Causes & Treatment

Which prenatal tests, when & why?

Eloise Edington  |   4 Jan 2023


US prenatal testing schedule 2023

From pre-pregnancy to third trimester, most moms-to-be will work through a similar prenatal testing schedule with their care team. Keep reading for the up-to-date guide to what to expect, and early, more advanced, testing options to ask your doctor about.

Are there any new/earlier tests I should know about?

When running through your prenatal testing schedule, your care team will discuss the usual checks, like diabetes screening and tests for Group B Strep. Depending on your history and situation, you may also book in for an extra screening, earlier test or less-standard procedure. This can be nerve-wracking, especially if you’ve been on a fertility journey already, and are perhaps more aware of every milestone, and testing window.

It helps to be completely clear on the journey ahead. Plus, understanding your options for the earliest, most accurate and safest prenatal testing. Bookmark the prenatal testing schedule below, and make a note to look into the safest, most break-through options with your care team, including the Luna Prenatal Test, available from 8 weeks of pregnancy, from Luna Genetics.

In terms of a prenatal testing schedule ACOG (The American College of Obstetricians and Gynecologists) have published a standard chart, which we’ve updated with a few advanced options for earlier, more accurate (and completely safe) testing, plus a few tests more specific to IVF or fertility treatment.

Prenatal-testing-Luna-Genetics-pregnancy-test-result

Pre-pregnancy testing

More specific to people who’ve undergone IVF or fertility treatment, or who have a history making certain hereditary conditions more likely, pre-pregnancy testing involves carrier and PGT screening.

Carrier testing

Often done before conception, carrier testing involves specific blood tests to provide information on whether you and your partner, or donor, may carry a hereditary disease.

  • Why? Tests for hereditary conditions and diseases, such as Cystic Fibrosis or Tay
    Sachs, etc
  • How? Blood test
  • When? Can be performed at any time, but often pre-conception, depending on history
  • Any risks? None

PGT (IVF patients)

Also referred to as preimplantation genetic screening, PGS or PGT-A, this test involves embryo testing, for chromosomal abnormalities. It is different to carrier testing, and doesn’t check for specific genetic diseases.

  • Why? Tests for chromosomal abnormalities during the IVF process
  • How? Lab-based embryo testing
  • When? During IVF, often recommended for women aged 37+ and depending on history
  • Any risks? Occasional damage to the embryo
Prenatal-testing-Luna-Genetics-lab-testing

What tests are done in the 1st trimester?

Roughly weeks 0-13 of pregnancy, your first trimester is a period of rapid growth and fetal development.

Here’s what to expect from your prenatal testing schedule, depending on your situation:

Testing for infectious diseases

During your first trimester, you’ll be offered tests as standard for specific infectious diseases. This testing is widely recommended for almost every pregnancy.

  • Why? Tests for infectious diseases, such as Hepatitis B, HIV, Syphilis, etc
  • How? Blood test
  • When? Ideally by 10-12 weeks
  • Any risks? None

Anemia test

Anemia can be common in pregnancy, and comes with symptoms like tiredness, low energy, shortness of breath, heart palpitations and more. Screening is standard, and can help head off further problems as your pregnancy progresses.

  • Why? Prevents associated complications
  • How? Blood test
  • When? Throughout pregnancy, depending on your status
  • Any risks? None

Blood type/Rh factor tests

Confirming blood types allows your care team to diagnose a condition known as Rhesus disease, which can cause your baby to develop anemia and/or jaundice. In rare cases, the condition can cause more serious complications.

  • Why? Helps to diagnose specific conditions, such as Rhesus disease
  • How? Blood test
  • When? Throughout pregnancy, depending on your status
  • Any risks? None

Pap smear

Pap smears are a routine part of your prenatal care in the US, and your nurse will often perform one during your first prenatal appointment. A pap smear can help to identify changes in cervical cells which may indicate cervical cancer, or another precancerous condition.

  • Why? Helps to identify risks for specific conditions, such as cervical cancer
  • How? Internal exam
  • When? Throughout pregnancy, depending on your status
  • Any risks? None (occasional light bleeding due to irritation of the cervix)

Ultrasound

Ultrasounds help your care team build a picture of your pregnancy. They can be carried out at any stage of pregnancy, and provide information to pin down your estimated due date, indicate gender and also to help detect specific health conditions, or risks to your baby’s development.

  • Why? Helps to indicate how your pregnancy is developing
  • How? External (abdomen) or internal (vaginal) ultrasound scan
  • When? Throughout pregnancy, depending on your status
  • Any risks? Small risk of internal bleeding (internal ultrasound only)

Luna prenatal genetic test

This cutting-edge test helps to safely detect fetal abnormalities (such as Down Syndrome and trisomy 13/18), with more accuracy, earlier in the pregnancy. The test also detects deletion syndromes better than other noninvasive tests. It’s currently the only noninvasive prenatal genetic test to provide highly accurate results as early as 8 weeks of pregnancy.

Can I go for the Luna Prenatal Test instead of CVS or amniocentesis? Yes. The Luna Prenatal Test provides similar information to CVS or amniocentesis, but is noninvasive (and therefore considered safer) and available much earlier.

  • Why? Detects trisomy and chromosomal deletion syndromes
  • How? Blood test
  • When? From 8 weeks
  • Any risks? None

Interested in the Luna Prenatal Test? It’s available right now through Luna Genetics, or ask your care team if they’re set up to offer it.

Standard NIPT

Traditional noninvasive prenatal testing (NIPT) also helps to determine your baby’s risk of being born with certain genetic abnormalities. It primarily looks for Down Syndrome and trisomy 13/18 – accuracy varies by disorder. It can be done as early as 10 weeks of pregnancy, and is non-diagnostic.

  • Why? Indicates specific chromosomal abnormalities
  • How? Blood test
  • When? From 10-12 weeks
  • Any risks? None

CVS test

Chorionic villus sampling (CVS) may be offered in pregnancy to check if your baby has a genetic or chromosomal condition. It’s non-standard, and involves a small sample of cells being removed from your placenta, for testing.
CVS is classed as invasive, and usually carried out between 10-13 weeks of pregnancy.

  • Why? Diagnoses specific genetic or chromosomal conditions
  • How? Placental testing (removal of placental cells, for testing)
  • When? From 10-13 weeks
  • Any risks? Invasive, with associated risk of miscarriage and infection

Integrated screening part 1

Integrated screening is a two-part test, assessing your baby’s risk of being born with conditions like Down Syndrome, trisomy 13/18, or other specific syndromes or defects, such as spina bifida. The first part is usually carried out between 11-14 weeks of pregnancy.

  • Why? Indicates specific genetic or chromosomal conditions
  • How? Ultrasound and blood test
  • When? From 11-14 weeks
  • Any risks? None
Prenatal-testing-Luna-Genetics-ultrasound

What tests are done in the 2nd trimester?

Roughly weeks 14-26 of pregnancy, your second trimester takes you beyond halfway in your baby’s development, and encompasses some big milestones, like feeling movement for the first time.

Depending on your situation and profile, your care team may also offer the following prenatal testing schedule:

Diabetes test

Diabetes – whether it’s a pre-existing condition or triggered by pregnancy – can increase the chance of complications for you and your baby. Careful management with your doctor and care team reduces the risks, so screening is often part of the prenatal testing schedule.

  • Why? Prevents associated complications, like having a large baby (macrosomia), preeclampsia, premature birth and associated issues with hypoglycemia
  • How? Blood test
  • When? Throughout pregnancy, depending on your status
  • Any risks? None

Preeclampsia tests

Preeclampsia affects some women in pregnancy, usually from around 20 weeks, or soon after delivery. Treatment is very effective, but left undiagnosed preeclampsia can cause serious complications for you and your baby.

  • Why? Indicates and diagnoses preeclampsia, helping to prevent specific associated complications
  • How? Blood pressure, urine sample, blood test and further tests (depending on your care team’s advice)
  • When? Throughout (blood testing from 20 weeks)
  • Any risks? None

Sequential screening follow-up

If you had part 1 of an integrated screening in your first trimester (see above), you’ll have the option to follow up with your care team around now. In this appointment, your doctor will take you through the results from part 1, and discuss next steps.

Amniocentesis test

This genetic test is offered in specific scenarios, for example for women aged 35 or older, following positive or higher-risk results from an earlier test or having a family history or previous pregnancy affected by a certain condition.

It’s classed as invasive and is usually carried out between 15-18 weeks of pregnancy.

  • Why? Diagnoses specific genetic or chromosomal conditions
  • How? Amniotic testing (removal of amniotic fluid, for testing)
  • When? From 15-18 weeks
  • Any risks? Invasive, with associated risk of miscarriage, infection, Rhesus disease and club foot

Triple or Quadruple screening test

This is another option for your genetic testing schedule, and usually offered if you’re more than 14 weeks pregnant when you have your first ultrasound scan. It’s a blood test, non-diagnostic and uses a blood test to measure certain substances which could indicate a risk for certain syndromes and conditions.

  • Why? Indicates specific genetic or chromosomal conditions
  • How? Blood test
  • When? From 15-20 weeks 
  • Any risks? None

Integrated screening part 2

Part two of the sequential screen involves a second blood test, to build on the information provided by your first trimester assessments. Both parts of the screening are optional, but combining them provides greater accuracy.

Plus, part 1 alone can’t effectively test for open neural tube defects, like spina bifida.

The second part is usually carried out between 16-18 weeks of pregnancy. 

  • Why? Indicates specific genetic or chromosomal conditions
  • How? Blood test
  • When? From 16-18 weeks
  • Any risks? None
Luna-Genetics-BFP-after-IVF-12-week-scan.

What tests are done in the 3rd trimester?

Your third trimester usually covers weeks 27-40 (and beyond) of pregnancy. In this final phase, ultrasounds can be more difficult to get right, as there’s less room to get a clear picture, inside your uterus.

Genetic testing is less common at this point, and your care team will be well underway with seeing out a treatment plan built specifically for you and your baby.

A few common tests at this point include further tests for diabetes and other common conditions, plus:

Preeclampsia tests

See above, you may be monitored for preeclampsia from your second trimester onwards, up to and immediately after your baby is born.

Group B Strep screening

Also known as streptococcus, this normally harmless condition often goes unnoticed outside of pregnancy and the postnatal period. However, it can cause complications if passed to your baby and ACOG recommends screening during weeks 36-37 of pregnancy.

If you test positive, you’ll usually receive a course of antibiotics during your labor and delivery.

  • Why? Diagnoses Group B Strep, helping to prevent specific associated complications
  • How? Vaginal/rectal swab sample
  • When? Around weeks 36-37
  • Any risks? None

As things stand in 2023, that wraps up the standard US prenatal testing schedule. Bookmark it for reference and compare notes with your care team – they’ll give you lots more information about what’s involved with each test and screening, and any less-standard options we haven’t covered.

Keen to order the Luna Prenatal Test, or talk through options with your doctor? The Luna Genetics team are ready to help with any enquiry or FAQ, for earlier, safer, more accurate testing. Contact them today.

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