[Diabetes, pregnancy and birth defects]

Diabetes mellitus affects 3 to 10% of pregnant women. The reported frequency of congenital malformations (CM) in diabetic mothers is 5.5 to 10%, contributing these defects to approximately 40% of the neonatal mortality in children of diabetic mothers (CDM).

To investigate the frequency and type of congenital malformations in a sample of livebirths of diabetic mothers from the Mexican population.

The analyzed information was obtained from the RYVEMCE (Registro y Vigilancia Epidemiológica de Malformaciones Congénitas). We analysed the type and frequency of the different CM diagnosed. These frequencies were compared with the whole amount of those CM included in the database of our registry (20,381). As part of the analysis, other maternal and neonatal variables were also compared between CDM and the control group.

A total of 314 CDM (0.77%), 234 malformed and 80 non malformed were identified. The frequencies of cleft palate (CP), limb reduction defect (LRD) and microcephaly (MIC) were significantly higher in CDM than in the rest of malformed newborns of not diabetic mothers of the RYVEMCE (OR: 9.9, 3.8 and 10.0, respectively). A higher frequency of macrosomia was observed in CDM (18.0%) than in controls (6.1%), OR: 3.4, p < 0.001, in the frequency of preterm birth (28.5% than controls 13.0%), OR: 3.02, p < 0.0001 and in caesarean delivery (71.5% than controls 44.4%) OR: 3.15, p < 0.00001.

Our results confirm the higher frequency of CM in CDM and in particular a higher risk for CP, LRD and MIC. Pregnancy and delivery complications such as macrosomia and preterm and caesarean delivery were also more frequent in CDM that controls. Certain associations of CM not described previously, were observed in the studied sample. Our results confirm the need of pregnancy planning including a pre-gestational and gestational control of maternal glycaemia, particularly in a population with such a high prevalence of diabetes mellitus as the observed in the Mexican one.