03.03 Antepartum Testing

In this lesson I will explain antepartum testing in detail and when each is used.

Many routine diagnostic exams are done throughout the pregnancy at various stages. Testing starts early in the prenatal period and is usually noninvasive. Routine tests might become more frequent or invasive if anything is detected that needs to be assessed further. Each pregnancy is different, no two pregnancies are the same so a patient could have 3 pregnancies and each be different and require different testing. Some women will have it easy while others will need more attention. The goal is to properly screen to detect issues/complications early and then appropriately address and support any issues that are found. Think of it as prophylactic and then it will go further if needed.
Let’s talk about the routine testing. This is not all of the tests, we're just going to talk about the most common and most important ones, but in your outline we've covered quite a few others that you can see in more detail. This is standard testing done on everyone. Besides basic lab work that is done there are a few other routine exams. Titers will also be drawn to see what the mother’s Rubella status is as well as Hep B. If mom is rubella non-immune she can not review the vaccine until after delivery. This will be important for you to remember. The rubella vaccine is live and could cross the placenta. We need to get her the vaccine after deliver to protect her in future pregnancies.STI testing will also be done because a lot of STIs can be harmful to the baby once born. The major STIs that are checked are HIV, HPV, herpes, gonorrhea, syphilis, chlamydia. Others might be tests or are obviously detected such as trichamonois, but whatever is found needs to be treated and followed up and passed on at delivery for further baby monitoring. Each patient will have a glucose challenge done at 28 weeks gestation. The first test is a one hour test. The patient drinks 50g oral glucose and a one hour glucose is taken. If they fail, meaning above 130-140 they need to have their 3 hour glucola done. The lab numbers will vary based on the facilities lab so refer to your book or class notes on what your specific numbers are. For the three hour glucola a fasting blood sugar is taken and the patient drinks 100g glucose. Her blood sugar is then checked at 1 hr, 2 hr, 3hr. If she fails 2 or more readings she is gestational diabetic.

.Other routine tests will be a urinalysis at each appointment. This will be used to detect protein for preeclampsia, glucose and bacteria. Nonstress test (NST) are noninvasive and not painful. A tocometer is placed to detect contractions and another for fetal heart rate. The patient will hit a button when she feels baby move and the nurse will assess what the heart rate does with movement. We want to see 15 beats above baseline at least twice in 20 min. If this happens it is reactive. We want reactive. This looks at overall fetal well being. Group beta strep also known as GBS is a test on every woman close to delivery. It is a vaginal swab taken at 34-37 weeks and it detects how much beta strep bacteria is present. The patient will either be positive or negative.
The contraction stress is performed if the patient’s NST is non-reactive. So it is done to assess the fetal well being better. Contractions will be induced either with pitocin or also nipple stimulation can cause a release of natural oxytocin for contractions to start. So using the breast pump can help. The fetal heart rate will be monitored for signs of stress to the contraction. If there is stress we see a decrease in FHR because of the contraction. Usually it will be late decelerations which is a fetal heart rate that drops after the start of the contraction. We want to have 3 contractions with no decelerations. This is a negative result which is what we want. It means negative for decelerations. Chorionic villus sample is very invasive and looks at genetics of the fetus. The testing is done early in gestation (11-14 weeks) and ultrasound guides as the chorionic villi from the placental tissue are taken for sample. The mother must call if she has contractions, cramping, fever, child, or leaking of fluid. This patient would not be calling for decreased fetal movement because it is done so early in gestation that movement isn’t felt. This is sometimes tricky on a test so I wanted to point that out. An amniocentesis is a similar test. An ultrasound guides as a large needle taken amniotic fluid. It is used to check for genetic and metabolic issues as well as fetal lung maturity. This patient would be instructed to call MD with any sign of decreased fetal movement, uterine contractions, cramping, fever, chills, and fluid leaking from site. It is the same as the chorionic villus sampling accept this test can be done later in gestation when movement is felt so this mother would notify for decreased fetal movement.
Education will vary by the test because they are all looking at different things. Education should be done on the procedure and what is being looked for so the patient understands. Education on whether the testing is fasting or nonfasting is needed so the patient can be prepared and the test can be done right. The patient might need to have a full bladder for some ultrasounds if she is early on so that the full bladder will push the uterus up out of the pelvis. Education on any signs and symptoms that need to be watched for and when to call MD is really important. Some of these invasive tests could lead to major complications so we need the patient to be aware what to watch for and when to call.


Comfort is an important concept because we need to keep mom comfortable during any of these procedures. Reproduction is a concept because we are performing these tests because she is reproducing and human development is one because we are ensuring that development is happening properly with these tests.
Antepartum testing are mostly noninvasive labs, ultrasounds, non stress tests, glucose tolerance tests. They can be invasive in times of needing further studies. The screening are used to check for complications that can be maternal or fetal.

Make sure you check out the resources attached to this lesson and compare and contrast the various tests and education to be given. Now, go out and be your best selves today. And, as always, happy nursing.