How early can a blood test detect pregnancy?

A blood test can detect hCG as early as 7–12 days after conception, before a missed period. Quantitative hCG tests measure exact hormone levels.

Is NIPT covered by insurance in 2026?

Most US insurance plans cover NIPT for women over 35 or those with risk factors. Many plans now cover it for all pregnancies. Check with your provider for specific coverage.

Do I need to fast before a pregnancy blood test?

Fasting is only required for the glucose tolerance test. For routine CBC, NIPT, or quad screen, no fasting is needed.

What Blood Test to Be Done for Pregnancy: A Complete Guide

Discover which blood tests are essential during pregnancy today. From NIPT to glucose screening, our guide covers timing, purpose, and accuracy.

When you confirm a pregnancy, one of the first medical steps is understanding what blood test to be done for pregnancy. These tests go far beyond the simple hCG confirmation—they screen for genetic conditions, maternal health markers, and fetal development risks. At prenatalscreenings.com, we provide evidence-based information to help you make informed decisions about your prenatal care today.

Why Blood Tests Are Essential in Prenatal Care

Blood tests during pregnancy serve multiple purposes: confirming the pregnancy, estimating gestational age, screening for chromosomal abnormalities, and monitoring maternal health. Unlike urine tests, blood tests can detect hCG as early as 7–12 days after conception and provide quantitative results. Today, advancements in cell-free DNA analysis and expanded carrier screening have made blood tests more comprehensive than ever.

First-Trimester Blood Tests (Weeks 8–13)

Complete Blood Count (CBC)

A CBC checks for anemia, infection, and platelet levels. Low hemoglobin may indicate iron deficiency, which affects about 1 in 5 pregnant women in the US. Early detection allows for supplementation before symptoms worsen.

Blood Type and Rh Factor

Determining your ABO blood group and Rh status is critical. If you are Rh-negative and your baby is Rh-positive, your body may produce antibodies that harm future pregnancies. An Rh immunoglobulin shot (RhoGAM) at 28 weeks prevents this.

NIPT (Noninvasive Prenatal Testing)

NIPT analyzes cell-free fetal DNA in your blood to screen for trisomies 21, 18, and 13, as well as sex chromosome conditions. Today, NIPT accuracy for Down syndrome exceeds 99%, with a false-positive rate below 0.1%. This test is typically offered to all pregnant women, regardless of age.

Timing: Optimal between 10 and 13 weeks gestation.
Results: Usually available within 7–10 business days.
Coverage: Most US insurance plans cover NIPT for high-risk pregnancies; check your policy.

Second-Trimester Blood Tests (Weeks 15–20)

Quad Screen

This test measures four markers: AFP, hCG, estriol, and inhibin A. It screens for neural tube defects (like spina bifida), Down syndrome, and trisomy 18. Detection rate for open neural tube defects is about 80%.

Glucose Challenge Screening

Between 24 and 28 weeks, you will drink a sugary solution, and blood is drawn one hour later. Elevated glucose levels indicate gestational diabetes, which affects 6–9% of US pregnancies. If the screen is positive, a three-hour glucose tolerance test confirms the diagnosis.

Test	Week	What It Screens	Accuracy
CBC	8–12	Anemia, infection	High
NIPT	10–13	Trisomies 21, 18, 13	>99%
Quad Screen	15–20	Neural tube defects, trisomies	80%
Glucose Challenge	24–28	Gestational diabetes	85%

Third-Trimester Blood Tests (Weeks 28–40)

Rh Antibody Screen

If you are Rh-negative, this test checks whether your immune system has developed antibodies against Rh-positive blood. A negative result means the RhoGAM shot is working.

Group B Strep (GBS) Screening

Though technically a swab, a blood test may be used if you have a fever during labor. GBS bacteria can cause serious infections in newborns. About 25% of pregnant women carry GBS, and antibiotics during delivery prevent transmission.

Complete Blood Count (Repeat)

Another CBC near delivery ensures you are not anemic, which could complicate blood loss during childbirth.

Choosing the Right Test Panel

Many providers now offer integrated screening—combining first-trimester NIPT with second-trimester quad screen for maximum accuracy. Today, expanded carrier screening (testing for cystic fibrosis, spinal muscular atrophy, and dozens of other conditions) is increasingly recommended by ACOG. Discuss your family history and personal preferences with your obstetrician.

Frequently Asked Questions About Pregnancy Blood Tests

At prenatalscreenings.com, we offer a comprehensive prenatal blood test panel that covers NIPT, carrier screening, and glucose testing—all from a single blood draw. Our CLIA-certified lab provides results within days, and our genetic counselors are available to explain every finding. Order your test kit today and take the first step toward a healthy pregnancy.