Reading, for three in the morning
You cannot hear anything, and it is the middle of the night
A phone that finds nothing has told you about the room, the angle, the position your baby is lying in and the week you are in. It has told you nothing about your baby.
Real audio where no rhythm holds. Watch an engine decline to print a number over it.
Firstsong is not a medical device, it is not a doppler and it does not use ultrasound. It cannot tell you that your baby is well, and an app that finds nothing has not told you that anything is wrong. If you have noticed fewer movements than usual, or any change in the pattern you know, call your midwife or maternity unit now. Do not wait for morning and do not try an app first.
What is actually happening when a phone hears nothing
A fetal heart makes a small, low, wet sound. Almost all of its energy sits below 200 Hz, lower than the lowest note most people can name, and the loudest part of each beat lasts a fraction of a second. Before a microphone gets an opinion, that sound has to get out of your body.
On the way out it crosses amniotic fluid, the wall of your uterus, the tissue between that wall and your skin, then a layer of air. Every one of those boundaries sends part of the sound back inside. What arrives at the phone is not a heartbeat. It is the last few per cent of one.
Then it meets the wrong instrument. An iPhone microphone is built for a human voice, which lives roughly between 300 Hz and 3 kHz, and it runs automatic gain, so when the true signal is faint the phone turns everything up, including the room. That is why a failed listen sounds like a storm rather than like silence. Your baby sits at one end of that chain of weak links. Every other link sits between the two of you.
Why it happens, and when
Some of these will be true all pregnancy. Some will be different in twenty minutes.
- Where your baby is lying. Heart sounds come out best when the back is against the front of your belly. If the back is turned towards your spine, you are listening to a chest pointed away from you and shielded by its own arms and legs.
- An anterior placenta. A placenta on the front wall of your uterus sits between your baby and the microphone as a thick, fluid rich cushion. Not a problem with your pregnancy, a real problem for a phone. The long version.
- The room. A fridge, a fan, a partner breathing, traffic, a phone on a hard table carrying vibration through the wood. The useful signal is faint enough that ordinary noise wins.
- Where you put it, and how. The gap between two ribs of a very small chest is small, and two fingers width across can be the difference between a rhythm and static. A case, a layer of fabric or a hand pressing hard enough to make the skin creak will each kill it on their own.
- The week you are in. Earlier in pregnancy the chest is smaller, the position less settled, and the public evidence anyone can check far thinner outside the third trimester. What changes week by week.
None of that is a reading of your baby. All of it is a reading of the path between you.
Read the middle number again. Even with research sensors taped to the abdomen, in a clinic, roughly one recording in six had no usable rhythm. Nobody in this category prints that number, because it explains your night and sells nothing.
What actually helps
- Wired headphones. Not for comfort. Speaker and microphone are inches apart, so playing belly sound out loud feeds it straight back in and buries what you want to hear.
- Turn the room off. Fan, extractor, television, washing machine. Lie on something soft rather than sitting at a desk.
- Lie down and roll slightly onto one side. Wait a minute first, because moving around leaves your own pulse raised, and your pulse is the loudest thing in there.
- Start where the kicks are, then go lower. Kicks high up usually mean the head and chest are low. The heart is easiest to find below your navel and a little to one side.
- Bare skin, no case, light contact. Firm enough that there is no air gap, gentle enough that nothing creaks.
- Move in small steps and wait. Thirty seconds still, then two fingers width across, then wait again. Sweeping continuously finds nothing anywhere.
- Stop after ten minutes. Past that the odds do not improve and your own heart rate goes up, which makes a faint signal harder to pull out.
And then the part that is hard to write and harder to read. Some nights none of it works, and the honest answer is that today the sound did not come out of your body in a form a telephone could use. That is a real answer, just not the one you went looking for.
When to call your midwife
There is a signal worth acting on tonight and it is not the app. It is movement. You know your baby's pattern better than any device does, and a change in it, especially fewer movements than usual, is what maternity units want to hear about at any hour, as many times as it happens. The NHS guidance on movements is here, and it does not mention apps.
- Call now if there are fewer movements than usual, or the pattern you know has changed.
- Call now if you are not sure, instead of waiting until you are sure.
- Do not spend an hour on a cold drink and lying still to see whether it starts. That hour is the cost of the mistake.
- Do not let a phone talk you out of the call. Finding a rhythm would not have meant everything is fine, and finding nothing does not mean it is not.
The UK charity Kicks Count exists for exactly this and says it in fewer words. No app on your phone, ours included, changes any of it.
How Firstsong handles a night like this
Firstsong is built so this night ends in a sentence, not a number. When nothing holds it says nothing was found today, says plainly that this alone is not information about your baby, and puts the movements advice back in front of you. While you are still moving the phone it shows a clarity meter rather than a rate, so you can see whether you are getting closer or listening to the fridge.
Three public recordings, three verdicts, decided in this tab. Nothing is uploaded.
One email, the day it opens
Firstsong is not on the App Store yet. Leave an address and you get exactly one message when it is, with the price on the first line. No newsletter, no drip, no partner offers. You can reply to that email and a person reads it.
Stored on our own server, never sold, never shared. Your IP is hashed, not kept. Nothing about your pregnancy is asked for or stored.
The bottom line
A phone that finds nothing is reporting on the phone, the room, the angle, the placenta and the position. Not on your baby. The category blurs that difference because an app that says nothing feels broken, and one that shows 142 over static feels like it works.
Silence is neither reassurance nor alarm. It is an absence of information. What you do have tonight is what you have felt, and if that has changed, the phone is not the thing in your hand you should be using.
Common questions
Does finding nothing mean something is wrong?
No. It means the sound did not reach the microphone well enough to be sure of it, for reasons that have nothing to do with how your baby is. On the research recordings we validated against, made with proper sensors and not a phone, roughly one in six had no usable rhythm. Act on movement, not on silence.
It worked yesterday and tonight it will not. Why?
Almost always position. Your baby has turned and the chest now points at your spine instead of your skin. A full bladder, a different surface under you, a fan you did not notice and a case you forgot to remove will all do it too. Nothing about the pregnancy has to change for the sound to stop coming out.
Would a doppler have found it?
Often, yes. A doppler sends ultrasound in and listens to what comes back, so it is not fighting the losses a passive microphone fights. That is a real difference and we will not pretend otherwise. It is also why midwives are uneasy about them at home, and the reason is not the ultrasound. We wrote that up.
How long should I keep trying?
Ten minutes, once, in a quiet room. If you are still going because you are frightened about movements, stop and call instead.
Keep reading
- Is that my heartbeat or the baby's. the other half of this problem, which produces fake numbers, not silence
- Anterior placenta. the commonest physical reason a belly sounds further away
- Week by week, what a phone hears. what changes between the third trimester and everything before it
- Hear the difference. the engine live on three public recordings, one of which contains nothing
Last checked 2026-08-23