Did my water break? Tests used to tell if you have ruptured membranes.
Posted Dec 19 2009 5:24pm
Sometimes, medicine and nursing is not an exact science.
Many times, we have women come in to evaluate if their membranes are ruptured.There are several observations/tests used to determine if the membranes are possibly ruptured.
Test #1 – visual inspection of the labia: if things are saturated, you can pretty much guarantee that it’s ruptured membranes.
Test #2 – nitrazine paper: this tells the pH of the fluid.Acidic fluid doesn’t change the color of the yellow test paper.Alkaline fluids change the paper to a blue color.The darker the shade of blue, the more alkaline the fluid is.Several things can cause the nitrazine to test positive (change color): amniotic fluid, semen, vaginal mucous and secretions (vaginal fluids can have a very high pH), feces, and blood.So, you can see it’s not an exact test.
Test #3 – speculum exam: this is where we visualize the cervix and look for “pooling” of fluid from the cervix.This is usually a good indicator that it’s amniotic fluid.The provider will usually have the woman cough to help express any fluid from the uterus into the vagina.
Test #4 – looking at a specimen of the fluid on a slide under the microscope.This is where we look for a pattern called “ferning”.When amniotic fluid is placed on a slide and allowed to air dry, it will take on a distinctive ferning pattern under the microscope.However, amniotic fluid doesn’t fern before 20ish weeks, which makes this test difficult to use for diagnosis.
Test #5 – injection of indigo carmine into the uterus via an amnioscentesis.Indigo carmine is a bright blue dye.When it’s injected into the uterus via an amnio, we watch for fluid leakage out of the vagina.If the woman leaks blue fluid, then it’s positive.This is a very definitive test, but also very invasive and has some risks associated with it.
Test #6 – ultrasound: the provider looks for pockets of fluid around the baby.If the fluid pockets and measurements are adequate, then either there was a lot of fluid (polyhydramnios) in the first place, or the membranes haven’t leaked a significant enough to affect the level of fluid left around the baby.Sometimes, a high leak that seals itself will show normal fluid levels on an ultrasound.