MATERNAL AND EARLY CHILD HEALTH

Health Evidence Bulletins - Wales

Date of Completion: 27.10.97

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


3. Medical disorders in pregnancy

The disorders covered in this chapter reflect the coverage of the original Protocol. Other disorders, including those relating to circulatory and respiratory conditions, will be considered for inclusion in any future updates.

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

3.1 DIABETES: Pre-existing
The Statements The Evidence  
3.1a. The following management strategies are recognised good practice for women with diabetes(i,ii).

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

  • Prepregnancy counselling by those who care for diabetic women;
  • Coordinated specialist care from very early pregnancy;
  • Home instead of hospital glucose monitoring;
  • Ultrasound surveillance for fetal growth, fetal abnormality and dating;
  • Allowing pregnancy to continue to term in otherwise uncomplicated diabetic pregnancies;
  • Careful attention to insulin requirements postpartum;
  • Encouraging diabetic women to breastfeed.

Current practice in the UK is well summarised in a report by the Pregnancy and Neonatal Care Group(ii).

i. Chalmers I, Enkin M, Keirse MJNC. Chapter 36 in Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989
(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. pp. 126-134);
ii. Jardine Brown C, Dawson A, Dodds R, et al. Report of the Pregnancy and Neonatal Care Group. Diabetic Medicine. 1996: 13: S43-S53

(Type V evidence - expert opinion)

 

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3.1b. Tight as opposed to too tight or moderate control of blood sugar levels during pregnancy (aiming for levels between 5.6 and 6.7 mmol/litre) is likely to be beneficial(i)

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

i. Walkinshaw SA. Very tight versus tight control of diabetes in pregnancy. Cochrane database of systematic reviews. Cochrane Library 1997 Issue 4.
(Type II evidence - review of two trials of 197 women in total, with slightly different methodologies [method of randomisation not stated for either trial])
3.1c. There is a trade off between beneficial and adverse effects in the use of corticosteroids to promote fetal maturation before preterm delivery and these should be used with great caution in diabetic women(i)

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

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 p. 759
(Type II evidence - randomised controlled trials with 35 women only. 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. 177)
3.1d. Because of the increased risk of maternal and perinatal complications, most pregnant women with diabetes are subjected to serial fetal assessment. No randomised trials have yet been carried out to identify which regime for fetal assessment is the most effective(i)i.
(Health gain notation - 4 also Chapter "unknown"; See 15: Suspected fetal compromise in pregnancy and labour)
i. 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.131

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3.1e. Review suggests that the following strategies are unlikely to be beneficial for women with diabetes(i)

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

  • Elective delivery before term in women with otherwise uncomplicated diabetes
  • Elective caesarean section for pregnant women with diabetes and otherwise uncomplicated pregnancy;
  • Discouraging breastfeeding in women with diabetes;
  • Prohibition of low dose oral contraceptives for diabetic women;
i. Chalmers I, Enkin M, Keirse MJNC. Chapter 36 in Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989
(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. pp. 126-133)
3.1f. Betamimetics for preterm labour in women with diabetes, especially if combined with corticosteroids, carry a high risk of deregulation of diabetic control and should be avoided(i)i.

(Health gain notation - 6 "likely to be harmful")

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 p. 711
(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. 166)
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3.2 GESTATIONAL DIABETES  
Much has been achieved in improving care for diabetic women. There remains a need, both for well-designed trials and better survey data, to include all pregnant women, not just those attending specialist centres (i).
 
i. 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. 133.
(Type V evidence - expert opinion)
 
The term ‘gestational diabetes’ previously referred to ‘carbohydrate intolerance’ diagnosed during pregnancy which subsequently resolved. The term has been updated to include ‘disturbance of carbohydrate metabolism of variable severity with onset or first recognition in pregnancy’ - thus including IDDM and NIDDM diagnosed for the first time in pregnancy in addition to impaired carbohydrate tolerance. Uncertainty still surrounds this subject despite enormous scientific and clinical investigation(i,ii,iii).
 
i. Metzger BE and the organizing committee. Summary and recommendations of the third international workshop-conference on gestational diabetes mellitus. Diabetes. 1991; 40(suppl.2):197-201
(Type V evidence - expert opinion);
ii. Fraser R. Diabetes in pregnancy. Archives of disease in childhood. 1994; 71:F224-F23
(Type V evidence - expert opinion);
iii. Jardine Brown C, Dawson A, Dodds R, et al. Report of the Pregnancy and Neonatal Care Group. Diabetic Medicine. 1996: 13: S43-S53
(Type V evidence - expert opinion)
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The Statements The Evidence
3.2a. Routine population screening for ‘gestational diabetes’ by:

glucose challenge test or measurement of blood glucose during pregnancy is unlikely to be beneficial (i):
(Health gain notation - 5 "unlikely to be beneficial")

caveat: Timed random laboratory blood glucose measurements in individual cases may be beneficial(ii). Further research is indicated to determine which women should be tested.

i. Chalmers I, Enkin M, Keirse MJNC. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989 pp. 403-409
(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. pp. 58-59);
ii. Jardine Brown C, Dawson A, Dodds R, et al. Report of the Pregnancy and Neonatal Care Group. Diabetic Medicine. 1996: 13: S43-S53
(Type V evidence - expert opinion)

 

3.2b. There appears to be no benefit in the use of insulin or dietary regulation for women with simple glucose intolerance and such strategies should only be advocated in the context of randomised controlled trials(i). Treating gestational diabetes by insulin or dietary regulation to reduce blood sugar does reduce fetal weight but there is no evidence regarding the consequences of fetal macrosomia (fractures or persistent neurological damage).
(Health gain notation - 5 "unlikely to be beneficial")
i. Walkinshaw SA. Dietary regulation for ‘gestational diabetes’. Cochrane database of systematic review. Cochrane Library 1997 Issue 4.

(Type I evidence - systematic review)

3.2c. Where gestational diabetes is treated, the results from one trial suggest that postprandial versus preprandial blood glucose monitoring is beneficial in terms of glycaemic control and neonatal outcomes (NNT = 3, for birth size within limit for normal gestational age)(i).
(Health gain notation - 2 "likely to be beneficial" but see statement 3.1.1b). 
i. de Veciana M, Major CA, Morgan MA et al. Postprandial versus preprandial blood glucose monitoring in women with gestational diabetes mellitus requiring insulin therapy. New England Journal of Medicine. 1995; 333:1237-41
(Type II evidence - small randomised controlled trial of 66 women) 
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3.3 EPILEPSY  
The Statements The Evidence
3.3a. Expert reviews suggest the following management strategies for women with epilepsy(i,ii):

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

  • Specialist pre-conception advice;
  • The pregnant woman with epilepsy should be treated with the lowest possible dose of a single antiepileptic and dosage should be titrated against symptoms;
  • Drug combinations should be avoided;
  • Women should be advised about the possible teratogenicity of antiepileptic drugs and the need to continue treatment
    [carbamazepine carries a 5-30% increased risk of facial dysmorphism and mental retardation and a 0.5-1% risk of neural tube defects(NTD)]; [sodium valproate carries a 1.5-2.0% risk of NTD];
  • Screening of the fetus should be offered for women on carbamazepine or sodium valproate because of the increased risk of neural tube defects;
  • Information about new anticonvulsants [gabapentin, lamotrigine, topiramate and vigabatrin] is very limited and, while they are theoretically less teratogenic from animal experiments, the risks and benefits are yet to be established;
  • Folic acid (5 mg daily) should be started before conception and continued for 12 weeks after.
i. Epilepsy and pregnancy. Drug and Therapeutics Bulletin 1994; 32(7):49-51

(Type V evidence - expert opinion);

ii. Cleland PG. Management of pre-existing disorders in pregnancy: epilepsy. Prescriber’s Journal. 1996: 36(2): 102-109

(Type V evidence - expert opinion)

 

 

 

 

 

 

 

 

 

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3.4 HAEMAGLOBINOPATHIES  
The Statements The Evidence
3.4a. All women from populations at particular risk of haemoglobinopathy should be offered antenatal (or preferably preconceptual) testing followed, if positive, by appropriate referral and management (i,ii).

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

i. Working Party of the Standing Medical Advisory Committee. Report on Sickle Cell, Thalassaemia and other Haemoglobinopathies. London: HMSO, 1993. p.38
(Type V evidence - expert opinion)
ii. Benbow A, Semple D, Maresh M, Royal College of Obstetricians and Gynaecologists Clinical Audit Unit. Effective procedures in maternity care suitable for audit. London: Royal College of Obstetricians and Gynaecologists, June 1997. pp. 15-16.
(Review of effective procedures, classified according to type of evidence)
3.4b. The basic requirements for women with significant haemaglobinopathies are to have:
  • a designated consultant obstetrician;
  • an agreed management policy concerning pain relief and transfusion;
  • regular fetal assessment; and
  • anaesthetic collaboration(i).

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

i. Working Party of the Standing Medical Advisory Committee. Report on Sickle Cell, Thalassaemia and other Haemoglobinopathies. London: HMSO, 1993 p.38
(Type V evidence - expert opinion)
3.4c. From a small study, there is a trend for fewer sickling complications in the third trimester and puerperium if women with homozygous sickle cell disease are exchange transfused from 28 weeks(i)

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

i. Howard RJ, Tuck SM, Pearson TC. Pregnancy in sickle cell disease in the UK: results of a multicentre survey of the effect of prophylactic blood transfusion on maternal and fetal outcome British Journal of Obstetrics and Gynaecology 1995; 102:947-951
(Type IV evidence - well designed non-experimental study)
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3.5 NAUSEA and HYPEREMESIS  
The Statements The Evidence
3.5a. Antihistamines are beneficial for nausea and vomiting of pregnancy if simple measures are ineffective(i)
(Health gain notation - 1 "beneficial")
caveat: These drugs have known side effects and their safety for the fetus has not been extensively studied; In addition, since the tragedy of thalidomide, many women prefer to avoid drugs during pregnancy.
i. 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 75-77.
(Type I evidence - systematic review. See p. 503 in Chalmers et al. Effective care in pregnancy and childbirth. Oxford:Oxford University Press, 1989)
3.5b. Acupuncture point stimulation may be beneficial as an antiemetic and further research is recommended(i)

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

i. Vickers AJ. Can acupuncture have specific effects on health? a systematic review of acupuncture antiemesis trials. Journal of the Royal Society of Medicine 1996; 89: 303-311
(Type I evidence - systematic review)
3.5c. Vitamin B6 acts as an antiemetic(i) but should be avoided since overdosage induces toxic effects(ii).

(Health gain notation - 6 "likely to be harmful")

i. Jewell D, Young G. Treatments for nausea and vomiting in early pregnancy. Cochrane database of systematic reviews. Cochrane Library 1997, Issue 4
(Type I evidence - systematic review)
ii. British National Formulary, September 1996. p.399
(Type V evidence - expert opinion)
3.5d. The value of ginger for nausea and vomiting of pregnancy is unknown(i)

(Health gain notation - 4 "unknown")

i. Jewell D, Young G. Treatments for nausea and vomiting in early pregnancy. Cochrane database of systematic reviews. Cochrane Library 1997, Issue 4
(Type I evidence - systematic review)
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Health Evidence Bulletins: Wales, Duthie Library, UWCM, Cardiff CF14 4XN. e-mail: weightmanal@cardiff.ac.uk