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Pregnancy tests have come a long way. Historically, women didn’t have a reliable method of knowing if they were pregnant without going to the doctor. It wasn’t until the first at-home pregnancy test was invented in 1976 that women could confirm that they were expecting.
But despite technological advances that let women know they are pregnant, there’s still a lot of mystery about a woman’s menstrual cycle.
A woman may have a delayed or missed period, but still have a negative pregnancy test. In those situations, she has to wonder what’s going on. Is she pregnant? Is something wrong?
Here are a few reasons your period may be late, even if your pregnancy test is negative.
If you’re trying to get pregnant, there’s good news: You may still be pregnant. Sometimes, levels of the pregnancy hormone human chorionic gonadotropin (hCG) early in pregnancy aren’t yet high enough for a home pregnancy test to detect.
One study found that home pregnancy tests only have to detect hCG levels above 25 milli-international units per milliliter (mIU/mL) to achieve the commonly advertised 99 percent accuracy rate. The writers of a 1991 study calculated that to detect 95 percent of pregnancies, a test would have to detect levels as low as 12.4 mIU/mL. But not all home pregnancy tests were consistently sensitive enough to do so.
A woman’s cycle can vary widely, so if you conceived later in your cycle, your hormone levels may not be high enough at the time of your missed period.
There can be as much as a 13-day difference in when ovulation occurs, meaning that you may think you are 4 weeks pregnant when you’re only two weeks along. Pregnancy bleeding, recent hormonal contraceptive use, or breastfeeding can all interfere with accurately knowing your dates, as well.
If you think you may be pregnant after a missed period but got a negative result on your pregnancy test, wait a few days. Then retest. If you continue to miss your period, be sure to talk to your doctor to rule out any complications.
Several outside factors can wreak havoc on your menstrual cycle. Stress, for example, can delay your period. Malnutrition can affect it, too. Your cycle can fluctuate if you drink too much caffeine or don’t eat enough food.
Sudden lifestyle changes, such as intense exercise or working the overnight shift on your job, can also cause your period to be irregular.
Breastfeeding can cause some irregularities in your cycle. Even after your baby arrives and your period returns, it may take some time before your cycle goes back to normal.
Breastfeeding is also unpredictable month to month. As babies grow, their feedings may change. For example, if your baby goes through a growth spurt and suddenly increases the frequency of night feedings, it may interfere with your cycle.
Read more: Why women get irregular periods while breastfeeding »
Medical conditions such as polycystic ovary syndrome (PCOS) or thyroid problems may cause women to have highly irregular cycles and missed periods. Some women may have very light periods, some may have very heavy periods, and some may skip periods altogether.
Menopause for women typically begins around age 50. In some women, however, it can start prematurely, before the age of 40. It’s different for everyone. If you have missed your period for over 90 days and are not pregnant, talk to your doctor about getting tested for any underlying medical conditions.
Birth control may cause irregularities in your cycle. Other types of medications may lead to a missed period, as well. For example, blood pressure drugs or allergy medications can throw off your cycle.
There may be many different reasons for a negative pregnancy test after a missed period. You may be dealing with an undiagnosed medical condition, such as polycystic ovary syndrome, or it could be a lifestyle issue, such as extreme stress. After getting a negative test result, you should wait a few days to a week before taking another test. If you test negative a second time and still haven’t had your period, make plans to see your doctor immediately.
For many people trying to conceive, taking multiple early pregnancy tests becomes a habit. However, taking them before your period is expected is not recommended because even if you are pregnant the test may not produce an accurate result. Instead, it's best to wait until at least 14 days past ovulation (DPO) before doing a pregnancy test. This is typically when enough hCG hormone would be circulating in your body for a positive reading, Holding off to 15 DPO is even better.
Whether you are hoping for a positive result or are not trying to conceive and anxious to know ASAP if you're pregnant, there are many good reasons not to take tests early (“early" meaning before your period is actually due, although technically, a pregnancy test taken on the day your period is due is also considered early). The good news is that once you wait until 14 or 15 DPO, test accuracy is extremely high. So, before you take that next test early, consider these drawbacks.
Disappointment
If you're hoping to conceive and your early test is negative, you’re likely to be disappointed. The odds of getting a positive result at 10 DPO are extremely small, even if you did actually conceive. Every day earlier than that, those odds are even lower.
What about early pregnancy tests—the ones where the box says you can take the test before your missed period? If taken correctly, these may deliver a positive result a day or two before your period is expected (say, at 12 DPO, not 10). But an early negative may be false. That means waiting another few days and re-testing. Consider whether that is worth your money and your emotional well-being.
Unclear Results
An early test doesn’t really answer any questions. It just confirms you don’t have any detectable pregnancy hormone in your urine yet. The process of fertilization and implantation takes several days, and a test taken before this process is complete won't be positive even if you're pregnant.
Chemical Pregnancy
If you do get an early positive pregnancy test result, it's not time to relax and celebrate (if you want to be pregnant) or panic (if you don't want to be pregnant). Unfortunately, one of the biggest drawbacks of early testing is that these early tests can detect a pregnancy that isn’t going to last, known as a chemical pregnancy.
According to at least one study, very early miscarriages may occur up to 30% of the time. Some are so early that most people don’t realize they are having one. If you don't test, you will get your period without knowing that you had conceived a nonviable pregnancy. While it may be disappointing to get your period, this may be less painful than thinking you were pregnant and then experiencing a loss.
You should not consider a positive to be a true positive until it happens at 15 or 16 DPO (in other words, after your period is late). Of course, there is still a risk of miscarriage at this point but it's lower than at 10 DPO.
Anxiety
The two-week wait can be a stressful, anxious time, born out of the uncertainty between ovulation and your expected period. You may think that taking tests makes it less intense, but it really doesn’t. You just won’t know if you're pregnant until your period is late and then you take a test.
Taken too early, a test—whether it's negative or positive—will not give you a clear answer. And that uncertainty is likely to do nothing to ease your anxiety during this time.
Effect of Fertility Treatments
If you’re going through fertility treatments, an early pregnancy test may pick up on the hormones used in these treatments. Specifically, if you have a trigger shot—or an injection of hCG, sold under the brand names Ovidrel, Novarel, Pregnyl, and Profasi—you’re injecting pregnancy hormone into your system.
This means that if you took a pregnancy test the day after the injection, you would get a positive result. But that doesn’t mean you’re pregnant. Wait at least 10 days after the injection to test (12 days is even better).
Cost
Even the ultra-cheap pregnancy test strips that you buy in bulk can add up if you take multiple tests per month (which you'll need to do if you test too early). If you're trying to conceive for several months or more, you'll use a lot of tests. Since you can't get a definitive answer on a too-early test, save them for when they're more likely to be accurate.
A Word From Verywell
Taking an early pregnancy test is certainly tempting if you are trying to conceive. Tests promising an early result are readily available, as are very inexpensive options that might allow you to take multiple tests with every cycle. But the uncertainty of early testing may produce more stress than waiting, even when waiting feels like an eternity. If that's the case for you, hold off until you miss your period.
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Gnoth C, Johnson S. Strips of hope: Accuracy of home pregnancy tests and new developments. Geburtshilfe Frauenheilkd. 2014;74(7):661-669. doi.org:10.1055/s-0034-1368589
Cleveland Clinic. Your guide to pregnancy tests.
Han S. The chemical pregnancy: Technology, mothering, and the making of a reproductive experience. J Motherhood Initiative. 2014;5(2):42-53.
Larsen EC, Christiansen OB, Kolte AM, Macklon N. New insights into mechanisms behind miscarriage. BMC Med. 2013;11(1):154. doi:10.1186/1741-7015-11-154
U.S. Food and Drug Administration. Pregnancy.
Annan JJ, Gudi A, Bhide P, Shah A, Homburg R. Biochemical pregnancy during assisted conception: A little bit pregnant. J Clin Med Res. 2013;5(4):269-274. doi:10.4021/jocmr1008w
By
Rachel Gurevich, RN
Rachel Gurevich is a fertility advocate, author, and recipient of The Hope Award for Achievement, from Resolve: The National Infertility Association. She is a professional member of the Association of Health Care Journalists and has been writing about women’s health since 2001. Rachel uses her own experiences with infertility to write compassionate, practical, and supportive
articles.
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