This is the current release of the guideline.

The quality of evidence (I-III) and classification of recommendations (A-E, I) are defined at the end of the "Major Recommendations."

Pathophysiology

1. Experimental studies suggest that hyperglycemia is the major teratogen in diabetic pregnancies, but other diabetes-related factors may also affect fetal outcomes. Further research using animal models is required to clarify the teratogenic factors associated with pre-existing and gestational diabetes. (II-3C)

Pre-Existing Diabetes

2. Prospective and retrospective cohort studies have demonstrated an increased risk of congenital abnormalities with pre-existing diabetes (see Table 2 in the original guideline document for specific malformations). Further studies that include outcomes from first and second trimester pregnancy terminations, account for potential confounding variables, and use appropriate control groups are required. (II-2A)

Gestational Diabetes

3. Prospective and retrospective cohort studies have demonstrated an increased risk of congenital abnormalities with gestational diabetes. This observation is probably related to the inclusion of women with unrecognized type 2 diabetes. Clarification of the relationship between gestational diabetes and congenital abnormalities by studies that include outcomes from first and second trimester pregnancy terminations, account for potential confounding variables, and use appropriate control groups are required. (II-2A)
4. In some women, type 2 diabetes may be identified for the first time in pregnancy. Pre-conception recognition of women at high risk for type 2 diabetes and optimal glycemic control may reduce the risk of congenital anomalies. (II-2A)

Medications

5. Second generation sulfonylureas have not been associated with congenital abnormalities in human studies. The use of biguanides may be associated with other adverse perinatal outcomes. The use of other oral antihyperglycemic agents is not recommended in pregnancy. (II-2A)

Effect of Obesity

6. The risk of congenital abnormalities is increased in the offspring of obese women with diabetes. A healthy diet and regular exercise may help optimize pre-pregnancy weight and reduce the risk of congenital anomalies. (II-2A)

Prenatal Diagnosis

7. Accurate determination of gestational age is required in women with diabetes. Given the increased risk of congenital abnormalities, they should be offered appropriate biochemical and ultrasonographic screening and a detailed evaluation of fetal cardiac structures. (II-2A)

Pre-Conception Counseling

8. Women with diabetes should be offered pre-conception counselling with a multidisciplinary team to optimize general health and glycemic control and to review the risks of congenital anomalies. (II-2A)
9. A careful history should be obtained to identify other factors, such as a positive family history or advanced maternal age, that may further increase the risk of congenital structural or chromosomal abnormalities. (II-2A)
10. Pregnancy in women with diabetes should be planned. Good contraceptive advice and pre-pregnancy counselling are essential. Euglycemia should be maintained before and during pregnancy. (II-2A)
11. All women with diabetes should be counselled regarding intake of foods high in folic acid, folate-fortified foods, and appropriate folic acid supplementation of 4 to 5 mg per day pre-conceptionally and in the first 12 weeks of gestation. (II-2A)
12. A substantial number of women with diabetes do not access pre-conception care programs. Strategies are needed to improve access to such programs and to maximize interventions associated with improved pregnancy outcomes, such as folic acid use. (II-2A)

Definitions

Quality of Evidence Assessment*

I: Evidence obtained from at least one properly designed randomized controlled trial.

II-1: Evidence obtained from well-designed controlled trials without randomization.

II-2: Evidence obtained from well-designed cohort (prospective or retrospective) or case–control analytic studies, preferably from more than one center or research group.

II-3: Evidence obtained from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments (such as the results of treatment with penicillin in the 1940s) could also be included in this category

III: Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

Classification of Recommendations **

A.   There is good evidence to recommend the clinical preventive action

B.   There is fair evidence to recommend the clinical preventive action

C.   The existing evidence is conflicting and does not allow to make a recommendation for or against use of the clinical preventive action; however, other factors may influence decision-making

D.   There is fair evidence to recommend against the clinical preventive action

E.   There is good evidence to recommend against the clinical preventive action

I.   There is insufficient evidence (in quantity or quality) to make a recommendation; however, other factors may influence decision-making

*The quality of evidence reported in these guidelines has been adapted from The Evaluation of Evidence criteria described in the Canadian Task Force on Preventive Health Care.

**Recommendations included in these guidelines have been adapted from the Classification of Recommendations criteria described in the Canadian Task Force on Preventive Health Care.

None provided

The type of supporting evidence is identified and graded for each recommendation (see "Major Recommendations").

Not applicable: The guideline was not adapted from another source.

2007 Nov

Society of Obstetricians and Gynaecologists of Canada - Medical Specialty Society

Society of Obstetricians and Gynaecologists of Canada

Society of Obstetricians and Gynaecologists of Canada Genetics Committee
Society of Obstetricians and Gynaecologists of Canada Maternal Fetal Medicine Committee

Principal Authors: Victoria M. Allen, MD, MSc, FRCSC, Halifax NS; B. Anthony Armson, MD, MSc, FRCSC, Halifax NS

Genetics Committee Members: R. Douglas Wilson (Chair), MD, MSc, FRCSC, Philadelphia PA; Victoria M. Allen, MD, MSc, FRCSC, Halifax NS; Claire Blight, RN, Halifax, NS; Alain Gagnon, MD, FRCSC, Vancouver B.C.; Jo-Ann Johnson, MD, FRCSC, Calgary AB; Sylvie Langlois, MD, FRCPC, Vancouver B.C.; Anne Summers, MD, FRCPC, Toronto ON; Philip Wyatt, MD, PhD, North York ON

Maternal Fetal Medicine Committee Members: Dan Farine (Chair), MD, FRCSC, Toronto ON; B. Anthony Armson, MD, MSc, FRCSC, Halifax NS; Joan Crane, MD, FRCSC, St. John's NL; Marie-France Delisle, MD, FRCSC, Vancouver B.C.; Lisa Keenan-Lindsay, RN, Toronto ON; Valerie Morin, MD, FRCSC, Montreal QC; Carol Ellison Schneider, MD, FRCSC, Winnipeg MB; John Van Aerde, MD, FRCPC, Edmonton AB

Not stated

This is the current release of the guideline.

None available

None available

This NGC summary was completed by ECRI Institute on March 9, 2009. The information was verified by the guideline developer on March 25, 2009.

This NGC summary is based on the original guideline, which is subject to the guideline developer's copyright restrictions.