MATERNAL AND EARLY CHILD HEALTH

Health Evidence Bulletins - Wales

Date of Completion: 23.6.97

The contents of this bulletin are likely to be valid for approximately one year, by which time significantly new research evidence may become available


14. Suspected fetal compromise in pregnancy and labour

(Users are advised to consult the supporting evidence for a consideration of all the implications of a recommendation)

Fetal compromise in pregnancy is difficult to assess, not least because the ability to predict fetal growth retardation is not the same as the ability to predict low birth weight. Many cases have no obvious cause and management has to be aimed at determining the optimum time of delivery.
In the prevention of poor fetal growth, maternal smoking, alcohol and drug addiction are potentially avoidable factors.
In labour, electronic fetal monitoring has been widely adopted in an attempt to identify the fetus at risk of hypoxia, and associated morbidity and long term damage, but this may conflict with maternal wishes(i). A full multidiscipplinary review of intrapartum fetal surveillance is available which covers etiology and technique and makes recommendations for practice (ii)
i. Internal Review Group (Type V evidence - expert opinion. See Contributors)
ii. Spencer JAD, Ward RHT (eds.). Intrapartum fetal surveillance.   Recommendations arising from the 26th RCOG Study Group. London: Royal College of Obstetricians and Gynaecologists, 1993
14.1 In PREGNANCY  
The Statements The Evidence
14.1a. Smoking cessation programmes, in particular behavioural strategies, can be effective for a small minority of smokers in increasing mean birthweight. Poorly structured advice may lead to some smokers spending their pregnancy in a state of guilt and inadequacy. There are no trials of pre-pregnancy intervention to determine if such advice reduces the prevalence of smoking or, more importantly, improves outcomes(i,ii).
(Health gain notation - 4 "unknown". The efficacy of smoking prevention programmes in general will be covered in the Healthy Living Bulletin - due for publication in 1998)
i. Dolan-Mullen P, Ramirez G, Groff JY. A meta-analysis of randomized trials of prenatal smoking cessation interventions. American Journal of Obstetrics and Gynecology. 1994; 171(5): 1328-1334. (Type I evidence - meta-analysis);
ii. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 244-247, 251
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 22-23)
14.1b. Excessive alcohol consumption in pregnancy is associated with increased morbidity and mortality in the fetus. While no trials of cessation programmes exist, guidelines on management are available (i).
(Health gain notation - 5 "potential for harm")
i. Royal College of Obstetricians and Gynaecologists. Alcohol consumption in pregnancy RCOG Guidelines No. 9. London: RCOG, 1996
(Type V evidence - expert opinion)
14.1c. There is no evidence to recommend nutrient therapy by dietary interventions and supplementation in suspected fetal growth impairment(i)i.

(Health gain notation - 5 "unlikely to be beneficial")

i. Gulmezoglu AM, Hofmeyr GJ. Nutrient treatment for suspected impaired fetal growth. Cochrane database of systematic reviews. Cochrane Library 1997 Issue 1.
(Type I evidence - systematic review of small trials with methodological limitations)

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14.1d. There is evidence of the value of an accurate early ultrasonic dating of all pregnancies in avoiding unnecessary induction for suspected poor growth (i,ii).

(Health gain notation - 2 "likely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 424-426
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 41);
ii. Managing post-term pregnancy. Drug and Therapeutics Bulletin 1997; 35(3): 17-18
(Type V evidence - expert opinion)
14.1e. In prediction of poor growth, measurement of fundal height has shown quite good specificity and sensitivity (i).

(Health gain notation - 2 "likely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 p. 415
(Type IV evidence - observational studies. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 62)
14.1f. Fetal movement counting has been widely used as a test of fetal compromise. The two randomised controlled trials available provided no evidence of reduction in intrauterine death (i).
(Health gain notation - 3 "trade-off between beneficial and adverse effects)
caveat: Its widespread use does result in more hospital attendances, induction and elective deliveries. Limiting to selected at risk cases may be better practice.
i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 440-452
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 62)

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14.1g. There is no evidence that routine screening by repeat biophysical profiles or Doppler studies identifies affected pregnancies(i,ii).

(Health gain notation - 5 "unlikely to be beneficial")

i. Neilson JP, Alfirevic Z. Doppler ultrasound in high risk pregnancies. Cochrane database of systematic reviews. Cochrane Library. 1997 Issue 4. (Type I evidence - systematic review);
ii. Alfirevic Z, Neilson JP. Biophysical profiles for fetal assessment in high risk pregnancies. Cochrane database of systematic reviews. Cochrane Library. 1997 Issue 1. (Type I evidence - systematic review)
14.1h. There is evidence that selective ultrasound is effective in identifying at-risk pregnancies but there is a need for prospective studies to identify optimum techniques(i).

(Health gain notation 21 "likely to be beneficial")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 420-436
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 63-70)
14.1i. There is evidence that Doppler studies, to monitor the high risk infant, are effective to determine the optimum timing of delivery (i).
(Health gain notation -1 "beneficial")
i. Neilson JP, Alfirevic Z. Doppler ultrasound in high risk pregnancies. Cochrane database of systematic reviews. Cochrane Library. 1997 Issue 4. (Type I evidence - systematic review)
14.1j. There is no evidence that biophysical profiles to monitor the high risk infant are effective in improving outcome(i)i.
(Health gain notation - 5 "unlikely to be beneficial")
i. Alfirevic Z, Neilson JP. Biophysical profile for fetal assessment in high risk pregnancies. Cochrane database of systematic reviews. Cochrane Library. 1997 Issue 4. (Type I evidence - systematic review)
14.1k. The value of hospitalization and bed rest for suspected fetal compromise have not been substantiated(i).

(Health gain notation - 5 "unlikely to be beneficial")

i. Gulmezoglu AM, Hofmeyr GJ. Hospitalisation for bedrest for suspected impaired fetal growth. Cochrane database of systematic reviews. Cochrane Library 1997 Issue 4. (Type II evidence - randomised controlled trial)
14.1l. External cardiotocography may be effective in identifying deteriorating fetal condition (in at-risk pregnancies) following suddent reduction of fetal movement or ante-partum haemorrhage(i).
(Health gain notation - 2 "likely to be beneficial")
caveat: Because of the difficulties in interpretation, its widespread use is not recommended
i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 479-492
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 66-67)

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14.1m. Preliminary and limited trial evidence gives initial support to the value of maternal oxygen therapy but this should only be used in the context of well-designed trials(i).
(Health gain notation - 3 "trade-off between beneficial and adverse effects")
i. Gulmezoglu AM, Hofmeyr GJ. Maternal oxygen therapy in suspected impaired fetal growth. Cochrane database of systematic reviews. Cochrane Library 1997 Issue 4.
(Type I evidence - systematic review of two trials)
14.1n. There is inadequate evidence at present to support the routine use of calcium channel blockers in pregnancy where the risk of impaired fetal growth is increased, but further trials are indicated (i).
(Health gain notation - 4 "unknown")
i. Gulmezoglu AM, Hofmeyr GJ. Calcium channel blockers in suspected impaired fetal growth. Cochrane database of systematic reviews. Cochrane Library 1997 Issue 4.
(Type II evidence - randomised controlled trial)
14.1o. Plasma volume expansion for impaired fetal growth is theoretically promising but further research is needed (i).

(Health gain notation - 4 "unknown")

i. Gulmezoglu AM, Hofmeyr GJ. Plasma volume expansion for suspected impaired fetal growth. Cochrane database of systematic reviews. Cochrane Library 1997 Issue 4.
(Type V evidence - expert opinion; The two randomised controlled trials reviewed were both excluded because of methodological shortcomings)
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14.2 IN LABOUR  
The Statements The Evidence
14.2a. There is no dispute regarding the value of fetal surveillance to identify distress in labour. Auscultation of the fetal heart during, and immediately following, contractions has been conventionally used to identify changes indicative of imminent hypoxia (i).
(Health gain notation - 1 "beneficial")
i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 846-882
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 208-209);
14.2b. The passage of thick meconium is associated with an increased risk of fetal and neonatal mortality (thick meconium at onset of labour carries a 5-7 times increased risk of perinatal death)(i). i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 847-848
(Type IV evidence - observational studies. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. p. 208)
14.2c. Electronic fetal heart monitoring by electocardiography provides the most reliable method of monitoring the fetal heart in labour by identification of changes in base rate, decelerations and loss of baseline variability(i).
(Health gain notation - 3 "trade-off between beneficial and adverse effects")
caveat: Continuous electronic monitoring, while reassuring for many women creates anxiety for others, and limits activity in labour (see statement ‘o’).
i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 846-878
(Type I evidence - systematic review. Summary in Enkin M, Keirse MJNC, Renfrew M, Neilson J. A guide to effective care in pregnancy and childbirth. 2nd ed. Oxford: Oxford University Press. 1995. pp. 210-214)
14.2d. The use of continuous electronic monitoring versus auscultation, especially without the capacity to measure fetal pH increases the use of Caesarean section (relative risk = 1.33) and operative vaginal deliveries (relative risk = 1.23)(i).
(Health gain notation - 3 "trade-off between beneficial and adverse effects")
caveat: The increase in Caesarean section is not associated with a reduction in mortality (provided there is equal emphasis on recognition and action in the presence of fetal heart abnormality) although a decrease in Apgar scores of <4 at 1 minute and neonatal seizures has been demonstrated(ii).
i. McDonald D, Grant A, Sheridan-Pereira M, Boylan P, Chalmers I. The Dublin randomised controlled trial of intrapartum fetal heart rate monitoring. American Journal of Obstetrics and Gynecology. 1985; 152(5): 524-539
(Type II evidence - randomised controlled trial of 12,964 women);
ii. Thacker SB, Stroup DF, Peterson HB. Continuous electronic fetal heart monitoring during labour. Cochrane Database of Systematic Reviews. Cochrane Library. 1997 Issue 4.
(Type I evidence - systematic review)
14.2e. Current consensus is to limit continuous electronic fetal heart monitoring to high risk cases, including those with interventions (induction, agumentation or epidural analgesia), and use either intermittent auscultation or electronic monitoring for those with neither signs nor risk of compromise. Further trials are needed for both low and high risk groups(i,ii,iii).

(Health gain notation - 3 "trade-off between beneficial and adverse effects")

i. Thacker SB, Stroup DF, Peterson HB. Continuous electronic fetal heart monitoring during labour. Cochrane Database of Systematic Reviews. Cochrane Library. 1997 Issue 4.
(Type I evidence - systematic review);
ii. Spencer JAD, Ward RHT, (eds.). Intrapartum fetal surveillance. Recommendations arising from the 26th RCOG Study Group. London: Royal College of Obstetricians and Gynaecologists, 1993
(Type V evidence - expert opinion)
iii. MIDIRS. Fetal heart rate monitoring. Leaflet No. 2 MIDIRS, January 1996
(Type V evidence - expert opinion)
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Health Evidence Bulletins: Wales, Duthie Library, UWCM, Cardiff CF14 4XN. e-mail: weightmanal@cardiff.ac.uk