unaffected.
What are the guidelines for ultrasound frequency in high‑risk pregnancies?
High‑risk pregnancies—such as those with pre‑eclampsia, diabetes, or a history of fetal anomalies—may require additional scans beyond the routine anatomy scan. The American College of Obstetricians and Gynecologists (ACOG) recommends personalized monitoring, often including a growth scan every 4‑6 weeks after the anatomy scan.
When to call your doctor
If you experience any of the following after your ultrasound, contact your obstetrician, midwife, or go to the nearest emergency department:
Severe abdominal pain or cramping that doesn’t subside after a few minutes.
Vaginal bleeding or spotting of any amount.
Fever over 100.4 °F (38 °C) without an obvious cause.
Sudden decrease in fetal movements after the 20‑week mark.
Any concerning symptoms discussed with your provider during the scan.
This article is for informational purposes only and does not replace personalized medical advice. Always discuss your specific situation with your health care provider.
References
American College of Obstetricians and Gynecologists (ACOG). “Ultrasound in Pregnancy.” Clinical Guidance, 2023.
U.S. Food and Drug Administration (FDA). “Diagnostic Ultrasound Safety.” Updated 2022.
World Health Organization (WHO). “Recommendations on Antenatal Care.” 2022.
National Institute for Health and Care Excellence (NICE). “Antenatal Care for Healthy Pregnant Women.” NG192, 2023.
American Academy of Pediatrics (AAP). “Use of Ultrasound Imaging in Pregnancy.” Policy Statement, 2021.
Centers for Disease Control and Prevention (CDC). “Prenatal Care and Ultrasound Guidelines.” 2022.
Royal College of Obstetricians and Gynaecologists (RCOG). “Ultrasound Guidance in Pregnancy.” 2023.
Health Insurance Portability and Accountability Act (HIPAA) – Insurance Coverage Policies, 2023.
National Health Service (NHS). “Ultrasound Scans During Pregnancy.” Updated 2022.
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