Pregnancy Test: What It Is, When to Take It, and How It Works

What is a pregnancy test?

A pregnancy test is a simple and reliable method used to determine whether you are pregnant. It works by detecting the presence of human chorionic gonadotropin (hCG) — a hormone produced by the placenta shortly after a fertilised egg attaches to the uterine lining. hCG levels increase rapidly in early pregnancy, making it a key indicator.

Pregnancy tests can be done in two ways: urine tests, which are commonly available over-the-counter, and blood tests, which are usually performed at clinics or hospitals. Both types of tests check for hCG levels to confirm pregnancy.

When can you take a pregnancy test?

If you suspect you might be pregnant, taking a pregnancy test can help confirm it. One of the earliest and most common signs of pregnancy is a missed period, which usually occurs about 14 days after conception. However, some pregnancy tests can detect pregnancy as early as 10 days after conception, depending on the sensitivity of the test.

For the most accurate results, it is recommended to take the test after you miss your period. Testing too early may lead to a false negative result, as your hCG levels might still be too low to detect.

For urine-based pregnancy tests, the best time to test is first thing in the morning, when your urine is most concentrated and hCG levels are highest. However, some highly sensitive tests can provide accurate results at any time of the day.

How do pregnancy tests work?

Pregnancy tests work by detecting the presence of a hormone called human chorionic gonadotropin (hCG) in your body. This hormone is produced shortly after a fertilised egg implants itself in the lining of the uterus, typically within 6–12 days after ovulation. Once implantation occurs, your hCG levels begin to rise rapidly, doubling every two to three days during early pregnancy.

Home pregnancy tests measure hCG in your urine, while blood tests done at a clinic can detect even lower levels of hCG for earlier results. If you take a test too early, your hCG levels may not be high enough yet to be detected, which could lead to a false negative.

The longer you wait after a missed period, the more accurate the test result will be, as higher hCG levels are easier to detect and give a clearer positive result.

Types of pregnancy tests

There are two main types of pregnancy tests: urine tests (commonly done at home) and blood tests (done at a healthcare facility).

At-home pregnancy test

At-home pregnancy tests are a convenient and private way to check for pregnancy using your urine. When used correctly, these tests can be up to 99% accurate. They are widely available at pharmacies, supermarkets, and online.

• To use an at-home pregnancy test:

  • Collect your urine in a clean container.

  • Use the provided dropper or test stick to apply urine to the test strip.

  • Wait for the result — most tests provide an answer within 3 to 5 minutes.

Some tests may involve directly holding the strip in your urine stream. Always read the instructions carefully for the most accurate result.

Blood pregnancy test

A blood test for pregnancy is usually performed in a clinic or hospital. Your healthcare provider will draw a small sample of blood, which is then analysed in a lab to measure your hCG levels.

There are two types of blood tests:

• Qualitative hCG test:

  • Confirms whether or not hCG is present (yes/no).

• Quantitative hCG test (beta hCG):

  • Measures the exact amount of hCG in the blood, which can help track early pregnancy progress or detect potential issues.

Blood tests are more sensitive than urine tests and can detect pregnancy earlier, even before a missed period.

What do pregnancy test results mean?

Both urine and blood tests can confirm whether you are pregnant, but they differ in sensitivity and how results are displayed.

At-home urine pregnancy test results

Most at-home pregnancy tests use a reactive strip to detect hCG in your urine. The results are usually shown in a small display window. Depending on the brand, a positive result may appear as:

• Two vertical lines

• A plus (+) sign

• The word “Pregnant” on digital tests

It’s important to carefully read the instructions included with the test, as result displays may vary by brand. Most tests also have a control window — a symbol or line in this window confirms the test is working properly.

Urine tests can typically detect hCG around 10 days after conception, but accuracy improves if you wait until after your missed period.

Blood test results

Blood tests are more sensitive than urine tests and can detect lower levels of hCG. They can provide accurate results as early as 7 to 10 days after conception. There are two types of blood tests:

• Qualitative hCG test:

  • Simply indicates if you are pregnant.

• Quantitative (beta) hCG test:

  • Measures the exact level of hCG in your blood.

In early pregnancy, hCG levels should double every 48 to 72 hours. Slow-rising or declining levels may suggest a problem, such as a miscarriage or ectopic pregnancy. On the other hand, unusually high levels of hCG could indicate a multiple pregnancy (e.g. twins) or, in rare cases, a molar pregnancy.

If you’ve taken a pregnancy test and want to confirm your results or speak with a healthcare professional, request an appointment with us for a thorough evaluation.

What to do after a positive pregnancy test?

Getting a positive result on your pregnancy test can bring a mix of emotions — excitement, joy, and even uncertainty. Whether your pregnancy was planned or unexpected, it's important to take the right steps early on to support a healthy pregnancy journey.

Start taking prenatal vitamins

Begin taking prenatal vitamins immediately if you haven't already. These supplements are specially formulated for pregnancy and typically include:

• Folic acid: 

  • Crucial in the early weeks to help prevent neural tube defects (serious birth defects of the brain and spine)

• Iron: 

  • Supports increased blood volume and helps prevent anaemia

• Calcium and vitamin D: 

  • Essential for your baby’s bone development

Make sure your prenatal supplement includes at least 400–800 mcg of folic acid daily, especially in the first trimester.

Schedule your first antenatal appointment

Contact your healthcare provider to arrange your first antenatal screening, ideally within the first 6 to 8 weeks of pregnancy. During this visit, your doctor will:

• Confirm the pregnancy through a blood test or ultrasound

• Estimate your due date

• Discuss your medical history and any risk factors

• Offer advice on diet, supplements, and lifestyle adjustments

Early prenatal care is key to monitoring both your health and your baby’s development. To help you choose the most appropriate antenatal tests and care plan, request an appointment with our specialists at Thomson Medical today.

Adopt a healthy lifestyle

A positive pregnancy test is your cue to start or maintain healthy habits:

• Avoid smoking and alcohol consumption, both of which can harm your baby’s growth and development

• Cut back or eliminate caffeine intake (recommended limit: 200 mg per day)

• Focus on a balanced diet rich in whole grains, lean protein, fruits, vegetables, and healthy fats

• Stay hydrated and get regular, moderate exercise (unless advised otherwise by your doctor)

Be mindful of medications and substances

Some medications and over-the-counter products may not be safe during pregnancy. Always check with your doctor before continuing or starting any new medication, herbal remedy, or supplement.

Prepare emotionally and practically

Take time to process your emotions and share the news with your partner or loved ones when you're ready. You may also want to start learning about pregnancy stages, birth planning, antenatal care and support options.

A positive pregnancy test is just the beginning. For advice and further assessment, you can always request an appointment with us to begin your pregnancy journey on the right foot.

Pregnancy test clinic in Singapore

If you think you might be pregnant, visiting a pregnancy test clinic in Singapore can provide clarity and guidance. While home test kits are convenient, clinics offer professional testing and a supportive environment to discuss your next steps.

At the clinic, a healthcare professional may recommend a urine or blood test to check for pregnancy-related hormones. This method can be helpful if you're unsure about a home test result or if you prefer a more personalised approach.

You may consider visiting a clinic if you’ve missed your period or are experiencing early pregnancy symptoms.

At Thomson Medical, we offer a comfortable and discreet setting for pregnancy-related consultations. Request an appointment with us to receive guidance and support for your pregnancy journey.

FAQ

How soon can I take a pregnancy test?

You can test as early as 10 days after conception, but for the most accurate result, wait until after your missed period.

What time should I take a pregnancy test?

For the most accurate result, it's best to take a pregnancy test first thing in the morning, when your urine is most concentrated and hCG levels are highest. This is especially important if you're testing early in your cycle. However, some high-sensitivity tests can still give reliable results at any time of the day.

How many weeks does it take to confirm if you're pregnant?

If you have a regular menstrual cycle, a home pregnancy test can usually detect pregnancy around 4 weeks from the first day of your last period — typically two weeks after ovulation.

What are the 100% signs of pregnancy?

There are no symptoms that can confirm pregnancy with 100% certainty. Common early signs usually would be a missed period, breast tenderness, abdominal cramps, nausea, and increased salivation. Pregnancy can only be confirmed through a pregnancy test or an ultrasound scan.

What is the maximum delay in periods if not pregnant?

For those with regular periods, a delay of up to 7 days can still be considered normal. If your periods are irregular or the delay is longer, it’s best to consult a healthcare provider to rule out other causes.

How can I test for pregnancy at home without a pregnancy test kit?

While natural methods like salt, sugar, toothpaste, soap, or baking soda tests are popular online, they are only 70–80% accurate and not medically reliable.

Instead, look for early signs such as:

• A missed period

• Morning sickness or nausea

• Breast soreness or changes

• Frequent urination

Are there any precautions to take before doing a pregnancy test?

Yes. To ensure accurate results, avoid drinking excessive fluids before the test, as this can dilute your urine and make it harder to detect hCG levels. It’s also best to wait until after your missed period and use your first-morning urine, which contains the highest concentration of hCG. Always read and follow the instructions provided with the test kit for the most reliable outcome.

Is it possible to be pregnant and still get a negative test result?

Yes, although it’s uncommon, it is possible to be pregnant and still receive a false negative result. This can happen if hCG levels are unusually low, if the test is expired or used incorrectly, or if diluted urine affects the accuracy. In such cases, it’s best to repeat the test or consult a healthcare provider for a blood test or ultrasound to confirm pregnancy.

Is a pregnancy test kit 100% accurate?

Not really. While home pregnancy test kits are highly reliable, they are not 100% accurate. Most are around 99% accurate when used correctly and after a missed period. However, factors such as testing too early, diluted urine, expired tests, or improper usage can lead to false negatives or false positives. For confirmation, it's best to consult a healthcare provider for a blood test or ultrasound.

The information provided is intended for general guidance only and should not be considered medical advice. For personalised recommendations and tailored advice, please consult a specialist at Thomson Medical. Request an appointment with Thomson Medical today.