**5.1.4 Amniotic fluid index (AFI) or deepest vertical pool (DVP)**

There are three ways to assess liquor volume; these include AFI, DVP and subjective assessment. In 1980 Manning & Platt proposed the measurement of the DVP for assessment of fetal wellbeing. This was revised by Phelan in 1987 who suggested that four pockets are better than one. Some studies show that AFI has poor correlation with actual fluid volume and suggest that measuring the DVP is slightly more reliable in assessing liquor volume (Chauhan *et al*., 1997). This finding agrees with a recent Cochrane review on the use of AFI versus DVP which concluded that the DVP measurement in the assessment of amniotic fluid volume during fetal surveillance seems a better choice since the use of the amniotic fluid index increases the rate of diagnosis of oligohydramnios and the rate of induction of labour without improvement in peripartum outcomes (Nabhan & Abdelmoula, 2008). Table 3 shows the reference values for AFI and DVP according to gestation. An AFI less than 5cm is associated with adverse outcome.


Table 3. Reference values for Amniotic fluid index (AFI) and deepest vertical pocket (DVP)

In general, if reduced liquor volume is detected, further evaluation of the fetus is recommended, given the association of oligohydramnios with placental insufficiency, premature rupture of membranes and fetal renal abnormality. Lin *et al* found that oligohydramnios was present in 29% of growth restricted fetuses. An AFI or DVP measurement is also recommended in postdates pregnancies. The 5th centile for AFI at 37 weeks is 8.8cm (Moore) or 6.9cm (Magann).

#### **5.1.5 Fetal biometry**

A Cochrane review showed that routine ultrasound after 24 weeks gestation in low-risk pregnancy does not improve perinatal outcome (Bricker & Neilson, 2007). Nevertheless, if reduced FMs are reported, fetal ultrasound assessment for abdominal circumference (AC) or EFW is indicated in cases where SFH measurement suggests SGA. More than 40 formulas to

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

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

There are three ways to assess liquor volume; these include AFI, DVP and subjective assessment. In 1980 Manning & Platt proposed the measurement of the DVP for assessment of fetal wellbeing. This was revised by Phelan in 1987 who suggested that four pockets are better than one. Some studies show that AFI has poor correlation with actual fluid volume and suggest that measuring the DVP is slightly more reliable in assessing liquor volume (Chauhan *et al*., 1997). This finding agrees with a recent Cochrane review on the use of AFI versus DVP which concluded that the DVP measurement in the assessment of amniotic fluid volume during fetal surveillance seems a better choice since the use of the amniotic fluid index increases the rate of diagnosis of oligohydramnios and the rate of induction of labour without improvement in peripartum outcomes (Nabhan & Abdelmoula, 2008). Table 3 shows the reference values for AFI and DVP according to gestation. An AFI less than 5cm is

**deepest** 

Borderline: AFI 5-8cm (5% chance of oligohydramnios in 4 days) Normal: AFI 8-18cm (0.5% chance of oligohydramnios in 1 week)

Table 3. Reference values for Amniotic fluid index (AFI) and deepest vertical pocket (DVP)

In general, if reduced liquor volume is detected, further evaluation of the fetus is recommended, given the association of oligohydramnios with placental insufficiency, premature rupture of membranes and fetal renal abnormality. Lin *et al* found that oligohydramnios was present in 29% of growth restricted fetuses. An AFI or DVP measurement is also recommended in postdates pregnancies. The 5th centile for AFI at 37

A Cochrane review showed that routine ultrasound after 24 weeks gestation in low-risk pregnancy does not improve perinatal outcome (Bricker & Neilson, 2007). Nevertheless, if reduced FMs are reported, fetal ultrasound assessment for abdominal circumference (AC) or EFW is indicated in cases where SFH measurement suggests SGA. More than 40 formulas to

and a normal perinatal condition than non-reactive tests (Neldam, 1986).

**5.1.4 Amniotic fluid index (AFI) or deepest vertical pool (DVP)** 

weeks.

associated with adverse outcome.

Mean at term: AFI 12cm

adverse

weeks is 8.8cm (Moore) or 6.9cm (Magann).

**5.1.5 Fetal biometry** 

Polyhydramnios: DVP ≥ 8cm, AFI ≥ 20cm Oligohydramnios: DVP ≤ 2cm, AFI ≤ 5cm

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 customised centile charts to increase sensitivity and specificity.

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 *et al*., 2009).

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

#### **5.2 Which investigations are of limited value in the management of reduced FM in the low risk population?**

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

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.

#### **5.2.2 Fetal vibroacoustic stimulation test**

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 &

Reduced Fetal Movements 215

controlled trials does not support the use of BPP as a test of fetal wellbeing (Lalor *et al*., 2008). There was no significant difference between the groups in perinatal deaths (RR 1.33, 95% CI 0.60 to 2.98). Combined data from two high-quality trials suggest an increased risk of caesarean section in the BPP group (RR 1.60, 95% CI 1.05 to 2.44, n = 280, interaction test P = 0.03) (Tuffnell *et al*., 1991). Observational studies however suggest that BPP has a good negative predictive value, meaning that fetal death is rare in women in the presence of a

**6. Optimal management of reduced fetal movements prior to and beyond** 

Reduced fetal movements prior to 24 weeks gestation should be managed with auscultation of the fetal heart and clinical examination (basic assessment). Between 24 and 28 weeks gestation evidence suggests that fetal heart auscultation is sufficient for assessment, however CTG can be performed. The evaluation of a CTG can be difficult at this early gestation and its interpretation can be improved by computerised CTG applying the Dawson & Redmond criteria. It is essential to carry out a basic assessment including comprehensive stillbirth risk evaluation. If clinical examination is suggestive of small fetal size, ultrasound for fetal biometry, liquor volume and congenital structural abnormalities is

Beyond 28 weeks gestation, CTG should be part of the assessment of women presenting with reduced FM (refer to section 5.1.3). Figure 1 summarizes the recommended management approach to women presenting with reduced FM after 28 weeks gestation.

If normal

CTG next day Daily CTG

If concerns persist smoking

UA Doppler

FMH Metabolic BMI Drugs

> V/E, sweep Induction Delivery

Discharge home

AFI/ DVP

If abnormal If concerns persist

SGA Refer RCOG guideline No 31

Fig. 1. Reduced fetal movement assessment flowchart *(*Unterscheider *et al*., 2009)

normal BPP (Dayal *et al*., 1999).

**24 weeks' gestation** 

recommended.

First presentation

Detailed history Risk factors Maternal observations Auscultation/ CTG Abdominal palpation SFH measurement

Biometry (EFW)

Repeat anomaly scan

If concerns persist

If concerns persist

If normal If concerns persist

If reassuring

SFH<D Oligo?

Smyth examining 4,838 participants confirmed that fetal vibroacoustic stimulation reduced the incidence of non-reactive CTGs (RR 0.62, 95% CI, 0.52-0.74) and also reduced the overall mean testing time. The authors concluded that further randomised trials were needed to determine the optimal intensity, frequency, duration and position of vibroacoustic stimulation and also to evaluate the efficacy, predictive reliability, safety and perinatal outcome.

#### **5.3 Which investigations are of no value in the management of reduced FM in the low risk population?**

#### **5.3.1 Fetal movement counting (count-to-ten kickcharts)**

Formal fetal movement counting was first suggested in 1973 by Sadovsky & Yaffe. Sadovsky instructed women to count movements three times a day after meals. Counting movements using kickchart (Cardiff "count to ten" chart) is now more frequently employed. We have recently shown that 64% of obstetricians working in Ireland handed out kickcharts to patients presenting with reduced FM (Unterscheider *et al*., 2010) The use of kickcharts is easy, simple and can be done at home. However, in a large study of 68,000 women, Grant *et al* were unable to demonstrate a reduction in the incidence of antepartum fetal death using formal movement counting. They reported that formal FM counting by 1,250 women prevented, at best, one unexplained antepartum late fetal death and that a random adverse effect was just as likely ( Grant *et al*., 1989). The use of kickcharts increased attendences for assessment of fetal wellbeing (15.5% vs 9.8%) and was associated with a 2.6 fold increased obstetric intervention rate (Heazell *et al*., 2005; Whitty *et al*., 1991). Another report demonstrated higher intervention rates (32% vs 21%) and caesarean section rates (24% vs 14%) (Sinha *et al*., 2007).

In October 2003 NICE and the National Collaborating Centre for Women's and Children's Health published their guideline on the routine antenatal care of healthy pregnant women. They came to the conclusion that routine formal FM counting should not be offered. This statement has been renewed in their 2008 guideline. In contrast, the American College of Obstetricians and Gynaecologists supports formal movement counting. In their bulletin on antepartum fetal surveillance they instruct the woman to count 10 movements, preferably after a meal, and to write down the hours this takes (ACOG, 2000). They do not provide a definition of reduced fetal movements or advise a timeframe in which these movements should be achieved, which reflects the dilemma and controversy of the definition and management of reduced FM. cease FM

Although formal fetal movement counting is not recommended, women should be educated about the physiology of fetal movements and the need to seek assessment if movements change, decrease or cease given the association with stillbirth and the identification of these concerns in the recent CESDI report.

#### **5.3.2 Biophysical profile (BPP)**

The biophysical profile (BPP) combines a CTG with ultrasound assessment of fetal movements, fetal tone, fetal breathing movements and liquor volume. A score of 8-10 confirms fetal well-being. Lalor *et al* recently published their Cochrane review on the use of BPP in high risk pregnancies and report that the available evidence from randomised

Smyth examining 4,838 participants confirmed that fetal vibroacoustic stimulation reduced the incidence of non-reactive CTGs (RR 0.62, 95% CI, 0.52-0.74) and also reduced the overall mean testing time. The authors concluded that further randomised trials were needed to determine the optimal intensity, frequency, duration and position of vibroacoustic stimulation and also to evaluate the efficacy, predictive reliability, safety and perinatal

**5.3 Which investigations are of no value in the management of reduced FM in the low** 

Formal fetal movement counting was first suggested in 1973 by Sadovsky & Yaffe. Sadovsky instructed women to count movements three times a day after meals. Counting movements using kickchart (Cardiff "count to ten" chart) is now more frequently employed. We have recently shown that 64% of obstetricians working in Ireland handed out kickcharts to patients presenting with reduced FM (Unterscheider *et al*., 2010) The use of kickcharts is easy, simple and can be done at home. However, in a large study of 68,000 women, Grant *et al* were unable to demonstrate a reduction in the incidence of antepartum fetal death using formal movement counting. They reported that formal FM counting by 1,250 women prevented, at best, one unexplained antepartum late fetal death and that a random adverse effect was just as likely ( Grant *et al*., 1989). The use of kickcharts increased attendences for assessment of fetal wellbeing (15.5% vs 9.8%) and was associated with a 2.6 fold increased obstetric intervention rate (Heazell *et al*., 2005; Whitty *et al*., 1991). Another report demonstrated higher intervention rates (32% vs 21%) and caesarean section rates (24% vs

In October 2003 NICE and the National Collaborating Centre for Women's and Children's Health published their guideline on the routine antenatal care of healthy pregnant women. They came to the conclusion that routine formal FM counting should not be offered. This statement has been renewed in their 2008 guideline. In contrast, the American College of Obstetricians and Gynaecologists supports formal movement counting. In their bulletin on antepartum fetal surveillance they instruct the woman to count 10 movements, preferably after a meal, and to write down the hours this takes (ACOG, 2000). They do not provide a definition of reduced fetal movements or advise a timeframe in which these movements should be achieved, which reflects the dilemma and controversy of the definition and

Although formal fetal movement counting is not recommended, women should be educated about the physiology of fetal movements and the need to seek assessment if movements change, decrease or cease given the association with stillbirth and the identification of these

The biophysical profile (BPP) combines a CTG with ultrasound assessment of fetal movements, fetal tone, fetal breathing movements and liquor volume. A score of 8-10 confirms fetal well-being. Lalor *et al* recently published their Cochrane review on the use of BPP in high risk pregnancies and report that the available evidence from randomised

**5.3.1 Fetal movement counting (count-to-ten kickcharts)** 

outcome.

**risk population?** 

14%) (Sinha *et al*., 2007).

management of reduced FM.

change,

concerns in the recent CESDI report.

**5.3.2 Biophysical profile (BPP)** 

controlled trials does not support the use of BPP as a test of fetal wellbeing (Lalor *et al*., 2008). There was no significant difference between the groups in perinatal deaths (RR 1.33, 95% CI 0.60 to 2.98). Combined data from two high-quality trials suggest an increased risk of caesarean section in the BPP group (RR 1.60, 95% CI 1.05 to 2.44, n = 280, interaction test P = 0.03) (Tuffnell *et al*., 1991). Observational studies however suggest that BPP has a good negative predictive value, meaning that fetal death is rare in women in the presence of a normal BPP (Dayal *et al*., 1999).
