Outcomes of pregnancies in women with type I diabetes in Scotland: a national population-based study

Objective To determine the outcomes of pregnancies in women with pre-existing, type 1 diabetes. Design Prospective, population-based cohort. Setting Scotland. Population All 273 women with type 1 diabetes with a pregnancy ending (in miscarriage, abortion or delivery) during the 12 months (from April 1, 1998 to March 31, 1999). Methods Pregnancies identified prospectively by clinicians in each hospital; outcome data collected from case records and from Scottish national data sets. Main outcome measures Perinatal and infant mortality, congenital anomaly and birthweight. Results Of the 273 pregnancies, 40 (14.7%) ended in miscarriage, 20 (7.3%) in abortion and 213 (78%) in delivery. Three deliveries were twin births, thus 216 babies were born. Stillbirth rate (4/216): 18.5 (95% Cl 5.1-46.8) per 1000 total births; perinatal mortality rate (6/216): 27.8 (95% Cl 10.2-59.4) per 1000 births. There were 13 verified congenital anomalies (in six abortions and seven live births), anomaly rate: 60 (95% Cl 32-101) per 1000 total births. Among 208 singleton, live born infants, the mean birthweight was 3427 g. Standardised birthweight scores, relative to a reference population, showed a unimodal distribution, shifted to the right (mean, 1.57 SD). Conclusions In an unselected population, adverse outcomes remain more common among the infants of mothers with type I diabetes than in the general population. The targets of the St Vincent Declaration of 1989 have not been met. Improvements may be gained by increases in provision of prepregnancy care and in the proportion of pregnancies that are planned. However, further research is needed to clarify the root causes of adverse outcomes in the pregnancies of women with diabetes.