When you’re trying to get pregnant — or really hoping you’re not pregnant — waiting weeks until you can get results from a pregnancy test can feel impossible.
"It's a time of anxiety for people for different reasons," says Dr. Scott Sullivan, an OB-GYN and the director of maternal-fetal medicine at the Medical University of South Carolina.
"People really, really want to be pregnant, or they're afraid that they're pregnant or they have medical problems where it's important to know as soon as possible. There are lots of motivations," he says.
Which is why women in some online pregnancy forums have come up with a hack to get answers earlier. It’s called "tweaking."
They take home pregnancy tests early and post pictures of their (seemingly negative) tests on dedicated threads on sites like Babycenter.
Then other women "tweak" the pictures using photo editing programs, adjusting the contrast and brightness to see if they can enhance a very faint positive line that might be invisible to the naked eye. There's even an app for it.
But does the science make sense?
First, some background on how home pregnancy tests work: Those little sticks detect a hormone called human chorionic gonadotropin (hCG), which is produced when a fertilized egg implants in the uterus.
Today's pregnancy tests are pretty sensitive, rated to detect hCG levels as low as 25 mIU/ml — which women who are pregnant should reach about 10 to 14 days after fertilization, Sullivan says.
Tweaking tries to detect tests taken at even lower levels of hCG, potentially letting women know a week or two weeks sooner than they would if they waited for a missed period and a strong positive test.
But, he adds, "I have to say that while [knowing early] may help anxiety, medically speaking it probably isn't necessary for most people."
Of course, tweaking is fallible and highly subjective.
"We don't really know yet how accurate the tweaking is," Sullivan says. "Of course it could be wrong. It might be that the technology or the tweaking itself might not be right."
All kinds of physical irregularities in tests — from a "dye run" to dried urine — can look like positive lines when edited, and using the wrong enhancement tools in Photoshop can also lead to red herrings.
While most forums warn that tweaks should be followed up with a later test, the practice can still be emotionally charged, especially since many of the most avid users are trying to conceive month after month.
"When you so desperately want to see a line, your mind starts playing tricks on you," says Micah Farmer, a teacher and mom of one in Virginia who has tweaked other women's tests and had her own tests tweaked. "Unfortunately, if you already see a line, tweaking only makes it worse. I like to joke that I can pull a line from any test, so it's always nice to see if anyone else can pull a line as well to confirm the craziness."
And when tweaking does correctly reveal a very new pregnancy, women run the risk of learning about early miscarriages, called chemical pregnancies, Sullivan says.
Chemical pregnancies are very common and usually have no symptoms, so generally you would never know they had happened — unless you're testing for pregnancy early and repeatedly, tweaking and retesting to see the positive lines grow darker.
"I did have a few very early losses that I discovered from tweaking tests," Farmer says. "Unfortunately, if I hadn't been testing early, I likely wouldn't have known that I was pregnant, so testing before your missed period comes with its warnings."
Despite the warnings, tweaking threads are full of users drawn to the hobby and the support it offers in the tough world of ovulation tests, cycle charting, and fertility drugs.
Kathleen Dziadik, a stay-at-home mom in Connecticut who edited many tests as a leader of a Babycenter tweaking group, found out she was days pregnant with her second child when she and other tweakers uncovered an early positive on her test.
Her doctor was surprised when a blood test confirmed it, telling Dziadik she shouldn't have known for two more weeks. Her daughter was born eight months ago.
"I like to tweak for others because it brings them hope," Dziadik says.
"Many women who resort to needing their tests tweaked are having trouble conceiving or have experienced a loss and feel knowing sooner would be better," she says. "It brings joy to me to be the first to say, 'I see a line!'"
But Sullivan offers measured advice for women who receive a BFP (or Big Fat Positive, in the parlance of the forums) from a tweaked test.
"I think all in all, it's relatively harmless," Sullivan says.
But, he adds, "Don't get too anxious either way." The tweak could be wrong, and early losses are possible. (If you know you're in a high-risk category, see your doctor.)
And keep in the mind that you should still retest in about a week, when a normally progressing pregnancy would mean that that faint line would become a solid one.