The short answer: If there is a second line on a pregnancy test, no matter how faint, within 10 minutes of taking the test, the test is positive.
A pregnancy test reacts to HCG (a pregnancy hormone) in urine. HCG levels become higher, the further you are into your pregnancy.
First thing in the morning, urine is more concentrated; after drinking, or later in the day, urine is less concentrated. This means that the levels of HCG in your urine are at their highest first thing in the morning, meaning a stronger reading on a test. A test taken first thing in the morning will usually be darker than a test taken at night.
A faint positive on a pregnancy test is still a positive; it just means that you are earlier in the pregnancy and have lower levels of hormones. A darker line may indicate either that you’re further along in your pregnancy or in rare cases, that it is a multiple pregnancy.
However if you take a pregnancy test and it is negative (no second line), you are not pregnant. If you leave the test and look at it again later (for instance an hour) and a line has appeared, this does not mean you are pregnant. This is called an evaporation line, caused by the test drying. Any result after the first ten minutes is usually incorrect. Do a second test.
Most women ovulate 14 days after the first day of their period. However this is based on the average only. Women have varying cycle lengths and hormone levels, so every woman will ovulate on a different day. There are ways to monitor what day you ovulate using your basal body temperature or the type of cervical mucous you experience.
Generally, it takes 14 days after conception before the hormone levels in your body are strong enough to produce a positive pregnancy test. This means you need to test 14 days or more after ovulation for an accurate result. If you’re still not sure, see a doctor for a blood test.
Susannah is a certified Birth Doula through Childbirth International and the founder of Trimester Talk. With a background in journalism and digital strategy, she combines evidence-based research with real-world knowledge to create accessible content about pregnancy and parenting. She’s a mother of two and stepmother of two more, all of them now teenagers.