Pregnancy comes with more tests than many people expect.
Before almost every appointment, I found myself searching for the same practical information:
- Do I need to fast?
- Should I arrive with a full bladder?
- How long will the appointment take?
- What exactly are they checking?
- Does a repeat test mean that something is wrong?
Some tests require only a quick blood draw. Others involve a detailed ultrasound that can take much longer if the baby is not in a cooperative position.
Because I was pregnant at age 40, I received additional monitoring through a maternal-fetal medicine specialist, often called an MFM. My testing schedule may therefore have been different from that of someone with a low-risk pregnancy.
Here is what to expect from the most common prenatal tests during the first and second trimesters.
This article is based on my personal pregnancy experience and general prenatal-care information in the United States. Your testing schedule may differ depending on your medical history, pregnancy, and OB practice.
Early Pregnancy Blood and Urine Tests
At one of your first prenatal appointments, your provider will usually order a group of blood and urine tests.
The initial prenatal bloodwork may include:
- Blood type and Rh factor
- Complete blood count, or CBC
- Antibody screening
- Testing for anemia
- Rubella immunity
- Hepatitis B and hepatitis C screening
- HIV and syphilis screening
- Testing for certain other infections
A urine sample may also be collected to check for a urinary tract infection and to look for glucose, blood, or protein in the urine.
These are usually routine tests and generally do not require fasting unless your provider is ordering additional bloodwork that does.
hCG Blood Tests in Early Pregnancy
Human chorionic gonadotropin, or hCG, is the hormone detected by pregnancy tests.
In very early pregnancy, a provider may order quantitative hCG blood tests approximately 48 hours apart to see how the level is changing. This is often casually described as checking whether the hCG is “doubling.”
However, hCG does not have to double perfectly every 48 hours for a pregnancy to be healthy. The expected rate of increase can vary based on the starting level and how far along the pregnancy is.
Serial hCG testing is not required for every pregnancy. It is more commonly ordered when:
- It is too early to see the pregnancy clearly on an ultrasound
- There is bleeding or significant pelvic pain
- The pregnancy location is uncertain
- There is concern about an ectopic pregnancy or miscarriage
- The patient has a history that warrants closer monitoring
A single hCG result cannot show whether a pregnancy is progressing normally. Providers consider the pattern of change together with symptoms, gestational age, and ultrasound findings.
Thyroid Testing
Thyroid function may be checked with a TSH blood test and, when appropriate, a free T4 test.
Not every pregnant patient receives the same thyroid testing. It may be especially important if you have:
- A history of thyroid disease
- Symptoms of thyroid dysfunction
- An autoimmune condition
- A family history of thyroid disease
- A history of infertility or pregnancy loss
- Previous thyroid surgery or treatment
- Other medical risk factors
If you already take thyroid medication, your levels may be checked several times during pregnancy because your dosage may need to be adjusted.
No special preparation is usually necessary for thyroid bloodwork, but tell your provider about any medications and supplements you take.
Baseline Urine Protein Testing
Protein in the urine is one of the findings providers evaluate when they are concerned about preeclampsia. However, protein in a single urine sample does not automatically mean someone has preeclampsia.
Some patients have a baseline urine protein test early in pregnancy. This provides a starting point that can be compared with later results if blood pressure or other concerns develop.
Baseline testing may be more likely for patients with:
- Chronic hypertension
- Kidney disease
- Diabetes
- A previous history of preeclampsia
- Other risk factors requiring closer monitoring
The test may involve:
- A urine dipstick
- A protein-to-creatinine ratio from one urine sample
- A 24-hour urine collection
I also had urine protein testing during early pregnancy. Because I was considered high-risk and received additional monitoring, this may not be part of every patient’s routine first-trimester testing.
Carrier Screening
Carrier screening looks for genes associated with inherited conditions that parents could pass to their children.
Depending on your history and the screening panel, it may include conditions such as:
- Cystic fibrosis
- Spinal muscular atrophy
- Hemoglobin disorders
- Fragile X syndrome in certain circumstances
- Additional inherited conditions included in expanded panels
Carrier screening is different from NIPT.
Carrier screening examines the parents’ genes. NIPT analyzes cell-free DNA from the pregnancy to estimate the chance of certain chromosome conditions.
If one parent is found to be a carrier, the other parent may be offered testing to determine whether the pregnancy could be at increased risk.
NIPT: Noninvasive Prenatal Testing
NIPT stands for noninvasive prenatal testing. It is also called cell-free DNA screening, or cfDNA screening.
It can generally be performed beginning at about 10 weeks of pregnancy. It requires a regular blood draw from the pregnant patient and usually does not require fasting.
The test analyzes small fragments of placental DNA circulating in the maternal bloodstream. It commonly screens for the chance of:
- Trisomy 21, or Down syndrome
- Trisomy 18
- Trisomy 13
- Certain sex-chromosome conditions, depending on the test
Results often take approximately one to two weeks, although timing varies by laboratory.
Finding Out the Baby’s Sex Through NIPT
NIPT may also reveal the baby’s likely sex well before the anatomy scan.
The test looks for sex-chromosome information in the cell-free DNA. When Y-chromosome material is detected, the result usually indicates a male fetus. When it is not detected, the result usually indicates a female fetus.
Because the blood test can be performed at about 10 weeks, many parents receive the result and learn the baby’s sex around 11 or 12 weeks.
That was how I learned that I was having a girl. We knew from the NIPT blood test before the baby’s sex could be clearly seen on an ultrasound.
NIPT is highly accurate for fetal sex, but it should not be described as 100 percent guaranteed. Rare discrepancies can occur because of low fetal fraction, a vanishing twin, chromosome differences, or laboratory and sample issues.
You can also choose not to receive the sex information. If you are planning a surprise or gender reveal, tell your provider and be careful when opening the laboratory report—the result may be displayed very clearly.
What if NIPT does not produce a result?
Occasionally, a laboratory cannot report a result because there is not enough fetal fraction in the blood sample. This can happen for several reasons and does not automatically mean that something is wrong.
Your provider may recommend:
- Repeating the blood test
- Meeting with a genetic counselor
- Having a detailed ultrasound
- Discussing diagnostic testing
NIPT is an advanced and highly accurate screening test, but it is not a diagnostic test. A high-risk result does not confirm that the baby has a chromosome condition. Diagnostic testing such as chorionic villus sampling, or CVS, or amniocentesis may be offered for a more definitive answer.
NT Scan: Nuchal Translucency Ultrasound
The nuchal translucency scan, commonly called the NT scan, is usually performed between approximately 11 weeks and 13 weeks 6 days.
During the ultrasound, the sonographer measures the fluid-filled space at the back of the baby’s neck. The examination may also look at early fetal development and certain visible structures.
An increased NT measurement does not provide a diagnosis by itself. It may be associated with a higher chance of chromosome conditions, heart problems, or other structural differences, so additional evaluation may be recommended.
What the appointment is like
The scan is usually performed over the abdomen, although a transvaginal ultrasound may occasionally be needed to obtain clearer images.
The baby must be in a specific position for the sonographer to obtain an accurate measurement. If the baby is facing the wrong direction, you may be asked to:
- Turn onto your side
- Cough
- Walk around for a few minutes
- Empty or refill your bladder
- Wait for the baby to move
The appointment may therefore take longer than expected. Difficulty obtaining the measurement does not necessarily mean that anything is wrong—the baby may simply be uncooperative that day.
Second-Trimester AFP Blood Test
During the second trimester, your provider may offer a maternal serum alpha-fetoprotein test, commonly called the AFP test.
It is usually performed between approximately 15 and 22 weeks, although individual practices may prefer a narrower window.
AFP screening primarily estimates the chance of open neural tube defects, such as spina bifida. This is important because NIPT and AFP screening look for different conditions. A normal NIPT result does not replace neural tube defect screening.
The AFP test requires a routine blood draw and usually does not require fasting.
An elevated AFP result does not necessarily mean that the baby has a condition. Results can be affected by:
- Incorrect pregnancy dating
- Multiple pregnancy
- Placental factors
- Maternal characteristics
- Other pregnancy-related circumstances
If the result is outside the expected range, your provider may review the pregnancy dates, order a detailed ultrasound, or discuss additional testing.
The 20-Week Anatomy Scan
The anatomy scan is usually performed between 18 and 22 weeks. It is one of the longest and most detailed ultrasounds of pregnancy.
During the examination, the sonographer may evaluate:
- Brain and skull
- Face and lips
- Spine
- Four chambers of the heart
- Stomach and abdominal wall
- Kidneys and bladder
- Arms, legs, hands, and feet
- Umbilical cord
- Placenta location
- Amniotic fluid
- Cervical length
- Overall fetal growth
The baby’s sex may also be visible, but that is not the medical purpose of the scan.
Should you drink water before the anatomy scan?
This depends on the imaging center.
Some offices ask patients to arrive with a full bladder because it can help with certain views, including the cervix and placenta. Other offices do not require it.
Follow the instructions from your own ultrasound center. If they request a full bladder, ask how much water to drink and when to begin drinking it. There is no need to make yourself excessively uncomfortable by guessing.
How long does the anatomy scan take?
The scan often takes about 30 to 60 minutes, but it can take longer.
A major factor is the baby’s position. If the baby is curled up, facing the wrong direction, covering the face, or not providing a clear view of the heart or spine, the sonographer may need more time.
You might be asked to change positions, walk around, use the restroom, or return on another day.
Being asked to come back for additional images does not automatically mean that a problem was found. Sometimes the baby simply did not cooperate enough for the sonographer to obtain every required view.
Fetal Echocardiogram
A fetal echocardiogram is a detailed ultrasound focused specifically on the baby’s heart. It is often performed during the second trimester, commonly around 18 to 22 weeks, although the timing may vary.
The examination looks more closely at:
- The four chambers of the heart
- Heart valves
- Major blood vessels
- Blood-flow patterns
- Heart rhythm
- The heart’s development and function
A fetal echocardiogram may be recommended because of:
- A suspected finding on the anatomy scan
- Certain maternal medical conditions
- A family history of congenital heart disease
- Some medication exposures
- An increased NT measurement
- Certain genetic or chromosome findings
- Other pregnancy-specific risk factors
I had a fetal echocardiogram during my pregnancy as part of my additional monitoring. The appointment felt similar to the anatomy scan, but much more time was spent obtaining detailed views of the baby’s heart.
Like the anatomy scan, it may take longer if the baby is not in a helpful position. An incomplete view does not necessarily mean there is a heart problem. Sometimes another appointment is needed simply to finish taking the required images.
What I Learned From These Appointments
Before each prenatal test or ultrasound, confirm:
- Whether you need to fast
- Whether you should arrive with a full bladder
- How long the appointment may take
- Whether the test is performed at the OB office, a laboratory, or an MFM center
- Whether you need a referral or insurance authorization
- Whether children or additional visitors are allowed
I also learned that a follow-up appointment does not always mean something is wrong.
Sometimes a screening result needs to be clarified with another test. Sometimes the blood sample does not contain enough fetal DNA. And sometimes the baby simply refuses to turn around for the ultrasound.
Understanding whether a test is a screening test or a diagnostic test can make the process feel much less frightening.
Recommended Reading
(Disclosure: As an Amazon Associate, I may earn from qualifying purchases at no additional cost to you. I only recommend books, products, and resources that I have personally used, read, or genuinely believe may be helpful to my readers. Thank you for supporting Stateside Edit.)
A Simple Way to Organize Your Ultrasound Photos
By the time I reached the anatomy scan, I had collected ultrasound photos from several different appointments. An ultrasound photo album gave me one place to keep them in chronological order, along with the date and gestational week of each scan.
Because ultrasound printouts may fade over time, it is also a good idea to scan or photograph each image and save a digital copy. If you are choosing an album, look for acid-free, archival-quality pages designed to protect photos.
I found this (click here)👉ultrasound photo album helpful for keeping each scan together from the first trimester through the anatomy scan.
As an Amazon Associate, I earn from qualifying purchases.
Related Reading
When Is Your First Prenatal Appointment in the U.S.?
My Honest Experience Using an At-Home Fetal Doppler
What I Tell My Patients Before They Start Trying to Conceive
First Trimester Symptoms: What's Normal in Early Pregnancy? What I Experienced (and What I Wish Someone Had Told Me)
Second Trimester of Pregnancy: Feeling Better, Baby Kicks, and an Unexpected Illness
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