Pregnancy Test
A pregnancy test checks a sample of urine or blood for human chorionic gonadotropin (hCG), a hormone the body starts making after an embryo implants in the uterus. Home tests use urine and give a yes-or-no result. Blood tests done at a clinic can measure the exact amount of hCG. In surrogacy, the fertility clinic’s blood test (called a “beta”) is the official result, usually taken about 9 to 12 days after embryo transfer.
→ Read the full guide: Pregnancy tests after embryo transfer, explained
Pregnancy Tests: How They Work, When to Test, and What Results Mean After Embryo Transfer
What is a pregnancy test?
A pregnancy test checks a sample of urine or blood for human chorionic gonadotropin (hCG), a hormone the body makes only during pregnancy. hCG is produced by cells that later form the placenta, and it starts appearing shortly after an embryo attaches to the wall of the uterus. In early pregnancy, hCG levels rise quickly, roughly doubling every two to three days, which is why a test that’s negative one day can be positive a few days later.
The two main types
| Home (urine) test | Blood test | |
|---|---|---|
| Where | At home, bought over the counter | At a clinic or lab |
| What it tells you | Yes or no (qualitative) | Usually the exact hCG level (quantitative) |
| How sensitive | Most detect around 20–25 mIU/mL of hCG; “early result” tests may detect less | Can detect very low levels; under 5 mIU/mL is generally considered not pregnant |
| Speed | A few minutes | Hours to a day |
| Can it track a pregnancy over time? | Only roughly | Yes, by comparing two or more results |
Home tests use a strip that changes color or shows a line, plus sign, or word when it detects hCG. The FDA notes that home tests and the urine tests used in doctor’s offices are similar in how well they detect hCG.
Blood tests can pick up a pregnancy earlier than urine tests because hCG concentrations are higher in blood. A quantitative blood test (often called a “beta hCG” or just a “beta”) gives a number, so a clinic can check whether the level is rising as expected.
When to take a pregnancy test
In an unassisted pregnancy, the FDA says hCG can usually be detected in urine 12 to 15 days after ovulation in a 28-day cycle. For the most reliable home result, the FDA suggests testing one to two weeks after a missed period. Even on the first day of a missed period, 10 to 20 out of every 100 pregnant women won’t get a positive result yet, often because of irregular cycles or miscounted dates.
After embryo transfer, the timing works differently, because the clinic knows exactly when the embryo was transferred and how old it was:
- Clinic blood test (beta): Many clinics schedule this 9 to 12 days after a blastocyst (day 5) transfer. Follow your own clinic’s schedule.
- Home tests: Results before about 6 or 7 days after transfer are often unreliable. Testing too early can give a negative result even if you’re pregnant.
- Your OB clock: On beta day after a day 5 transfer, you’re about 4 weeks pregnant by the standard way doctors count. See our [Pregnancy] guide for how the three pregnancy clocks work.
What your results mean
Home test results
- Positive: Usually means hCG was detected and you’re pregnant. If you’re in a surrogacy journey, your clinic’s blood test is still the official result.
- Negative: Not necessarily final, especially if you tested early. The FDA advises treating an early negative as tentative and retesting after a few days.
- Faint line: If a second line appears within the time window in the test instructions, even a faint one, the test has usually detected hCG. Lines that show up after that window (“evaporation lines”) don’t count. A faint line that gets darker over several days is generally a good sign.
- No control line: The test didn’t work. Use a new one.
Blood test (beta) results
| hCG level | What it generally means |
|---|---|
| Under 5 mIU/mL | Negative (not pregnant) |
| 5 to 25 mIU/mL | Borderline. Usually repeated in 2 to 3 days. |
| Over 25 mIU/mL | Generally considered positive |
A single number matters less than how it changes. Most clinics repeat the beta about 48 hours later to see whether hCG is rising as expected. Your clinic will tell you what numbers they’re looking for, since ranges vary by lab and by the day of testing.
False positives and false negatives
Common reasons for a false negative
- Testing too early, before hCG has built up
- Diluted urine (testing later in the day or after drinking lots of fluids). The FDA recommends first-morning urine because it has the most hCG.
- Using a less sensitive test
Common reasons for a false positive or misleading positive
- hCG medication. Some fertility protocols use an hCG injection (often called a “trigger shot”). It can stay in the body for up to about 10 to 14 days and cause a positive home test even without a pregnancy. Many medicated frozen embryo transfers for surrogates don’t use hCG at all, but ask your clinic whether your protocol includes any.
- Reading the test too late, after an evaporation line has formed
- Very early pregnancy loss (chemical pregnancy). In this case, the positive result was real, but the pregnancy ended soon after implantation. These early losses are common and usually aren’t caused by anything the surrogate did.
Pregnancy tests in a surrogacy journey
The beta is the result that counts. Your fertility clinic’s blood test confirms the pregnancy and starts the next steps, such as a repeat beta and the first ultrasound. Depending on your contract, it can also affect when certain payments begin.
Don’t change your medications based on a home test. Keep taking your estrogen, progesterone, and any other prescribed medications until your clinic tells you otherwise, whatever a home test says.
Agree on a plan with your intended parents before transfer. Testing at home is a personal choice, and many surrogates and intended parents talk it through in advance. Things to agree on include:
- Whether you’ll test at home before the beta, or wait
- Who hears results first, and how (call, video, in person)
- What happens if a home test and the beta don’t match
Some surrogates love testing early, and some intended parents prefer to hear only the official news. Neither approach is wrong, but agreeing ahead of time avoids hurt feelings.
The two-week wait is hard. Waiting for the beta can be emotional for surrogates as well as intended parents, especially after a previous negative or loss. Support groups and other surrogates going through transfer at the same time (cycle buddies) can help.
Related terms
HPT]· POAS · Beta · BFP · BFN · 2WW · DPT · PUPO]· Pregnancy · Embryo Transfer (ET) · Frozen Embryo Transfer (FET) · Cycle Buddy
Sources
- U.S. Food and Drug Administration. Home Use Tests: Pregnancy. https://www.fda.gov/medical-devices/home-use-tests/pregnancy
- FDA 510(k) summary K033041, ACON Quik-Check II Home Pregnancy Test Strip (example of a 25 mIU/mL detection cutoff). https://www.accessdata.fda.gov/cdrh_docs/pdf3/K033041.pdf
- UF Health. HCG Blood Test – Quantitative. https://ufhealth.org/conditions-and-treatments/hcg-blood-test-quantitative
- Medical Laboratory Observer. Analyzer-interpreted pregnancy tests: the significance of borderline hCG levels in urine specimens. https://www.mlo-online.com/home/article/13007073/analyzer-interpreted-pregnancy-tests-the-significance-of-borderline-hcg-levels-in-urine-specimens
- FertilityIQ. After the Embryo Transfer. https://www.fertilityiq.com/fertilityiq/ivf-in-vitro-fertilization/after-ivf
- ACOG Committee Opinion No. 700: Methods for Estimating the Due Date (for gestational age on beta day). https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/05/methods-for-estimating-the-due-date