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Preconception care lowers risk of abnormalities in infants of diabetics

 

Infants of women with diabetes mellitus are at increased risk for congenital anomalies. This meta-analysis aims to assess the effect of preconception care in reducing abnormalities in infants of women with pregestational diabetes.

Bottom line

Preconception care is associated with a lower risk of abnormalities in infants of mothers with pregestational diabetes.

Reference

JG Ray et al. Preconception care and the risk of congenital anomalies in the offspring of women with diabetes mellitus: a meta-analysis. Quarterly Journal of Medicine 2001 94: 435-444.

Search

The literature was searched using MEDLINE (1970 to 2000) and Embase (1980 to 2000). References from identified papers and review articles were also examined. To be included, studies had to compare women with pregestational diabetes receiving preconception care with diabetic women not receiving care until after conception.

Sixteen cohort studies (eight retrospective and eight prospective) were identified. Most study participants had type 1 diabetes; three studies also included women with type 2 diabetes. Ages ranged from 21 to 29 years.

The preconception care differed between studies, for example in terms of contraceptive, dietary and insulin advice. For non-recipients, the gestational period at which they were eligible for post-conception care varied and only half of the studies defined the type of care they received. Similarly, only half of the studies described the method used to assess abnormalities, which was by physical examination.

Fourteen studies assessed major congenital abnormalities in 2,651 infants (1,192 from mothers having received preconception care and 1,459 from non-recipients). Nine studies assessed both major and minor abnormalities in 2,104 infants (896 from recipients and 1,208 from non-recipients).

Results

Women who received preconception care were, on average, nearly two years older than non-recipients and less likely to be smokers (19.6% versus 30.2% in four studies reporting smoking status).

The average first trimester glycosylated haemoglobin levels were lower among recipients of preconception care than non-recipients (difference of 2.3%, 95% confidence interval 2.1 to 2.4; 7 studies).

The risk for major abnormalities was lower among recipients than non-recipients (relative risk 0.36, 95% confidence interval 0.22 to 0.59). The rate of anomalies was 2.1% versus 6.5%.

The risk for major and minor abnormalities was also lower among recipients than non-recipients (relative risk 0.32, 95% confidence interval 0.17 to 0.59). The rate of anomalies was 2.4% versus 7.7%.

When the eight prospective studies were analysed separately, the risk for major abnormalities remained significantly lower among recipients than non-recipients (relative risk 0.42, 95% confidence interval 0.24 to 0.74).

Comment

Preconception care was found to be associated with a lower risk of major and minor abnormalities among infants of diabetic women (supported by the lower first-trimester glycosylated haemoglobin levels observed in women receiving it). The extent to which this care reduces such abnormalities is difficult to determine due to limitations of the studies contributing to this analysis. For example, some of the congenital abnormalities observed may have been attributable to other factors unrelated to diabetes, such as lifestyle behaviours or genetics, neither of which were assessed.

This paper also demonstrates that many diabetic women do not receive preconception care, highlighting the need to ensure that they do receive appropriate counselling and reach optimum diabetic control before they conceive. For example, visits by appropriately aged diabetic women to a health professional could also be used to check on their future pregnancy plans and increase their awareness of the importance of care prior to conception.

The differences in care between the studies precludes suggesting the optimum preconception care for diabetic women, but would include the adjustment of insulin treatment, glycaemic control, as well as advice on pregnancy planning and contraceptive use, diet and folic acid supplementation.