CASE 2 Patient with high BPP score and altered fetal movements delivered for nonreassuring fetal heart rate
Ms. Q was undergoing weekly BPPs for diet-controlled gestational diabetes and a prepregnancy body mass index (BMI) of 52. At 37 weeks’ gestation, she had a BPP score of 8/8. However, it took almost 30 minutes to see 2 discrete body or limb movements. Ms. Q mentioned to the nurse taking her vitals after the BPP that the baby’s movements had changed over the previous few days, especially after contractions. Ms. Q then completed a nonstress test (NST); she had 2 contractions and 2 fetal heart rate decelerations, each lasting approximately 60 seconds. Ms. Q was sent to labor and delivery for prolonged monitoring, and she was delivered that day for a nonreassuring fetal heart rate tracing. Meconium-stained amniotic fluid and a tight triple nuchal cord were noted at delivery.
BPP considerations
While considered an in-depth look at the fetal status, BPPs may not predict overall fetal well-being during acute changes, such as umbilical cord compression or placental abruption. BPPs take longer to complete, require a trained sonographer, and include components like fetal breathing that may be influenced by such factors as nicotine,6-8 labor,9 rupture of membranes,10 magnesium sulfate,11 and infection.12
If medically indicated, which antenatal surveillance technique is right for your patient?
Frequently used antepartum fetal surveillance techniques include maternal perception of fetal movement or “kick counting,” NST, BPP, modified BPP, contraction stress test (CST), and umbilical artery Doppler velocimetry.
Worldwide, the most common form of antenatal surveillance is fetal kick counting. It is noninvasive, can be completed frequently, may decrease maternal anxiety, may improve maternal-fetal bonding, and is free.13 According to the results of a 2020 meta-analysis of 468,601 fetuses, however, there was no difference in perinatal death among patients who assessed fetal movements (0.54%) and those who did not (0.59%).14 There was a statistically significant increase in induction of labor, cesarean delivery, and preterm delivery among patients who counted fetal movements. Women who perceive a decrease in fetal movement should seek medical attention from a health care provider.
An evaluation for decreased fetal movement typically includes taking a history that focuses on risk factors that may increase stillbirth, including hypertension, growth restriction, fetal anomalies, diabetes, and substance use, and auscultation with a fetal Doppler. In the absence of risk factors and the presence of a normal fetal heartbeat, pregnant women should be reassured of fetal well-being. In a pregnancy at greater than 28 weeks, a 20-minute NST can be completed as well; this has become part of the standard workup of decreased fetal movement in developed countries. A reactive NST indicates normal fetal autonomic function in real time and a low incidence of stillbirth (1.9/1,000) within 1 week.15
Additionally, by measuring the amniotic fluid volume using the largest maximal vertical pocket (MVP), clinicians can gain insight into overall uteroplacental function. The combination of the NST and the MVP—otherwise known as a modified BPP—provides both short-term acid-base status and long-term uteroplacental function. The incidence of stillbirth in the 1 week after a modified BPP has been reported to be 0.8/1,000, which is equivalent to stillbirth incidence using a full BPP (0.8/1,000).16 The negative predictive value for both the modified BPP and the BPP is 99.9%—equivalent.
The case for modified BPP use
The modified BPP requires less time, is less costly (cost savings of approximately 50%), does not require a specialized sonographer, and can be performed in local community clinics.
Perhaps the initial antepartum surveillance test of choice should be the modified BPP, with the BPP used in cases in which the results of a modified BPP are abnormal. ●