Antepartum Testing Health Article

Preparation

The health care provider gives a complete explanation to the pregnant woman about the test, what to expect, how long the test may take, what it means, and why it is being done. It frequently helps if the pregnant woman has eaten prior to undergoing the test.

Aftercare

If the test results are acceptable, the pregnant woman is instructed to continue following her current medical regimen and return for additional testing on the dates prescribed. For NSTs/CSTs, the time period between tests should be no longer three to four days under high-risk conditions. Ultrasounds should be rescheduled as the need dictates per the physician.

Complications

There are no complications per se from the tests themselves with the exception of unfavorable test results or supine (lying horizonally on the back) hypotension secondary to a pregnant woman lying on her back for an ultrasound with resultant vena cava (one of two large veins that return blood from peripheral circulation to the heart) compression.

Results

Usually, a report of normal results for NSTs provides reassurance that the fetus is healthy and should remain so for three to four days, at which time repeat testing will be necessary. A normal NST means the FHR accelerated at least 15 beats above the baseline FHR for 15 seconds within a 20-minute period of time. A non-reactive NST is one that fails to meet this criterion within an 80–90 minute period of time. For an extremely preterm fetus, a normal NST refers to reactive for gestational age or the FHR accelerated 10 beats above the baseline for 10 seconds over a 20–30 minute period. Typically, the central nervous system is not completely mature until approximately 32 weeks gestational age and this report takes that into consideration. It is important to remember that a normal result does not guarantee that no problems are present. Although very rare in occurrence, false normal results can be observed.

The CST results are reported as a reactive/negative, suspicious, or positive or non-reactive/negative, suspicious, or positive. The reactive/nonreactive part of the test report refers to the presence or absence of accelerations and the negative part refers to no decelerations being present with UCs. Suspicious and positive refer to the presence of decelerations with Ucs. This result requires further evaluation, i.e. prolonged EFM monitoring or a BPP. A normal BPP report is 8-10 points. Six points is suspicious and requires either a CST or a repeat BPP within 24 hours. A total of 4 points is not reassuring and requires immediate evaluation by prolonged EFM.

All results are given to the primary physician who must then make a decision as to the appropriate course of action. Abnormal CST results usually indicate the baby is not receiving sufficient oxygen and may not be able to withstand the stress of labor and vaginal delivery. If this is the case, a cesarean section may be performed. The final outcome depends on the mother's individual circumstances, i.e. severe pregnancy induced hypertension may require immediate delivery via cesarean section, and an extra large fetus of a diabetic mother may require the same. In some cases, medications may be given to the mother for her condition, and to speed up the lung maturity of the baby. If the mother's cervix is favorable for induction, labor may be induced.

Health care team roles

The physician is the head of a health team of interdisciplinary members and determines the medical regimen necessary for the pregnant woman, depending on whether the pregnancy is normal or high-risk. Nurses schedule the tests and provide the woman with the necessary information regarding the tests. Nurses must perform any tests that they conduct correctly, interpret them appropriately, and provide the necessary follow-up or interventions. They may utilize this time period with the woman for teaching, answering questions, and offering emotional support. The ultrasonographer performs the BPP and reports the results directly to the physician.