1






Background

  
 

1.1

  

Introduction

Diabetes is a common medical disorder complicating pregnancy, affecting approximately one pregnant woman in 250 in the United Kingdom (UK). There are two major types of diabetes. Type 1 diabetes occurs because the insulin-producing cells of the pancreas have been destroyed by the body's immune system and typically develops in children and young adults. Type 2 diabetes is more commonly diagnosed in adults over the age of 40 years, although, increasingly, it is appearing in young people.1 In this condition, insulin is produced but is insufficient for the body's needs. There is also a degree of insulin resistance, where the cells in the body are not able to respond to the insulin that is produced. In England, about 85% of the diabetic population has type 2 diabetes but type 1 diabetes is more frequent in pregnancy.2

Diabetes is becoming more common. Type 1 diabetes is increasing in children, mainly in those under the age of five.2 Type 2 diabetes is increasing in all age groups, including children and young people, but predominantly among the Black, Asian and Other ethnic minority groups.2 This lifelong disease impacts on lifestyle, health and wellbeing.

Women with diabetes are at an increased risk of losing a baby during pregnancy, having a baby with a congenital anomaly or the baby dying during the first year of life. These risks were measured in the mid 1990s by a number of regional studies in the UK. They found a three- to five-fold increase in the perinatal mortality rate and a four- to ten-fold increase in the congenital malformation rate compared with that of the general population.3–6 This was disappointing in light of the St. Vincent Declaration in 1989, which set a 5-year target to achieve similar pregnancy outcomes in women with diabetes to those without the condition.6,7 A confidential enquiry review of a sample of pregnancies in England, Wales and Northern Ireland, conducted in 1997, also identified a substantial proportion of mothers with diabetes whose babies had died who received suboptimal care.8

Responding to this, the Confidential Enquiry into Maternal and Child Health (CEMACH) initiated a national enquiry programme aimed at improving the quality of maternity care and pregnancy outcomes for women with pre-gestational diabetes in England, Wales and Northern Ireland. This programme of work comprises three linked studies:

  1. A survey of maternity services for women with type 1 and type 2 diabetes in 2002.9
  2. A descriptive study on all pregnancies of women with pre-gestational diabetes who delivered or booked between 1 March 2002 and 28 February 2003, with follow up to pregnancy outcome at 28 days after delivery. This study included an audit of standards of care for women with pre-gestational diabetes.
  3. A confidential enquiry, consisting of multidisciplinary panel case reviews. This comprises a case–control study into the impact of clinical care on pregnancy outcome and an audit of care during and after pregnancy, for women with pre-gestational diabetes.

The survey of maternity services compared service provision for women with diabetes in England, Wales and Northern Ireland in 2002 with those available 10 years previously.9 While improvements in the provision of specialist staff were found, there were three main areas of concern: nearly one-third of units did not provide multidisciplinary clinics; an equivalent proportion of units routinely admitted the baby of a mother with diabetes to the neonatal unit without a specific medical indication; and there appeared to be poor provision of prepregnancy care, with little development in this area over 10 years.

This report describes the findings from the second study; that is, the descriptive study, in CEMACH's diabetes programme of work. This study had two principal aims:

  1. To provide national outcome rates for babies of women with pre-existing diabetes, as outlined below:
    1. perinatal mortality rates
    2. stillbirth rates
    3. neonatal mortality rates
    4. congenital anomaly rates.
  2. To assess the degree to which clinical standards of care were met for women with pre-gestational diabetes and their babies from preconception to the postnatal period.
  
 

1.2

  

Methods

  
 

1.2.1

  

Data collection

Pre-gestational diabetes was defined as either type 1 or type 2 diabetes that had been diagnosed at least 1 year before the woman's estimated delivery date (EDD). Data were collected on women at any stage (from booking to delivery) between 1 March 2002 and 28 February 2003 and followed through to outcome of baby at 28 days.

All maternity units in England, Wales and North Ireland expecting to provide some aspect of diabetes maternity care in 2002–03 were provided with information leaflets, notification forms and questionnaires. There were 231 maternity units recorded as providing some form of maternity care to women with diabetes in this period.

Information leaflets were given to all women with pre-gestational diabetes prior to the data collection. The notification forms were sent to CEMACH regional offices upon the identification of a pregnant woman as having pre-gestational diabetes. An additional questionnaire was subsequently filled in either concurrent to the pregnancy or retrospectively based on medical records. The questionnaire was completed by health professionals at the unit attended by the pregnant women. The questionnaire included demographic characteristics, type of diabetes, labour, delivery and outcome details up to day 28 for the baby, and a number of additional questions relating to care from prepregnancy to the neonatal period (see Appendix A). The data collection was co-ordinated, validated and entered on to a centralised database at a regional level.

During the study, 3761 women were notified to CEMACH and accounted for 3836 pregnancies. Within this group, there were 28 women for whom the type of diabetes was either maturity onset diabetes of the young (11) or other/unknown (17). These 28 pregnancies have been excluded in all descriptions and analyses throughout this report. This report is therefore based on 3808 pregnancies in 3733 women who had type 1 or type 2 diabetes prior to pregnancy and booked or delivered between 1 March 2002 and 28 February 2003 (Table 1.1).

Not included in the programme were women who actively requested for their data not to be included, those who did not seek medical attention during pregnancy and those women who were not reported to the enquiry by the health professionals caring for them during pregnancy.

As this study was part of a national clinical audit, ethical approval and consent were not specifically sought at the outset of the project. In 2001, Section 60 of the Health and Social Care Act was introduced to allow organisations to obtain patient-identifiable information for medical purposes in circumstances where it was impracticable to obtain informed consent from the patients concerned. CEMACH received Section 60 approval for its programme of work in December 2003.

  
 

1.2.2

  

Congenital anomalies and perinatal mortality

Congenital anomalies

Data were collected on presumed congenital anomalies in the antenatal period and up to 28 days of life for all live births, all fetal losses after 20 completed weeks of gestation and all terminations of pregnancy at any gestation. Any reported diagnosis was subsequently confirmed by postmortem findings, genetic results or correspondence between health professionals. Data are presented in this report for confirmed anomalies only. These anomalies were coded according to the 10th revision of the International Classification of Diseases (ICD10). Individual codes were grouped according to the classification system used by the European Surveillance of Congenital Anomalies (EUROCAT) and can be seen in Appendix B.10 Minor congenital anomalies were excluded, a list of which is provided in Appendix C. Where information was limited, coding was validated by an independent paediatrician.

Perinatal mortality

Stillbirth was defined as an in utero loss delivering after 24 completed weeks of gestation, neonatal death as the death of a live birth (born at any gestation) up to 28 days after birth and perinatal death as a stillbirth or death of a live birth (born at any gestation) up to 7 days after birth.

Perinatal mortality rates are based on the births between 1 March 2002 and 28 February 2003, as opposed to the entire study sample. This therefore excludes births to women booking at or before 28 February 2003 but delivering after this date (Table 1.1). This approach, using deliveries in 1 calendar year, allows direct comparisons with other reported national perinatal mortality rates.

  
 

1.2.3

  

Audit of standards of care

The standards of care for Chapters 6 and 9 in this report (Appendix D) were drawn up at the outset of the study by a multidisciplinary professional group of senior clinicians with expertise in diabetic pregnancy (the Diabetes Multidisciplinary Resource Group). The standards were derived from the most contemporary UK-based national guideline for the management of diabetes in pregnancy available, the Scottish Intercollegiate Guidelines Network (SIGN) guideline No. 9.11 This was subsequently updated in November 2001.12 The National Service Framework (NSF) for Diabetes standards were published in December 2001, which is the current guideline used for the National Health Service (NHS) in England.2 There is good agreement between all the guidelines.

The assessment of clinical care in this audit was based on information contained in the questionnaire filled in by the health professionals (see 1.2.1). This questionnaire contained a number of free-text fields which collected information on ‘reasons for’ or ‘indications for’ certain events occurring during pregnancy and the neonatal period. This free-text information was subsequently categorised by an individual clinician (obstetrician and paediatrician, as appropriate) for the purposes of exploring the data further.

  
 

1.3

  

Limitations

Some important maternal and neonatal outcomes were not covered in the data collection, in particular renal function and hypoglycaemic episodes of the mother and hypoglycaemic episodes in the newborn. In addition, certain confounding factors for adverse maternal and neonatal outcome were not collected including body mass index, socioeconomic status and smoking. There are thus some limitations with conclusions that can be drawn regarding the associations between certain risk factors and outcomes.

Tables where free-text information has been categorised, as detailed above in section 1.2.3, are footnoted throughout the report. Categorisation was based purely on text contained in the questionnaire, with no additional information collected directly from case notes. Results contained within these tables should therefore be interpreted with a degree of caution.

  
     

References

  1. Hotu S, Carter B, Watson PD, Cutfield WS, Cundy T. Increasing prevalence of type 2 diabetes in adolescents. J Paediatr Child Health 2004;40(4):201–4.
  2. Department of Health. National Service Framework for Diabetes (England) Standards. London: The Stationery Office; 2001 [www.dh.gov.uk/PublicationsAndStatistics/Publications/PublicationsPolicyAndGuidance/PublicationsPolicyAndGuidanceArticle/fs/en?CONTENT_ID=4002951&chk=09Kkz1].
  3. Casson IF, Clarke CA, Howard CV, McKendrick O, Pennycook S, Pharoah PO, et al. Outcomes of pregnancy in insulin dependent diabetic women: results of a five year population cohort study. BMJ 1997;315:275–8.
  4. Hawthorne G, Robson S, Ryall EA, Sen D, Roberts SH, Ward Platt MP. Prospective population based survey of outcome of pregnancy in diabetic women: results of the Northern Diabetic Pregnancy Audit, 1994. BMJ 1997;315:279–81.
  5. Penney GC, Mair G, Pearson DW; Scottish Diabetes in Pregnancy Group. Outcomes of pregnancy in women with type 1 diabetes in Scotland: a national population-based study. BJOG 2003;110:315–18.
  6. Hadden DR, Alexander A, McCance DR, Traub AI, Northern Ireland Diabetes Group, Ulster Obstetrical Society. Obstetric and diabetic care for pregnancy in diabetic women: 10 years outcome analysis, 1985–1995. Diabet Med 2001;18:546–53.
  7. Diabetes Care and Research in Europe: The Saint Vincent Declaration. Diabet Med 1990:7;360.
  8. Confidential Enquiry into Stillbirths and Deaths in Infancy. 6th Annual Report. London: Maternal and Child Health Research Consortium; 1999.
  9. Confidential Enquiry into Maternal and Child Health. Maternity Services in 2002 for Women with Type 1 and Type 2 Diabetes, England, Wales and Northern Ireland. London; RCOG Press; 2004.
  10. European Registration of Congenital Anomalies. EUROCAT Report 8: Surveillance of Congenital Anomalies in Europe 1980–1999. Belfast: University of Ulster; 2002.
  11. Scottish Intercollegiate Guidelines Network. Management of Diabetes in Pregnancy. SIGN Publication No. 9. Edinburgh: SIGN (no longer available).
  12. Scottish Intercollegiate Guidelines Network. Management of Diabetes. SIGN Publication No. 55. Edinburgh: SIGN; 2001 [www.sign.ac.uk/guidelines/fulltext/55/index.html].