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Table 2 Characteristics of included retrospective cohort studies

From: Pre-pregnancy care for women with pre-gestational diabetes mellitus: a systematic review and meta-analysis

Study/ Year of Publication Reference (country) Participants Intervention Outcome Risk of Bias
Dunne 1999 [14] (UK) 47women with IDDM 12 of them attended pre-pregnancy care clinic and 35 women did not. PPC included assessment of diabetes complications and glycemic control The PPC group had significantly lower level of HA1C level compared to the NPPC group (p < 0.008). Medium (Due to the audit nature of the report there is no clear description of the intervention, some important confounders were not addressed such as White’s classification and the outcome assessment was not blinded)
There were no congenital malformations in both groups.
Damm 1989 [13] (Denmark) 197 attended PPC and 61 didn’t attend PPC included: contraception and glycemic control. The rate of congenital malformations was significantly lower in the PPC group 1.0% than the NPPC group 8.2%, (p < 0.01). No significant difference in the level of HA1C during the first trimester between the two group High (unclear description of the participants, the intervention and the outcome, the data of the pre-pregnancy care were a subset of from different periods of the study)
Goldman 1986 [19] (Israel) 44 women with type I diabetes attended the pre-pregnancy clinic and 31women with type I diabetes did not attend PPC included assessment of diabetic complications, Contraception advice, Glycemic control and dietary advice The NPPC group had 3 infants with congenital abnormalities while the PPC did have any infant with congenital abnormalities Low (Clear description of participants and intervention, noted confounding factors and well presented results. There was significant difference between the two groups in the diabetes complications before intervention)
Fuhrmann 1986 [17]& 1984 [16]& 1983 [15] (Germany) 620 pregnant women with insulin dependent diabetes,183 received pre-pregnancy care 437 women did not PPC included: short hospitalization every 3 month until conception, education, self monitoring of blood glucose, assessment and treatment of diabetes complications and glycemic control PPC group had significantly lower rate of congenital malformations 1.1% compared to the NPPC group 7.0% (p < 0.01) Medium (Well described intervention, no blinding for the outcome, no description of the possible confounding factors)
Rowe 1987 [25] (UK) 21 IDDM 14 received pre-pregnancy care and 7 did not PPC included The PPC group had significantly better initial HA1C level (p <0.0001). High (Unclear description of the participants, no description of possible confounding factors, no blinding in assessment of the outcome, small group, high target of HbA1C 5-9%)
glycemic control, counseling and blood glucose self monitoring
Steel 1990 [26] & 1982 [29] (UK- Scotland) 143 IDDM women attended the pre-pregnancy care clinic and 96 IDDM women did not attend PPC included: education, glycemic controlled and contraception PPC group had lower first trimester HbA1C as compared to NPPC group (p < 0.0001) and lower rate of congenital malformations (p < 0. 005), maternal hypoglycemia was significantly common in the PPC group than the NPPC (p < 0. 001) Medium (Good description of interventions, contamination of the control who might know about the usefulness of the and the outcome assessment was not blinded)
  1. Key: HbA1C = Glycosylated Hemoglobin A, PPC = Pre-pregnancy Care, NPPC = No Pre-pregnancy Care, OR = Odd Ratio, IDDM = Insulin depended Diabetes Miletus.