By:DR. SALAH ROSHDY Professor of OB/GYN Qassim College of Medicine,KSASohag University,Egypt
IntroductionMaternal perception of decreased fetal movements (FMs) is a cause of concern and a common reason for visits to the antenatal clinic or delivery room. Several studies have shown that a reduction or cessation of FMs may result in poor pregnancy outcome and increased risk of serious perinatal morbidity and mortality.
However, the assessment and management ofpregnancies with reduced FMs is challenging and controversial. When signs of a compromised fetus are detected, there is a need for appropriate action, but the risk of iatrogenic damage must be considered.
Fetal activity in normal pregnanciesFM is one of the first signs of fetal life. Fetal activity serves as an indirect measure of central nervous system integrity and function. Regular FM can, therefore, be regarded as an expression of fetal well-being . Pregnant women usually sense FM from 18 to 20 weeks of gestation . Some multiparous women may perceive FMs at 16 weeks of gestation . As pregnancy proceeds, the weekly number of FM increases, peaking between 29 and 38 weeks of gestations.
These complex and integrated FM require a certain neuromuscular development and a normal metabolic state of the central nervous system. A gradual decline in the total amount of FM during the last trimester is suggested to be due to improved coordination and reduced amniotic fluid volume coupled with the increased fetal size .
Decreased FMsThe fetus responds to chronic hypoxia by conserving energy. Subsequent reduction in FMs has been described as an adaptive mechanism to reduce oxygen consumption . The human fetus is characterized by wide ranges of normal variation in FM, resulting in difficulty to define what constitutes a clinically important reduction in FM. Unable to quantify normal FMs, most investigators have resorted to arbitrary answers. Differences between the activities of individual fetuses and the perception of individual mothers are probably the major component of the variation in the FMs. There is at present no general agreement as to what constitutes decreased FM .
Table I. Factors associated with decreased fetal mov.Maternal anxietyBusy motherAlcohol useSedative useCorticosteroidsFetal sleepIntrauterine growth retardationHypoxiaHypothyroidismFetal anemiaNeurological or muscular abnormalityPoly- or oligohydramnios
Monitoring of FMs by the pregnant womanBecause fetal motor activity may reflect the fetal condition in utero, maternal counting of FMs has been suggested as a useful method for monitoring fetal condition .Several methods for monitoring FM have been described. However, neither the optimal number of movements nor the ideal duration for counting has been determined. Most of these methods imply long and repeated daily counting sessions. A simple screening program is the count-to-ten technique by Pearson .
Moore et al. have shown that the count-to- ten method of FM is effective in reducing the intrauterine death rate in low-risk pregnancies. The intrauterine death rate fell from 8.7 to 2.1 per 1000 after initiation of the FM program and was associated with a significantly higher proportion of labor inductions and cesarean sections for fetal distress .
Rayburn et al. have studied the hypothesis that the maternal perception of FM is as useful as antepartum FHR testing [non- stress test (NST) and contraction stress test (CST)] in high-risk pregnancies. They concluded that an active fetus (four or more movements perceived for each convenient hour of daily counting) is as predictive as a normal FHR testing for a favorable perinatal outcome .
Application of FM counting to low-risk pregnancies is attractive, because about half of stillbirths occur without obvious cause . However, presently there is no conclusive evidence of a reduction in the antepartum death rate by introducing a formal counting program of FM.
Assessment of fetal well-being in pregnancies with decreased FMThe fact that the compromised fetus reduces its oxygen requirements by diminishing activity could indicate that the reduced fetal activity is an expression of fetal distress and placental dysfunction . Thus, there is a need for fetal assessment in this situation. During the last decades, new methods for fetal assessment in various clinical settings have been introduced. These include NST (CTG), CST, vibroacoustic stimulation, Doppler velocimetry [umbilical artery (UA) and uterine artery (Ut.A)], biophysical profile, and the real-time ultrasonography.
Cardiotocography (NST and CST)CTG is applied to pregnancy complications where fetal well-being is questioned, including reduced FMs, post-term pregnancy, hypertensive disease, growth restriction, and bleeding in pregnancy .FMs and the onset of FHR accelerations are synchronized and coordinated functions . In a study by Rabinowitz et al. , adequate accelerations have been reported in the association with 79% of FMs perceived by the mother and 99% of FMs seen sonographically. Lee and Drukker have
demonstrated that absence of accelerations or appearance of decelerations concomitant to FM may indicate the beginning of fetal hypoxia. FHR decelerations during a CTG that persist for 1 min or longer are associated with a markedly increased risk of both cesarean delivery and fetal demise .The non-stress CTG with the loss of reactivity is associated most commonly with a fetal sleep cycle but may result from any cause of central nervous system depression, including fetal acidosis .
The CST is based on simultaneous recording of the FHR and uterine contractions induced by the administration of oxytocin. It is assumed that fetal oxygenation may be transiently reduced by the uterine contractions. Therefore, in the suboptimally oxygenated fetus, the resultant intermittent reduction in oxygenation will lead to late decelerations in FHR .
Nageotte et al. have examined the outcome of pregnancies in high-risk patients whose last antepartum fetal assessment was a normal CST or a normal modified biophysical profile [a combination of a NST (CTG) and an amniotic fluid index]. In this study, the frequency of adverse perinatal outcome following a normal modified biophysical profile was not significantly higher than that following a normal CST.
A meta-analysis of four studies has assessed the effects of antenatal CTG on perinatal morbidity and mortality in high-risk and intermediate-risk pregnancies. There were no significant effects of CTG monitoring on rates of stillbirth or measures of perinatal morbidity.
Fetal vibroacoustic stimulationFetal sleeping periods can lead to falsely nonreactive CTG tests, thus increasing the risk of unnecessary obstetric intervention . A vibroacoustic stimulus may elicit FHR accelerations, which appear to be valid in the prediction of fetal well-being . Tan and Smyth concluded in a meta-analysis of seven trials that fetal vibroacoustic stimulation could reduce the number of non-reactive CTG tests. Such stimulation offers the advantage of safely reducing overall testing time by reducing the number of non-reactive CTG traces due to fetal sleep states .
Doppler velocimetry (UA and Ut.A)The use of Doppler ultrasound to investigate the pattern of waveforms in the UA was first reported in 1977 . It has been evaluated more rigorously than any other biophysical test of fetal growth and well-being . UA Doppler velocimetry has not been shown to be of value as a screening test for detecting fetal compromise in the general obstetric population . Neilson et al. have published a meta-analysis of 11 studies of the effects of Doppler ultrasound in high-risk pregnancies.
Compared to no Doppler ultrasoundexamination, Doppler ultrasound in high-riskpregnancies (especially those complicatedby hypertension or presumed IUGR) wasassociated with a trend to a reduction inperinatal deaths and was also associatedwith fewer inductions of labor. There wereno significant differences in rates of fetaldistress in labor or cesarean delivery.
Dubiel et al. compared the use of CTG and UA Doppler velocimetry in low-risk pregnancies where decreased FM was the only indication for fetal assessment. They found that the CTG seemed to be a better predictor of mortality and infant handicap than Doppler velocimetry.
Adding UA and Ut.A Doppler velocimetries to the conventional CTG surveillance might be of clinical value in cases with decreased FM .
Biophysical profileSeveral studies have suggested a link between low biophysical scores and poor pregnancy outcome, resulting in its widespread use, particularly in the United States and Canada .Manning et al. have proposed that the combined use of five fetal biophysical variables as a more accurate means of assessing fetal wellbeing than any one used alone.
A meta-analysis of four studies has assessed the effects of biophysical profile tests on pregnancy outcome in high-risk pregnancies (decreased FM, hypertension, IUGR, post-term pregnancy, diabetes, previous stillbirth, antepartum hemorrhage, premature labor, and Rhesus disease). The effects of biophysical profile testing on perinatal outcome were not significantly different when compared with conventional fetal monitoring (usually CTG). At present, the data are insufficient to reach any definite conclusion about the benefit of the biophysical profile as a test of fetal well-being in high-risk pregnancies .
Real-time ultrasonographyReal-time ultrasonography enables the detection of several variables (Table III) . Whitty et al. studied a low-risk population whose only complaint was decreased FM. Initial testing included a CTG and an ultrasound examination. Approximately 9% of patients have incidental
abnormal ultrasonographic findings, and itwas concluded that ultrasound examination ofthese low-risk patients with the onlycomplaint of decreased FM might provideuseful information . However, there is a needfor further studies of the use ofultrasonography in this situation.
The ultrasound observations made when decreased fetalmovement perception persists•Fetal weight To evaluate the possibility for intra-uterine growth retardation.•Fetal movement Three or more discrete movements within 30 min•Fetal breathing movements One or more movements within 30 min•Evaluation of the amniotic fluid A single pocket of amniotic fluidvolume exceeding 2 cm is considered as adequate amniotic fluid•Malformations Should be excluded
Management of pregnancies with decreased FMsOnly few studies have presented management guidelines for pregnancies with decreased FM. It should be noted that none of these guidelines have been evaluated in randomized controlled trials.
Cont.• Patients with decreased FM & abnormal CTG require further investigation.• Patients with decreased FM & a normal CTG ,normal AFV,& no other indication for examination do not require follow-up testing.• If there is a continuing complaint of decreased FM ,it seems reasonable to undertake a follow-up evaluation.
American College of Obstetricians and Gynecologists (ACOG) , it is suggested that maternal complaints of decreased FM should be evaluated by a NST and modified biophysical profile (NST combined with determination of the amniotic fluid volume) to exclude imminent fetal jeopardy. If these tests are abnormal, the patient should be further evaluated by a CST and/or a full biophysical profile. If the woman continues to report decreased FM, a reassuring test should
be repeated periodically (either weekly ortwice weekly). However, it was concludedthat antepartum fetal surveillance has notdefinitively demonstrated improved perinataloutcome and that ACOG’s recommendationsare based on limited and inconsistentscientific evidence .
CTG Deviantly CTG Repeated CTG If still deviantly CTS abnormal the same day may be a CTSNormal, in an otherwise No further investigationUncomplicated pregnancy if FM are normal Consider:Decreased FM perception persists Induction Of Labor Ultrasound examination: Decreased FM Decreased FM USG normal perception persists perception persists Fetal weight, movements, Or breathing movements, USG Abnormal Cesarean Decreased FM Repeated CTGMalformations, and evaluation next step perception persists the same day SectionOf the amniotic fluid volume Doppler flow velocimetry Reporting of normal fetal activity again Repeated USG after 1-2weeks Flow chart for proposed management of decreased Fetal movements after 28weeks of pregnancy. CST, Contraction stress test; CTG, cardiotocography; FM, fetal movement.
ConclusionA perception of decreased FMs is frequently reported by pregnant women and causes much concern. However, there is no universal agreement on the definition of decreased FMs, or whether this is associated with a poor pregnancy outcome. Formal counting of FM by the pregnant woman could possibly find the fetuses, which have stopped performing strong, complex movements but still are in a
reasonably good health, allowing forintervention. Presently, the benefit of thisprotocol has not been definitely proven.CTG, UA/Ut.A artery Doppler velocimetry,and ultrasonography have been used forantepartum fetal assessment in pregnancieswith decreased FMs, but the evidence of aclinical benefit is not convincing. The effectsof fetal assessment with vibroacousticstimulation and biophysical profile areunknown and should be further evaluated.
Present recommendations regarding the management of pregnancies with a complaint of decreased FMs are based on limited and inconsistent scientific evidence. There is a need for well-designed studies in order to provide evidence-based guidelines in the future.