Prenatal testing and screening are essential parts of pregnancy care. These tools help monitor both maternal health and fetal development, providing valuable information to guide clinical decisions and ensure the safest outcomes. Whether confirming a due date or screening for genetic concerns, timely testing can help expectant parents feel informed and supported.
At Columbus OB/GYN, we provide comprehensive prenatal care that includes genetic testing during pregnancy, ultrasound screening, and diagnostic evaluations in all three trimesters. Our experienced team ensures that every woman receives individualized guidance based on her medical history and needs.
Here’s what you can expect throughout your prenatal screening timeline and how our team is here to support you at every stage.
Why Prenatal Testing Matters
Every pregnancy is unique. Prenatal testing allows for early identification of potential concerns, many of which can be managed more effectively the sooner they are found. These tests serve multiple purposes: to assess the baby’s health, track maternal wellness, measure fetal growth, and check for specific risk factors that may affect the pregnancy.
Prenatal assessments can be separated into two main categories:
- Screening tests, which estimate the chance of certain genetic or developmental conditions. These are often noninvasive and part of routine care.
- Diagnostic tests, which confirm whether a specific condition is present. These are typically offered based on screening results, maternal age, or family history.
While these options can feel overwhelming at first, rest assured—all testing performed at Columbus OB/GYN is safe and patient-centered. We’ll walk you through the process, explain your choices, and help you understand what each result means.
First Trimester Testing (Weeks 0-13)
The first trimester lays the foundation for your prenatal care. Initial screenings provide early insights and help plan the remainder of your pregnancy journey. Most patients begin care between weeks 6 and 8, when testing begins.
At your first visit, we typically perform several baseline labs:
- A complete blood count (CBC) to check for anemia or infection
- Blood type and Rh factor are used to identify possible blood incompatibilities between mother and baby
- Infectious disease screening for conditions such as HIV, hepatitis B and C, syphilis, and rubella immunity
Around weeks 11 to 13, the first trimester screening focuses more on the baby. Two common options include:
- Nuchal translucency ultrasound: Measures the fluid at the back of the baby’s neck. When combined with bloodwork, this screening can assess the risk of chromosomal conditions.
- Non-invasive prenatal testing (NIPT): This advanced blood test analyzes cell-free fetal DNA circulating in the mother’s blood. It’s a highly accurate way to detect chromosomal abnormalities like Down syndrome, trisomy 18, and trisomy 13.
Both tests are safe and do not affect the baby. While NIPT is not diagnostic, it is considered one of the most reliable first-trimester screening tools.
These evaluations help detect early concerns and allow time for more precise diagnosis if needed. If anything atypical appears, we discuss follow-up testing or referrals—with your input guiding the path forward.
Learn more about our Ultrasound services.
Second Trimester Testing (Weeks 14–27)
As your baby grows, second-trimester screenings provide even greater insight into development and maternal health. This stage includes some of the most informative testing in the prenatal timeline.
One key second-trimester screening occurs between weeks 15 and 20:
- The quad screen measures four substances in your blood. It assesses the risk for conditions such as spina bifida, Down syndrome, and trisomy 18. While not diagnostic, it may identify pregnancies that need further testing.
By weeks 18 to 22, all patients typically undergo an anatomy ultrasound. Sometimes called a fetal survey, this imaging test checks major organs, limbs, placenta location, and amniotic fluid. It’s a key part of ultrasound screening during pregnancy and can detect structural abnormalities.
In some cases, your provider may recommend amniocentesis. This diagnostic test is usually performed after week 15 if prior screenings indicate a higher risk for genetic conditions. During the procedure, a small sample of amniotic fluid is collected under ultrasound guidance. While slightly more invasive, amniocentesis offers definitive diagnostic information and is performed with great care.
If you are carrying twins or multiples, or if there are other complexities, we may increase the frequency of your visits. More frequent ultrasounds help us monitor growth patterns and screen for complications, making sure you and your baby remain healthy.
Third Trimester Testing (Weeks 28-40)
As your due date approaches, third-trimester screening focuses largely on maternal health, fetal growth, and labor preparation. Ongoing monitoring during this time helps us address any last-minute changes or concerns.
Between weeks 24 and 28, many patients receive the glucose tolerance test to screen for gestational diabetes. This test measures how your body processes sugar and determines whether further evaluation is needed.
Another important evaluation occurs between weeks 35 and 37—the group B strep test. This simple vaginal and rectal swab screens for the bacteria Group B Streptococcus. If present, we plan for antibiotics during labor to protect the baby from infection.
In pregnancies with any increased risk factors, we may conduct additional growth ultrasounds. These help us ensure your baby is developing normally and allow us to assess the placenta, amniotic fluid levels, and fetal position.
Beginning around 36–37 weeks, most patients begin weekly appointments. These visits may include:
- Cervical checks for dilation
- Monitoring for signs of labor
- Non-stress tests (NSTs) are used in certain cases to track fetal movement and heart rate
Timely third-trimester testing helps ensure both mother and baby are ready for labor, and any final adjustments in your care plan are made with confidence.
Discover labor prep information on our Pregnancy & Childbirth service.
What Results Mean and Your Next Steps
Interpreting screening results is a key part of prenatal care. It’s important to remember that most tests are screening tools. A positive result does not mean your child has a condition—rather, it simply means additional testing may be recommended.
For example, an abnormal result from a quad screen may lead to a more detailed ultrasound or possibly an amniocentesis. Similarly, if NIPT shows a higher-than-expected risk, your provider will talk through your options with clarity and compassion.
We take the time to explain results in simple language, review potential concerns, and answer your questions. No matter the outcome, our providers help you navigate the next steps with professionalism and empathy.
Partnering with Columbus OB/GYN
At Columbus OB/GYN, we are committed to supporting you—not just during testing, but throughout your entire pregnancy. Our care model ensures consistency: from your first prenatal visit through ultrasound screenings, delivery, and postpartum care.
We offer:
- Comprehensive testing, including non-invasive prenatal testing (NIPT), genetic testing, and ultrasound screening in pregnancy
- Expertise in first, second, and third trimester screening and diagnostic care
- Locations throughout Columbus, OH, for convenient access and continuity of care
Whether you’re just starting to plan for a baby or are in your third trimester, we’re ready to meet you where you are.
Schedule your prenatal appointment today.
Frequently Asked Questions
What’s the difference between a screening test and a diagnostic test?
A screening test shows the chances of a condition being present; it does not confirm it. A diagnostic test can establish whether a condition exists.
Is prenatal genetic testing safe?
Yes. Most prenatal genetic tests—such as NIPT—are noninvasive and pose no risk to you or your baby. Diagnostic tests like amniocentesis are also safe when performed by experienced providers.
Do all pregnant women need the same tests?
Not necessarily. Testing depends on your age, health history, pregnancy type, and personal preferences. Your provider will recommend what makes sense for your individual situation.
Can I decline a prenatal test?
Yes. All tests are optional. We’ll provide the information you need to make the right choice for yourself and your family.