AmnioSense: Home-Based Water Breaking Alarm System

This week my wife invented nitrazine underwear. Or, at least she thought of the idea.

Photo of the AmnioSense product box, and three photos of a panty liner that has a yellow testing strip inside the liner, pulled out of the liner and placed inside a plastic drying box.
She is a labor and delivery nurse. A fair number of pregnant women near their due date arrive at the hospital thinking their water has broken, or as my wife says, they may have experienced a spontaneous rupture of membranes.

So a nurse will take a nitrazine paper strip and insert it into the vagina to gauge the woman’s pH or acidity range, sometimes with the aid of a speculum (that link is for all my male readers). If the strip changes the correct color, it indicates the presence of amniotic fluid. In other words, her water has broken.

However, there are many false alarms. Pregnant women often experience urinary incontinence or mistake the after effects of recent "intimate contact." If it makes everyone feel better, I’ll add that a common cause of incontinence is the baby kicking your bladder. That’s got to be fun.

I imagine the conversation in the hospital room going something like this:

"My water broke!"
"I’m sorry, no, you peed on yourself."

So, my wife’s idea was for near-term women to wear nitrazine-laced panties that would change color, immediately letting you know whether you should rush to the hospital.

Well, someone else already thought of it. Say hello to AmnioSense by Med-Direct (see the photo located above, yeah, I’m writing in reverse-pyramid format today).

It is a panty liner with a built-in testing strip. There are seven steps to using it, but it boils down to wearing the liner for up to 12 hours. When there is wetness, remove a testing strip that is sandwiched in the liner, put it into a pre-supplied plastic drying box, and check its color 10 minutes later.

Med-Direct is a UK-based company, but will ship to the US if you don’t mind our skyrocketing exchange rate. A 2-pack of AmnioSense is only £8.50 or 7 go for £21.27 before shipping, but as of this writing 1 British pound equals 2 US dollars.

AmnioSense can be bought domestically in a 2-pack from To Be Parents for $26 or 7 for $62 before shipping. I’m curious whether it’s still cheaper to buy it direct from the UK.

Incidentally, I love marketing names. Similar products exist intended for hospitals that often involve a swab and testing paper. They have names such as Amniotest, AmniSure and, my favorite, Amnicator.


7 Responses to “AmnioSense: Home-Based Water Breaking Alarm System”

  1. Stephanie says:

    The Amnicator. Sounds like something Arnold would say.

    October 26th, 2007 at 9:07 am

  2. Marianne O. says:

    Sorry, I really dislike this idea.

    First, there’s the accuracy issue. Nitrazine tests produce false positives (i.e. indicating that membranes have ruptured when they haven’t) when there is contamination with blood or semen, among other things. This happens even when the test is done properly with a swab & speculum. The accuracy can only go down with an external pad. Maybe way down.
    This doesn’t give me a lot of faith in the product website’s claim that the pads will help to reduce the risk of “unnecessary induction.” If anything I expect the opposite: that false positive results will encourage women to ask for induction when they don’t really need it.

    Second, there’s the cost (economic and environmental) of having women wear & discard these pads day after day, “just in case.” Judging by TV and movies, you’d think that labour always starts with a big splash o’ fluid. The reality is that less than 15% of women experience rupture of membranes before labour. I can sort-of understand putting on one of these pads once rupture is suspected (though the accuracy issue is still big, for me). But wearing one all the time, on the off-chance that the unlikely will happen… and generating costs and garbage along the way? Nope.

    If we’re going to be innovative, why not start with giving women someone to call if they think that their membranes have ruptured? Just a few simple questions will usually sort out what’s happening, and will also give women an idea of what to look for next time. Here in Ontario, midwives routinely provide this service. Unfortunately, obstetricians’ patients usually have to take a trip to hospital. That’s where an info line could really come in handy… but definitely the nitrazine pads would not be something I’d recommend.

    October 30th, 2007 at 11:08 am

  3. Melissa A says:

    I used a ph strip from a pool supply store, and it worked perfectly. I’ve got about 30 left so I’ll have them for any future pregnancies. The nurses at the hospital thought it was a great idea, and it kept me from going to the hospital unecessarily.

    October 31st, 2007 at 7:52 am

  4. mari says:

    melissa a – please explain what the ph strip should read if the water is broke. my daughter is gushing little to medium spurts of what she thought was her amniotic fluid. the doctor did a test and we were shocked that her water had not broke. after she got home, it is continuing. the doctor said it is just discharge?? now she won’t know if her water breaks, unless it’s a huge gush, because of this discharge? those strips would help, but i need to know how to read them. thanks.

    November 19th, 2007 at 6:17 pm

  5. Anna Taylor says:

    Actually, most doctors will happily provide pregnant patienst with some sample strips or a whole roll of nitrazine test paper. Just ask your doctor. To use, you just swab as close to the cervix as you can get (with a Q-tip) and then apply the wettened tip to the nitrazine paper. I believe a color of blue indicates a positive for amnio fluid, however, there is always a risk of a false positive. But a false positive on a nitrazine strip is always less embarassing than it just being urine!

    December 20th, 2007 at 7:03 pm

  6. Grayson Morris says:

    While I agree that under normal circumstances these pads may lead to unnecessary intervention, there is one situation where they can be life-saving: when a woman has vasa previa. In a VP pregnancy, unprotected fetal blood vessels traverse the amniotic sac “down low”, between the baby and the cervix. When the woman’s water breaks, often these vessels will also rupture, and the baby can bleed to death–literally–within minutes. VP must be managed by vigilant attention to impending labor and a c-section before the woman’s water breaks. If her water breaks before the scheduled c-section, an emergency section must be performed within an extremely short window of opportunity. Knowing that she is leaking amniotic fluid would give a VP mother a vital edge in protecting her baby.

    Note also that in a VP pregnancy, the Amniosense false positive on contact with even trace amounts of blood would actually be a good thing.

    February 7th, 2008 at 6:29 am

  7. susie says:

    I really dislike those pads. I was givin one from a private hospital and it turned blue so i went off to the public hospital cause they said i will need to be admitted. they admitted me done an internal swob test and it was negative but kept me in anyways just incase it was leaking. and put me on high doses of antibiotics incase of infecttion. A few days later i was just curious to see if everything was ok, so i went back to the hospital and got a pad to take home. Took it home and it went blue again- positive-. I rang the hospital to ask if anything else could change the colour and they said yes your own body can just change it to a positive resault. I rang my obsitrician and she rang the hospital and told me to get in straight away though. So off to the hospital again. With all my bags packed this time. I am 5 1/2 months pregnant only 23 weeks. So i was looking to stay in for the next few months. They done and internal examination and it was negative. So they sent me home. SO i really think that those pads are rediculous. oh btw also had an ultrsound when i was in the hospital and it was all fine. so im thinking that they had me in there for nothing on antibiotics which im the kind of person that wont even take a panadol for a headache through pregnancy. I disagree with the acuracy of these pads.

    May 29th, 2008 at 4:47 pm

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