There is no single, definitive answer because the needle and thread test is a folk tradition, not a standardized procedure. Different families and cultural traditions handle miscarriages differently when interpreting the results. Some people say the test counts every pregnancy, including losses. Others say it only counts living children. Because there are no official rules, what you hear depends entirely on who taught the person doing the test.
How the Test Works
The needle and thread test (sometimes done with a wedding ring on a string instead) is an old wives’ tale used to predict the sex and number of your children. In the most common version, you place your left hand on a flat surface while someone holds a threaded needle or ring above it. They lower it to rest on your hand, then trace the needle between each finger from pinky to thumb and back again, finally holding it still above the center of your palm.
The needle then supposedly moves on its own. A back-and-forth swing in a straight line is said to mean a boy. A circular motion is said to mean a girl. Once the movement is noted, the person rests the needle on your hand again and repeats the tracing process. If it swings again, that represents your next child. The test is considered “done” when the needle stays completely still after a reset, meaning no more children.
Where Miscarriages Fit In
This is where things get inconsistent, because folklore doesn’t come with a rulebook. In practice, people tend to fall into three camps:
- The test counts all pregnancies. In this interpretation, every swing of the needle represents a conception, whether that pregnancy resulted in a live birth or not. People who subscribe to this version often say a miscarriage would show up in the sequence in its correct chronological order.
- The test only counts living children. Others believe the needle only moves for babies that were or will be born alive. Under this interpretation, a miscarriage wouldn’t register at all.
- Miscarriages show a distinct movement. A smaller number of people claim that a pregnancy loss shows up as a hesitation, a very small or wobbly swing, or a brief movement that quickly stops, as opposed to the strong, clear motion associated with a live birth.
If you’ve already had children and a miscarriage, you can see how these different interpretations lead to very different readings of the same test. Someone with one living child and one prior loss might see two swings and interpret that as “it counted the miscarriage” or “it’s predicting a future baby,” depending on which version of the tradition they follow.
Why the Needle Moves at All
The movement of the needle or ring isn’t caused by anything mystical. It’s driven by something called the ideomotor effect: tiny, unconscious muscle movements in the hand of the person holding the string. Your body makes micro-adjustments without you realizing it, and those small movements are amplified by the length of the thread, causing the needle to swing in patterns that look deliberate. This is the same phenomenon behind Ouija boards and dowsing rods.
Because the movement originates from the person holding the string, their expectations play a significant role. If someone already knows your pregnancy history and is anticipating a certain number of swings, their hand is more likely to produce that result unconsciously. This also explains why the test can give different results when repeated or when a different person holds the string.
Why Results Seem Accurate Sometimes
People often report that the test “got it right” for their existing children, which feels convincing. But the math works in the test’s favor. With only two possible outcomes per swing (boy or girl), there’s a 50% chance of getting each child’s sex correct by pure chance. For someone with two children, there’s a 25% chance the test nails both in order. That’s not a tiny probability, and among the many people who try the test, a significant number will get accurate-looking results purely by coincidence.
Confirmation bias also plays a role. If the test gets your first two children right but misses the third, you’re more likely to remember the hits and explain away the miss, perhaps by deciding that third swing “must have been” a miscarriage you didn’t know about, or a future pregnancy yet to come.
The Emotional Side of Testing After Loss
If you’ve experienced a miscarriage, doing this test can stir up complicated feelings. Seeing an “extra” swing might feel like acknowledgment of a pregnancy you lost, which some people find comforting. On the other hand, if the test doesn’t seem to register a loss, that absence can feel dismissive. It’s worth keeping in mind that the test has no ability to detect past or future pregnancies. Whatever meaning the results carry is meaning you bring to them, not information the needle is revealing.
The test is best treated as a lighthearted party game rather than a source of real information about your reproductive history or future. It has a roughly 50/50 accuracy rate for sex prediction, which is identical to flipping a coin. No version of the test, whether it uses a needle, a wedding ring, or a strand of hair, has any scientific basis for predicting gender, number of children, or pregnancy outcomes.