A pregnancy test will help determine whether you have conceived. If the test is positive, it means you are pregnant. If negative, you are not pregnant. Pregnancy tests work by identifying human chorionic gonadotropin (hCG), a hormone your body produces when you are pregnant. The levels of hCG indicate how many days or weeks since conception have passed.
How Does a Pregnancy Blood Test Work?
The pregnancy test is conducted on a blood sample detecting a hormone known as Human Chorionic Gonadotropin (hCG). Your body produces this hormone when you conceive and a fertilized egg attaches to your uterus wall.
Timeline: This usually takes place within 6 days after fertilisation. hCG levels increase quickly, doubling every 2 to 3 days post fertilisation.
By detecting the levels of hormone in the blood, you can determine how long has elapsed since you have fallen pregnant.
Types of Pregnancy Tests
There are two main types of pregnancy tests:
🏠 Urine Tests (Home Pregnancy Tests)
Over-the-counter home pregnancy tests are urine tests that can be conducted at home. They only indicate whether hCG is present or not.
🩸 Blood Tests (Beta hCG)
Blood tests are sent to a laboratory for analysis and are much more accurate, providing you with a quantitative result of the hormone level in your blood.
Beta hCG pregnancy test (also known as the quantitative human chorionic gonadotropin test) measures the levels of hCG in a woman's body. A small blood sample is taken from a vein. Unlike urine tests, the Beta hCG test measures the exact amount of hCG present in the blood.
Two Types of Blood Pregnancy Tests
1. Quantitative hCG Test (Beta hCG)
This test calculates the exact amount of hCG present in your blood. Benefits include:
- ✅ Can detect lower levels of hCG
- ✅ Tracks problems during pregnancy
- ✅ Helps detect ectopic pregnancy (when a fertilized egg implants outside the uterus)
- ✅ Monitors hCG levels after miscarriage
2. Qualitative hCG Test
This test simply checks for hCG and tells whether you are or are not pregnant. Key points:
- Doctors usually order these to confirm pregnancy
- Can detect hCG as early as 10 days after conception
- Provides a simple yes/no result
When to Take a Pregnancy Test
You may perform most pregnancy tests from the first day of a missed period.
Important: If you don't know the date of your next period, conduct the test at least 21 days after unprotected sex.
Early Symptoms of Pregnancy
1. 🩸 Cramps and Spotting
When sperm fertilizes an egg, the fertilized egg attaches itself to the uterus wall. One of the earliest signs of pregnancy may be cramping and spotting.
- Cramps are similar to period cramps
- Many women mistake them for the start of their period
- Light bleeding (implantation bleeding) may occur
2. 👙 Change in Breast Size
Breast changes are another early sign of pregnancy. Due to hormone level changes:
- Breasts may become sore, swollen or tingle within 1-2 weeks
- They may feel tender to touch
- May appear fuller or heavier
- The areola (area around nipples) may become darker
3. 💧 Early Pregnancy Discharge
You may notice milky, white discharge from your vagina. This is related to the thickening of the vagina walls which begins shortly after fertilization.
4. 📅 Missed Period
The most well-known symptom of pregnancy is a missed period. However, not all missed periods are due to pregnancy. Other causes include:
- Significant weight gain or loss
- Hormonal issues
- Stress or fatigue
- Stopping birth control pills
If your period is late and there's a chance of conceiving, you should take a pregnancy test.
5. 🤢 Morning Sickness
Morning sickness (nausea) is a common symptom, though not experienced by every pregnant woman. Key facts:
- Can occur at any time of day
- Most common in the morning
- Caused by pregnancy hormones
- Usually improves after the first trimester
6. 😴 Fatigue
Feeling unusually tired is normal during pregnancy. You may feel fatigued within a week after fertilisation. This is usually related to:
- Higher levels of progesterone
- Lower blood sugar
- Lower blood pressure
- Increased blood production
Tip: Eat foods rich in protein and iron to help offset tiredness.
Other Pregnancy Symptoms
Pregnancy produces several changes in hormonal balance, which can lead to:
- 🚽 Frequent urination — often starts around week 6-8
- 💩 Constipation — progesterone slows digestion
- 🤕 Back pain and headaches — common throughout pregnancy
- 🤧 Nasal congestion — due to increased blood and hormone levels
- 🎈 Bloating — similar to period bloating
- 😢 Mood swings — common in the first trimester
- 💫 Fainting and dizziness — related to blood pressure changes
Will Every Woman Experience These Symptoms?
As every woman is different, their experience during pregnancy will vary. Since early pregnancy symptoms often mimic period symptoms, you may not immediately know you have conceived.
What to Do After a Positive Pregnancy Test
It's important to confirm pregnancy quickly after conception so you can:
- ✅ Start accessing prenatal care
- ✅ Make necessary lifestyle changes
- ✅ Begin taking prenatal vitamins
- ✅ Schedule your first antenatal appointment
Key Takeaways
The definitive way to know whether you are pregnant is to undergo a pregnancy blood test, which detects the hCG hormone. The test is quantitative, so the levels of hCG will tell you how many days or weeks since conception have passed.
While there are many early symptoms of pregnancy — including missed periods, cramps, spotting, breast changes, and morning sickness — the only way to know for sure that you are pregnant is to undergo a blood test.
🤰 Book Your Pregnancy Test at Walk In Clinic London
Our private blood tests provide accurate, quantitative results so you know exactly where you stand. Results are typically available within 24-48 hours.
We also offer comprehensive Well Woman health screenings for complete peace of mind.