Are You Pregnant? Pregnancy Tests Can Drinking Too Much Water Cause Low hCG Levels? By Krissi Danielsson Krissi Danielsson Krissi Danielsson, MD is a doctor of family medicine and an advocate for those who have experienced miscarriage. Learn about our editorial process Updated on April 27, 2020 Medically reviewed Verywell Family articles are reviewed by board-certified physicians and family healthcare professionals. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Andrea Chisholm, MD Medically reviewed by Andrea Chisholm, MD Facebook LinkedIn Twitter Andrea Chisolm, MD, is a board-certified OB/GYN who has taught at both Tufts University School of Medicine and Harvard Medical School. She has over 20 years of clinical experience and is currently is in practice at Cody Regional Health in Cody, Wyoming. Learn about our Medical Review Board Print Westend61 / Getty Images Human chorionic gonadotropin (hCG) is a hormone that your body makes during pregnancy. When you take an at-home pregnancy test by urinating on a test strip, that test determines whether your body is producing hCG. If you are, it tells you that you're pregnant. The test can't tell exactly how much hCG your body is making (it's not what scientists would call a "quantitative" test), but your body needs to be producing a certain minimum amount in order for the test to detect it. How Drinking Water Affects Pregnancy Tests Drinking water—or any fluids—can, in fact, affect the results of an at-home urine pregnancy test, especially when taken very early in the pregnancy. When your urine becomes diluted by drinking lots of fluids, the urine concentration of hCG becomes lower. Take a home pregnancy test using first-morning urine that you collect before drinking any fluids. If the level of hCG in the urine becomes so diluted that it's no longer detectable by an at-home urine-based pregnancy test, that test strip may indicate that you're not pregnant when you actually are. This is known as a false-negative test result. To avoid a false negative result, doctors recommend taking at-home pregnancy tests first thing in the morning, before you start chugging fluids. False Negative Pregnancy Tests When hCG Levels Are at Their Highest Your hCG level rises for several weeks, peaking between weeks eight and 11 of pregnancy. It then decreases and levels off for the rest of your pregnancy. Therefore, experiencing the type of "false negative" mix-up mentioned above is likely to happen only very early on in your pregnancy (like during the first week). After that beginning stage, even if your urine is diluted, your hCG level should still be high enough to be detectable by an at-home urine-based pregnancy test. What to Do After a Negative Pregnancy Test If you take an at-home urine-based pregnancy test very soon after trying to conceive and the result is negative, try waiting a few days—or even another week or two. Then take the test again as soon as you wake up in the morning to make sure that the reading was correct. Most at-home urine-based pregnancy test kits come with two strips for this very reason. If you take a urine pregnancy test after you have missed a period and it is still negative, wait a few days and try again. If a second test still indicates that you are not pregnant, but you have not had a period, contact your physician. Are Home Pregnancy Tests Always Accurate? Another option is to ask your doctor if a blood test that will determine whether you're pregnant with more accuracy is appropriate. The fact is, even if an at-home urine-based pregnancy test shows that you are pregnant, your doctor may still want to confirm those results with a blood test. It's called a quantitative hCG blood test because it can measure exactly how much hCG is in your blood. In this case, the amount of water that you drink will not affect the results, as it will not alter the level of hCG in your blood, even very early in pregnancy. Was this page helpful? Thanks for your feedback! Get diet and wellness tips to help your kids stay healthy and happy. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit