The significance of fetal heart rate decelerations during nonstress testing

Single Sporadic Deceleration during Reactive Nonstress Test-Clinical Significance and Risk for Cesarean Delivery

OBJECTIVE

Evidence regarding the clinical significance of a single sporadic variable deceleration (SSD) in reactive non-stress test (NST) is scarce, and optimal management has yet to be established. We aim to evaluate whether SSD during a reactive NST at term is associated with a higher risk for fetal heart rate decelerations during labor and the need for intervention.

METHODS

This was a retrospective, case-control study of singleton term pregnancies at one university-affiliated medical center in 2018. The study group consisted of all pregnancies with an SSD in an otherwise reactive NST. For each case, two consecutive pregnancies without SSD were matched in a 1:2 ratio. The primary outcome was the rate of cesarean delivery (CD) due to non-reassuring fetal heart rate monitoring (NRFHRM).

RESULTS

84 women with an SSD were compared to 168 controls. SSD during antenatal fetal surveillance did not increase the rate of CD overall or for NRFHRM (17.9% vs. 13.7% and 10.7% vs. 7.7%, respectively, p > 0.05). Rates of assisted deliveries and maternal and neonatal complications were similar between the groups.

CONCLUSIONS

SSD during a reactive NST in term pregnancies is not associated with an increased risk for adverse perinatal outcomes. SSD should not necessarily require induction of labor, and expectant management is a reasonable alternative.

Antepartum Fetal Surveillance: ACOG Practice Bulletin, Number 229

The goal of antepartum fetal surveillance is to reduce the risk of stillbirth. Antepartum fetal surveillance techniques based on assessment of fetal heart rate (FHR) patterns have been in clinical use for almost four decades and are used along with real-time ultrasonography and umbilical artery Doppler velocimetry to evaluate fetal well-being. Antepartum fetal surveillance techniques are routinely used to assess the risk of fetal death in pregnancies complicated by preexisting maternal conditions (eg, diabetes mellitus) as well as those in which complications have developed (eg, fetal growth restriction). The purpose of this document is to provide a review of the current indications for and techniques of antepartum fetal surveillance and outline management guidelines for antepartum fetal surveillance that are consistent with the best scientific evidence.

Fetal assessment during pregnancy

Fetal monitoring during pregnancy is used to prevent fetal death. This article addresses the goals of fetal monitoring during pregnancy. Methods of fetal surveillance are reviewed, as well as the meaning of abnormal fetal testing and how these results relate to fetal and neonatal outcome. Overall, pediatricians who understand the goals, methods, and interpretation of fetal testing can communicate more effectively with the delivering obstetric team in anticipation of optimizing obstetric and pediatric outcomes.

Selected neurologic complications of pregnancy

Many neurologic disorders, such as eclampsia, pseudotumor cerebri, stroke, obstetric nerve palsies, subarachnoid hemorrhage, pituitary tumors, and choriocarcinoma, can develop in the pregnant patient. Maternal mortality from eclampsia, which ranges from 0 to 14%, can be due to intracerebral hemorrhage, pulmonary edema, disseminated intravascular coagulation, abruptio placentae, or failure of the liver or kidneys. Associated fetal mortality ranges from 10 to 28% and is directly related to decreased placental perfusion. Pseudotumor cerebri can be associated with serious visual complications; thus, the therapeutic goal is to prevent loss of vision. The risk of stroke in the pregnant patient is 13 times the risk in the nonpregnant patient of the same age. The major causes of stroke in pregnant patients are arterial occlusion and cerebral venous thrombosis. Lumbar disk prolapse is common in pregnant patients, and lumbosacral plexus injuries can occur during labor or delivery. In addition, peripheral nerve compression or entrapment syndromes are thought to be caused by the retention of fluid during pregnancy. The incidence of subarachnoid hemorrhage during pregnancy is 1 in every 10,000 patients, a rate 5 times higher than in nonpregnant women. Because of a proliferation of prolactin-secreting cells, the pituitary gland can enlarge dramatically during pregnancy, a change that can disclose a previously unknown tumor or cause a known pituitary tumor to become symptomatic. The incidence of choriocarcinoma is 1 in 50,000 full-term pregnancies but 1 in 30 molar pregnancies. This malignant tumor has a high rate of cerebral metastatic lesions. In addition to these disorders that develop during pregnancy, the pregnant state can affect numerous preexisting neurologic conditions, including epilepsy, headaches, multiple sclerosis, myasthenia gravis, spinal cord injury, and brain tumors. We discuss advice for patients with such conditions who wish to become pregnant, recommendations for medical and surgical management, and surgical considerations for neurologic complications during pregnancy.

Second-trimester fetal monitoring and preterm delivery in pregnancies with systemic lupus erythematosus and/or circulating anticoagulant

Antepartum fetal monitoring was initiated at 19 to 26 weeks' gestation in 15 pregnancies: six (five with systemic lupus erythematosus, one with circulating anticoagulant) with a complicated antepartum course (group 1); three, all systemic lupus erythematosus, with a normal antepartum course (group 2); and six normal control pregnancies (group 3). Group 1 all exhibited nonperiodic fetal heart rate decelerations, without the classical appearance of early, late, or variable decelerations, and four of the six had fetal bradycardia. In three group 1 cases, there was no active intervention because of early gestational age, and fetal death occurred at 23, 27, and 27 weeks, respectively. The other three patients in group 1 received betamethasone and were delivered by cesarean section at 28 to 30 weeks. There were no cases of respiratory distress syndrome or neonatal death. Five of the six infants in group 1 were small for gestational age. The nonperiodic fetal heart rate decelerations were absent in both groups 2 and 3 who all had normal fetal outcomes at term. The abnormal finding of women with nonperiodic fetal heart rate decelerations at 20 to 28 weeks may detect the fetus at risk for intrauterine death in pregnancies complicated by systemic lupus erythematosus or circulating anticoagulant. Continued surveillance, steroid induction of lung maturity, and delivery should be considered in these cases.

Variable decelerations during nonstress tests are not a sign of fetal compromise

An examination of 908 fetal heart rate tests of 418 consecutive patients revealed brief variable decelerations in more than 50.7% of the patients. Although an association existed with nuchal cord location found at delivery, no association existed between these variable decelerations and fetal heart rate decelerations during labor, low Apgar scores at birth, or birth weight. We find no evidence to suggest that these brief variable decelerations are a sign of fetal compromise or an indication for obstetric intervention.