Third Trimester Prenatal Testing

Are all these third trimester prenatal tests necessary? It’s the common thought that runs through the minds of moms and dads-to-be everywhere.  Most commonly swamped with screenings and blood work during your first trimester, you are long past the majority of those difficult decisions by your last couple of months.  None the less, knowledge is power, and understand why you and your baby need these screenings  can help you make more informed decisions about both yours, and your baby’s care.

Group B Strep

Perhaps one of the last specific screenings needed is your Group B Strep (GBS) screening.  GBS, a bacteria that colonizes the gastrointestinal tract of virtually everyone is a dangerous and sometimes deadly invader for babies.  Every woman will be screened for GBS on or around your 36th week. The test is simple—your provider will take a quick swab of your vaginal and rectal areas and send the test off to look for the presence of GBS.   A large number of women are colonized with GBS and will need to be treated with antibiotics for a few hours prior to delivery to help reduce the likelihood that the bacteria will be transferred to the baby during delivery.  Babies who have GBS infection may face serious illness, and even death.  It’s because of GBS’s highly infective nature that every woman should be screened.  If you deliver prior to 36 weeks, or your results aren’t back yet, your doctor may treat you while you are in labor “just in case”.

Non Stress Testing

If you have been diagnosed with pretty much any type of condition that could complicate your pregnancy, your doctor may send you for weekly non stress testing to assess your baby’s tolerance to life inside.  Women who are often making this regular trek include those with gestational diabetes, preeclampsia/high blood pressure, or babies who are growth restricted, just to name a few. Every case varies, but an NST may take just a few minutes, or an hour or longer to complete.  For the test, baby is monitored through the use of an ultrasound to assess heart rate.  The baby’s heart rate in utero can tell your doctor a lot about your baby’s oxygenation and tolerance to his or her environment.  The test simply monitors your baby’s heart rate in response to movement (it should go up) as proof that baby is happy, and as healthy as possible. This test can be a key component of spotting early signs of intolerance, decreasing oxygen supply to the baby, or fetal intolerances that may require intervention (like an induction or C-Section).

There are several other tests your doctor may recommend, including amniocentesis, biophysical profiles, and genetic assessments.  All of which may be necessary in your particular case, but that will be between you and your doctor.  So even if you may feel like you are constantly under the microscope, be patient—it’s all for the best of your baby, and your new life to come.