Tests for Premature Rupture of Membranes
Premature Rupture of Membranes: What Is it?
In pregnant women, premature rupture of membranes (PROM) occurs when the amniotic sac that surrounds the baby (the membrane) breaks before the start of labor. It is more commonly referred to as “when your water breaks.” Membrane rupture that occurs before the 37th week of a pregnancy is called preterm PROM (PPROM). PPROM occurs in about 3 percent of pregnancies and causes about one-third of preterm births, according to the American Family Physician. It occurs more frequently in twin pregnancies.
The earlier your membranes rupture, the more serious it is for you and your baby.
- If your pregnancy is past 37 weeks and your membranes rupture, your baby is ready to be born.
- If your pregnancy is less than 37 weeks and your membranes rupture, your doctor will have to decide whether to deliver your baby immediately or to try to continue the pregnancy. Your doctor may choose to induce your labor early due to the risk of infection to your baby.
Women who deliver within 24 hours after their water breaks are less likely to get an infection, so it’s important to go to the hospital as soon as possible after the membranes rupture. At the hospital, simple tests can confirm that your membranes have ruptured.
What Are the Symptoms of Premature Rupture of Membranes?
The biggest sign of PROM is fluid leaking from the vagina. The fluid might trickle slowly or it might gush out. Women sometimes mistake the fluid for urine.
If you notice leaking fluids, use a pad or paper to absorb some of the fluid. Look at it and smell it. Amniotic fluid shouldn’t smell like urine and usually has no color.
Other signs may include:
- a feeling like you are unable to stop urinating
- vaginal discharge or wetness that is more than normal
- bleeding from the vagina
- pelvic pressure
If you think your membranes have ruptured, call your doctor right away.
Diagnosing Premature Rupture of Membranes
If you suspect that your water has broken and there is fluid leaking from the vagina, your doctor will need to confirm that the membranes have actually ruptured.
Your doctor will examine you and observe the fluid coming from the vagina. Your doctor will then order tests to help confirm PROM or PPROM. Tests for PROM involve analyzing vaginal secretions to determine if amniotic fluid is present. Since the fluids might be contaminated with blood or other secretions, these tests look for substances or certain characteristics that are normally only found in amniotic fluid. Your doctor will collect some fluid from the vagina using a medical tool called a speculum in order to do most of these tests. A doctor will insert the speculum into the vagina and gently spread apart the vaginal walls. This allows the doctor to examine the inside of the vagina and to collect fluid directly from the vagina.
This test involves testing the pH of a sample of vaginal fluid. Normal vaginal pH is between 4.5 and 6.0. Amniotic fluid has a higher pH of 7.1 to 7.3. Therefore, if the membranes have ruptured, the pH of the sample of vaginal fluid will be higher than normal.
This test involves putting a drop of fluid obtained from the vagina onto paper strips containing Nitrazine dye. The strips change color depending on the pH of the fluid. The strips will turn blue if the pH is greater than 6.0. A blue strip means it’s more likely the membranes have ruptured.
This test, however, can produce false positives. If blood gets in the sample or if there is an infection present, the pH of the vaginal fluid may be higher than normal. Semen also has a higher pH, so recent vaginal intercourse can produce a false reading.
If your water is broken, the fluid mixed together with estrogen will create a “fern-like” pattern under a microscope due to salt crystallization. A few drops of fluid will be placed on a microscope slide and observed under a microscope.
Other tests for diagnosing PROM include:
- Dye test: Injecting dye into the amniotic sac through the abdomen. If the membranes have ruptured, the colored fluid will be found in the vagina within 30 minutes.
- Tests that measure the levels of chemicals known to exist in the amniotic fluid but not in vaginal fluid. These include prolactin, alpha-fetoprotein, glucose, and diamine oxidase. High levels of these substances mean that the membranes have broken.
- Newer noninvasive tests such as the AmniSure ROM test from QIAGEN Sciences. This test does not require a speculum examination. It works by detecting the placental alpha microglobulin-1 biomarker in the amniotic fluid.
Once PROM is confirmed, your doctor will likely perform additional tests to assess the following:
- the presence of infection by testing the amniotic fluid
- the degree of fetal lung development, to determine if the baby’s lungs are mature enough to operate outside the womb
- the status and health of the fetus, including listening to the baby’s heart rate
If you are at term (more than 37 weeks pregnant), you may go into labor naturally or your doctor may induce labor to help reduce the risk of infection.
If your doctor decides to delay delivery, they should continue to monitor you and your baby to make sure that this decision remains the best course of action. If the baby’s heart rate drops, immediate delivery is essential.
Are There Complications to PROM?
The biggest risk of PROM is infection. If the uterus becomes infected (chorioamnionitis), the baby must be delivered immediately. An infection can cause serious problems for the baby.
For preterm PROM, the biggest risk is a preterm delivery, which increases risks of complications for the baby. These complications include:
- learning disabilities
- neurological problems
- respiratory distress syndrome
Another serious complication is umbilical cord compression. Without amniotic fluid, the umbilical cord is vulnerable to damage. The umbilical cord delivers oxygen and nutrients to the baby and is normally protected by the amniotic fluid. If the fluid leaks out, the umbilical cord may get compressed between the baby and the uterus or in some cases, fall out of the uterus into the vagina. This can lead to serious brain injuries and even death.
Preterm PROM before the 24th week is rare. However, it often results in the death of the fetus because the baby’s lungs are not able to develop properly. If the baby survives, they will often have long-term problems, including:
- chronic lung disease
- developmental problems
- cerebral palsy
What Happens Next?
What happens next depends on the stage of your pregnancy.
37 Weeks and Up
Your doctor will proceed to deliver your baby. Labor might occur by itself (spontaneously) or your doctor may induce labor using certain medications.
Near Term (34 to 36 weeks)
Your doctor will likely proceed to deliver the baby if the hospital has neonatal care available. According to Sanford Health, two-fifths of women at this stage will deliver the baby within a week. Many will deliver within 48 hours.
Preterm (Less than 34 weeks)
Unless the baby’s lungs are fully mature, the doctor will want to wait to induce labor. You will talk about your own situation and the risks and treatment options available to you and your baby.
Medications might include:
- antibiotics to prevent infections
- steroid injections to speed up the development of the baby’s lungs
- drugs to prevent contractions
Your doctor will also closely monitor you and your baby with regular ultrasounds and to check for infections. You may have to stay in bed during this time.
What Is the Outlook?
The outlook depends on the stage of your pregnancy. Babies born too early are at a higher risk of complications. Despite attempts to prolong a pregnancy after PPROM, many women will deliver within one week. PPROM results in fetal death in 1 to 2 percent of cases, according to the American Family Physician.
How Can I Prevent PROM?
You can’t always prevent PROM, but certain lifestyle changes can reduce your risk. A history of sexually transmitted diseases and smoking during pregnancy can increase your risk of having PROM (smoking should be avoided).
Talk to your doctor if you take steroid medications. They may recommend that you stop taking them if they are not absolutely necessary for treating another problem
Exercise during pregnancy is OK, but you should talk to your doctor about the level of physical activity you can safely do during your pregnancy. Strenuous physical activity can also cause PROM.