It’s so easy these days – you open a box with a stick in it – go to the loo and pee on the indicated end. Minutes later you have a relatively accurate result and you know if you are pregnant or not..
Before the first home pregnancy test was developed in 1976 women had to rely on the early signs and symptoms their body was giving them before having their pregnancy confirmed by a doctor.
For women who have been trying to conceive, taking an early pregnancy test is a big moment. The whole “am I or aren’t I?” question is about to be answered and the emotions tied up with the big reveal cannot be overestimated.
But repeatedly taking tests can get expensive and disappointing if they’re negative again and again.
So when is a realistic time to take an early pregnancy test to both minimise expense and disappointment?
To answer that it’s best to learn how they work and how your body changes in those early days of pregnancy.
Home pregnancy tests detect the presence of the pregnancy hormone hCG (Beta Human Chorionic Gonadotropin), in your urine.
Your body starts to produce hCG when a fertilised egg implants in your uterus and is secreted by the cells which will go on to form your baby's placenta. It can usually be detected in your urine from about 6 to 14 days after fertilisation.
Ideally, women should wait until they’ve missed a period and felt some pregnancy symptoms before testing. Then the early pregnancy test would simply confirm what they already strongly suspect.
But who can wait? Of course women who are trying to get pregnant and are desperate to conceive will want to start testing almost immediately after intercourse!
A really early pregnancy test is very unlikely to be accurate. Assuming intercourse happens at the right time in the menstrual cycle. It can then take sperm up to 12 hours to travel up to the fallopian tube where it can survive for several days.
However, within 24 hours after ovulation the egg will begin to disintegrate and fertilisation will no longer be possible. So timing really is key.
Once the egg is fertilised, it has to travel the rest of the way down the fallopian tube and into the uterus where it will implant in the prepared lining. This implantation usually occurs 6-10 days after ovulation.
Then you have to wait for hormone levels to rise high enough to be detected on a test. When you decide to test, try not to drink too much beforehand, as it could dilute the levels of hCG in your urine.
The earliest that you can test is seven DPO - days past ovulation (our Emma’s Diary India week-by-week pregnancy guide starts at week one). Any sooner and it’s likely the embryo won’t have had time to implant yet. Only a very small number of women will get a positive test at 7 or 8 DPO. It is still very early to test and it also assumes that you are exactly right about which day you ovulated.
More women can get a positive test 9-11 DPO. This is within that “5 days before your missed period” window that most tests state they can show a positive for. But some women will still not show up at this point.
The best early pregnancy test time is 14 DPO, or the day you expect your period. At this point the egg should be nicely nestled in and have started to produce the necessary hormones to turn the test positive. If it has implanted outside the uterus (ectopic pregnancy) then hormone levels might be too low to detect pregnancy.
A few women will not get a positive test until 15-18 DPO, or after they have missed a period. And a very small percentage will not get a positive test until they are two or more weeks late. If you are late and still getting a negative test, you can get advice from your doctor. However, most commonly, stress or other factors may have delayed ovulation and you are not actually late.
If you’re trying for a baby, you can take your temperature all month long. If you note the temperature rise that indicates ovulation has taken place, but it's important to keep taking your temperature. If, after 18 days, your temperature is still high and you haven’t had a period, there’s a very good chance that you are pregnant.
Some pregnancy tests can detect hCG at a lower concentration than others, which means they can tell you're pregnant even when you have only a small amount of hCG in your system.
Read the information that comes in the test box. Concentrations of hCG are reported in milli-International Units (mIU) per millilitre. A test with a sensitivity of 20 mIU/ml will be able to confirm a pregnancy earlier than one that needs a concentration of 50 mIU/ml.
Some tests may recommend that you use the first urine of the day as levels of hCG become more concentrated in your urine overnight.
For many tests you simply have to pee on a test stick. For others you may have to catch your urine in a small cup and dip a testing strip into your sample. Or a dropper may be provided to place a small sample into a testing well.
Some tests show pink or blue lines on the test strip. Others reveal a plus or minus sign or change the colour of your urine sample. Digital tests display the words "pregnant" or "not pregnant" in a window and some give an estimate of how many weeks ago you conceived.
Home pregnancy tests are accurate if you follow the directions. But some are more sensitive and others are easier to use and interpret so if funds allow, it may be worth buying a couple of different ones.
Remember though that if you test too early you may get a false negative result because not enough of the hormone has built up in your system. Wait four or five days before testing again.
False positives, when the test says you're pregnant but you're not are rare but not impossible. Some medicines such as fertility drugs, which contain hCG, may affect the test results.
You don’t need a prescription for a pregnancy test, they are widely available in chemist shops. You can also buy them online.
Home tests are considered very reliable so if your period is late and a home test is positive you can consider yourself pregnant.
In early pregnancy, before a foetal heartbeat can be detected on a scan, or where there is bleeding and there is uncertainty about whether the pregnancy is continuing, a blood test which measures the hCG levels can help: if they are rising sufficiently they can point to a healthy pregnancy.