In all populations that have been studied, however, HbA1c is normally distributed, and a value ≥6.5% is consistently at the upper tail of that distribution. In most cases, an abnormal HbA1c result reliably identifies a problem of glucose metabolism. When a patient has a medical condition that influences RBC turnover, measurement of the fasting blood glucose level helps assess the severity of a problem of glucose metabolism.
Last, obstetricians should be alert to the ADA recommendation that women who have gestational type 2 DM should be tested for persistent diabetes 6 to 12 weeks after delivery. Do not, however, measure HbA1c, which has lower sensitivity in this setting than the 2-hour glucose challenge test (which you should use).1
Interventions for newly diagnosed disease
Most professional medical associations recommend diet and exercise as first-line treatments for women in whom type 2 DM is newly diagnosed: Randomized clinical trials have demonstrated that the combination of weight loss of 10% of body mass “(read “An app to help your patient lose weight”, by Jennifer Gunter, MD).” plus 150 min/week of moderate-intensity aerobic exercise can reduce the blood glucose level.1 The ADA recommends a diet that is high in fiber, whole grains, and vegetables and that contains reduced glycemic index foods.1 A dietician can help your patients achieve this goal.
When exercise and weight loss are insufficient to lower the blood glucose level, an antihyperglycemic medication is indicated. Metformin is often recommended as the first-line drug for treating type 2 DM. The effects of treatment should be monitored with frequent blood glucose tests (fasting tests: target glucose level, <100 mg/dL; preprandial tests: target, 70 to 130 mg/dL; and post-prandial tests: target, <180 mg/dL).
Many authorities recommend that a certified diabetes nurse–educator be involved in the care of patients taking medication for diabetes. Most health insurers help patients pay for the purchase of a glucose meter and glucose test strips.
Team approach to management
Of course, once you diagnose type 2 DM, it’s important for you to work closely with your patient’s primary care provider. For a woman who has multiple chronic conditions—such as concomitant type 2 DM, hyper-tension, and dyslipidemia—the optimal scenario might be for the primary care provider to coordinate her care. For a woman of reproductive age, it might be highly advantageous to have an ObGyn involved in her reproductive care (see “Why do so many diabetic women not receive contraceptive services?”).
In a recent review of the experience with the Kaiser Permanente Northern California (KPNC) patient population, researchers reported that 62% of 122,921 healthy women but only 48% of 8,182 diabetic women had been given contraceptive counseling or a prescription for contraception.1 Similar observations have been reported in other populations.2,3
Why is it that so many diabetic women do not receive contraceptive services? One possibility is that physicians are reluctant to prescribe contraceptives that contain estrogen to diabetic patients because these women have a predisposition to vascular events; in fact, in the KPNC study, 31% of healthy women but only 13% of diabetic women were using a pill, patch, or ring, most of which contain estrogen.1
Another challenge is that primary care physicians sometimes simply run out of time during a woman’s office visit because of the myriad services they need to review and coordinate, and therefore fail to provide contraceptive counseling (think of vision exams, foot care, nutritional counseling, adjustment of medications, treatment of comorbid disorders such as dyslipidemia and hypertension, and so on). One experienced diabetologist told that me that, yes, she tells her patients “Get on a contraceptive!” but doesn’t have the time to provide detailed counseling about contraceptive options. Nor does she routinely prescribe contraceptives.
It’s likely that diabetic women are a high-risk population who need both 1) the services of a primary care provider or endocrinologist to manage their diabetes and 2) an annual visit to an ObGyn to ensure that they receive reproductive counseling and effective contraception.
Last, of particular interest to gynecologists is that, in the KPNC study, 6.5% of healthy women and 5.6% of diabetic women had been prescribed an intrauterine contraceptive.1 For diabetic women, intrauterine contraception might be an excellent option for reliable reversible contraception because it does not contain estrogen. With fewer than 6% of diabetic women using an intrauterine device, we have plenty of opportunity to provide this effective contraceptive to more of our patients.
1. Schwarz EB, Postlethwaite D, Hung YY, Lantzman E, Armstrong MA, Horberg MA. Provision of contraceptive services to women with diabetes mellitus. J Gen Int Med. 2011;27(2):196–201.
2. Schwarz EB, Maselli J, Gonzales R. Contraceptive counseling of diabetic women of reproductive age. Obstet Gynecol. 2006;107(5):1070–1074.
3. Chuang CH, Chase GA, Bensyl DM, Weisman CS. Contraceptive use by diabetic and obese women. Womens Health Issues. 2005;15(4):167–173.