Diabetes in Pregnancy -1 - Overview of an Epidemic
Diabetes mellitus is a group of conditions characterized by elevated levels of blood glucose (sugar) that results from inadequate amounts of insulin production, defects in insulin action (e.g., ‘resistance’ to its action), or both. Despite the advances that have been made in the management of diabetes over the years, we are now confronting a worldwide epidemic of diabetes that is being promulgated by the comparably worldwide epidemic of obesity. The World Health Organization has estimated that, barring some remarkable changes in lifestyle, eating, and exercise habits, over the next 20 years there will be a 35% increase in the prevalence of diabetes. To put the magnitude of this problem in perspective, according to International Diabetes Federation statistics, in 1985, an estimated 30 million people worldwide had diabetes; in 2000, a little over a decade later, the figure had risen to over 150 million; by 2025, the figure is expected to rise to 380 million. Quite frankly, that may well be a conservative estimate.
In the U.S. between 1980 and 2005, the number of individuals diagnosed with diabetes increased from 5.6 million to 15.8 million. That reflects an increase in crude prevalence of 120% over that time period. Today, 5-6% of all Americans know they have diabetes and it is estimated that one-third or more of individuals who have the condition, currently do not even know it. Although we generally attribute a large percentage of the increase in prevalence of diabetes to the aging population, the mean age of onset of disease is falling and many young women in the child-bearing years are at increased risk for developing diabetes in pregnancy or for having undiagnosed ‘pregestational’ before they conceive. The dangers of this will be addressed later. In the state of South Carolina where I work, more than 8% of the population has documented disease. The condition is more common in Black women and they tend to develop it at younger ages. Diabetes also appears to be rapidly increasing in the rapidly expanding Hispanic population.
Overall, nearly 5% of pregnancies are complicated by diabetes. Ninety percent of these women will have ‘gestational’ diabetes that is not present early in the pregnancy, but develops by late second or early third trimester. Reasons for this will be discussed later as well. Routine screening for diabetes in pregnancy is a ‘standard of care’ and detects 85-90% women with the condition by 28 weeks gestation. Whether pregestational or gestational, diabetes is associated with increased risks for both fetal and maternal morbidity. Although the risks can be reduced almost to that of the nondiabetic population by good control of blood glucose levels, many pregnant women are unable or unwilling to devote the time and effort necessary to achieve that control and, even more sadly, many providers are also either unable, unwilling, or do not have the time or resources it takes to provide the educational support and ongoing care necessary to optimize pregnancy outcome.
In the next several posts, we will focus our discussion on insulin and its action, the physiological changes that occur during pregnancy that help to ‘bring out’ the disease, and on ‘gestational diabetes’ and its diagnosis and management.