**5.1 Which investigations are beneficial?**

### **5.1.1 Basic Assessment**

Every patient who presents with reduced FM over 24 weeks gestation should have the following assessed:


#### **5.1.2 Symphyseal fundal height measurement (SFH)**

A clinical opinion about the size of the baby including abdominal palpation and the measurement of SFH should be part of every assessment and is helpful in the management of reduced FM. Despite the fact that abdominal palpation only detects 30% of small for gestational age fetuses (RCOG, 2002), SFH measurement has a positive predictive value of 60% and a negative predictive value of 76.8% (Heazell *et al*., 2005). This implies that if the SFH is within normal limits, fetal growth restriction or placental insufficiency is unlikely to be present. Serial SFH measurements have an increased specificity and sensitivity (Heazell *et al*, 2005; Pearce & Campbell, 1987) as the trend in growth is of more value than a single measurement in predicting poor fetal outcome. As 50-70% of fetuses with a birthweight below the 10th centile are constitutionally small (RCOG, 2002), Gardosi *et al* suggested that plotting measurements on customised SFH charts adjusted for maternal weight, height, parity and ethnic group results in increased detection of growth restriction and fewer hospital referrals (Gardosi & Francis, 1999). The SFH mean at 36 weeks gestation on drawn charts is 34-34.8cm (Calvert, Quaranta, Nottingham) which implies that using '*SFH in cm equals gestational age in weeks*' would lead to significant over-diagnosis of SGA fetuses.

We conclude that, in the absence of anything better, the measurement of SFH and its plotting on customised charts is recommended in selecting which patients should undergo further investigation (Unterscheider *et al*., 2009).

#### **5.1.3 Non stress test – Cardiotocography (CTG)**

CTG it is widely accepted as the primary method of antenatal fetal monitoring to assess the current status of the fetus (Pattison & McCowan, 2000) but its use is particularly difficult and cannot be recommended before 28 weeks gestation (Preboth, 2000). Between 24 and 28 weeks gestation auscultation of the fetal heart may be sufficient and CTG can be performed. A reactive CTG is defined by two accelerations exceeding 15bpm, sustained for at least 15 seconds in a 20 minute period (Devoe, 1990). Loss of variability is associated with fetal sleep, sedation or central nervous system depression, including fetal acidosis. The absence of accelerations or appearance of decelerations along with a history of reduced FM may indicate fetal hypoxia (Lee & Drukker, 1979) and is associated with fetal demise and Caesarean section delivery (ACOG, 2000). CTG is useful in the detection of acute hypoxia

Reduced Fetal Movements 213

estimate fetal weight exist, and numerous growth curves have been designed to plot these serial measurements. In late gestation, a single AC measurement is more accurate than head measurement. AC measurements have reported sensitivities of 72.9-94.5% and specificities of 50.6-83.3% and EFW has sensitivities between 33.3-89.2% and specificities of 53.7-90.9% (RCOG, 2002). AC and EFW measurements are better to predict a small for gestational age fetus under the 10th centile than large for gestational age fetuses (RCOG, 2002). Similar to SFH, serial measurements, ideally two weeks apart, are more accurate than single estimates in the prediction of growth restriction. As with SFH measurements they can be plotted on

In conclusion, fetal biometry assessment should be performed if SFH suggests SGA and if there is suspected oligohydramnios. The most common single cause of stillbirth is intrauterine growth restrition, therefore sonographic assessment is recommended if small fetal size is suspected or if the clinical assessment is limited, i.e. in case of increased maternal body mass index. It should also be considered in second and subsequent presentations or if neither pregnant woman nor clinician are reassured by the initial assessment (Unterscheider

The correlation with placenta derived factors such as reduced first trimester pregnancy associated plasma protein-A (PAPP-A) or placental protein-13 (PP-13) may suggest underlying placental dysfunction in patients with reduced FM. Fetal biometry is

**5.2 Which investigations are of limited value in the management of reduced FM in the** 

There is little evidence for the use of UA Doppler velocimetry in the assessment of reduced FM. UA Doppler is of benefit in high-risk pregnancies including the assessment of IUGR pregnancies in order to reduce perinatal mortality (Neilson & Alfirevic, 2000) but has not been shown to be of value as a screening test for detecting fetal compromise in the general obstetric population. Korszun *et al* suggested that adding UA and uterine artery (Ut.A) Doppler velocimetries to conventional CTG in the assessment of reduced FM might be reassuring for the managing clinician. Dubiel *et al* compared CTG with UA Doppler in the assessment of 599 women with low risk pregnancies complaining of reduced FM; CTG and UA Doppler were normal in 93% of patients. The overall perinatal mortality in their study was 3.8%. They found that CTG seemed to be a better predictor of mortality and infant handicap than Doppler velocimetry. Sergent *et al* reported only one highly pathological UA

Doppler in their retrospective review of 160 pregnancies affected by reduced FM.

We conclude that UA Doppler is of limited use in the assessment of reduced fetal movements (Unterscheider *et al*., 2009). It is useful in the assessment of the IUGR fetus.

A fetal vibroacoustic stimulation test may elicit fetal heart rate accelerations and increased fetal body movements, and may reduce the incidence of non-reassuring CTG and subsequent obstetric intervention (Pearson & Weaver, 1976). A Cochrane review by Tan &

customised centile charts to increase sensitivity and specificity.

recommended in such cases (Warrander *et al.*, 2011).

**5.2.1 Umbilical artery (UA) Doppler velocimetry** 

**5.2.2 Fetal vibroacoustic stimulation test** 

*et al*., 2009).

**low risk population?** 

but is a poor test for chronic hypoxia (Heazell *et al*., 2005). Large scale studies show that CTG does not reduce stillbirth or perinatal morbidity (Pattison & McCowan, 2000). Nevertheless a reactive CTG is significantly more likely to be followed by a normal delivery and a normal perinatal condition than non-reactive tests (Neldam, 1986).

Computerised CTGs are in use in many units in the United Kingdom and suggested to be more reliable, objective and accurate than visual inspection (Dawes *et al*., 1996). Fetal heart rate measurements are automatically calculated by a computer, and compared to reference values (centiles) according to gestation. The use of computerised CTG improves discrimination between normal and questionable records in gestations ranging from 24-42 weeks.
