178 J.N. Bottalico

178 J.N. Bottalico

dL). GDM recurrence was found in 69% (54) of women. Excessive weight is an important public health concern in Recurrence of GDM was more common with an index preg-

the United States, as well as other affluent societies. Pleis and nancy parity ⱖ1, BMI ⱖ30 kg/m 2 coworkers , a GDM diagnosis at ⱕ24 11 reported that, by the end of 2000, 34% of adult gestational weeks in the first pregnancy, and insulin require-

Americans were overweight and another 27% were obese. ment in the first pregnancy. A weight gain of ⱖ15 lbs and an

This represented an increase of 75% compared with 1980 interval between pregnancies of ⱕ24 months had the stron-

statistics. These data showed that, at the end of 2000, more gest association with recurrence of GDM.

than 50% of the adults in the United States were either over-

weight or obese. United States data from 1997 and 1998 for tudinal study in 2001 of a predominantly white cohort of 651

MacNeill and coworkers 6 published a retrospective longi-

women aged 18 to 24 and 25 to 44 revealed an estimated women in Nova Scotia diagnosed with GDM during a preg-

prevalence of overweight (BMI ⱖ 25 kg/m 2 ) or obese (BMI ⱖ nancy that occurred between 1980 and 1996 and who had at

30 kg/m 2 ) of over 30% for the 18 to 24 age group and over least one subsequent pregnancy during that time period. The

40% for the 25 to 44 group. 12 An increased prevalence of screening method employed was a 50-g 1-hour glucose load.

obesity in U.S. adolescents has also been documented and

A value of ⱖ140 mg/dL was considered a positive screen and associated with declining levels of physical activity. 13 The was followed by a 3-hour oral glucose tolerance test with

links between obesity, insulin resistance, and type 2 diabetes 100 g of glucose that required more than one glucose over the

mellitus are well known, and the long-term complications of threshold values for a positive test (fasting ⱖ95mg/dL, 1

obesity are numerous. The strong association between in- hour ⱖ190 mg/dL, 2 hours ⱖ165 mg/dL, and 3 hours 145

creased BMI and higher risks for GDM has been clearly es- mg/dL). These criteria combine elements from the current

tablished.

There is also growing recognition of the importance of the the 100-g glucose 3-hour OGTT (fasting ⱖ95mg/dL, 1-hour

ADA endorsed Carpenter and Coustan 7 threshold values for

metabolic syndrome as a multiplex risk factor for cardiovas- ⱖ 180 mg/dL, 2-hour ⱖ155 mg/dL, and 3-hour 140 mg/dL)

cular disease and type 2 diabetes. In women, the metabolic

syndrome is defined by the presence of three or more of the ⱖ 105mg/dL, 1 hour ⱖ190 mg/dL, 2 hours ⱖ165 mg/dL,

and the National Diabetes Data Group 8 values (fasting

following criteria: abdominal obesity (waist circumference and 3 hours 145 mg/dL), which also require more than one

⬎88 cm or 34.7 inches), elevated triglycerides (ⱖ150 mg/ abnormal value for a positive test. The rate of recurrence of

dL), high-density lipoprotein (⬍50 mg/dL), high blood pres- GDM in the subsequent pregnancy was found to be 35.6%.

sure (ⱖ130/85 mm Hg), and elevated fasting glucose (110 Multivariate regression models showed that infant birth

mg/dL). 14 It should be noted that the current definition of weight in the index pregnancy and maternal prepregnancy

impaired fasting glucose is 100 to 125 mg/dL. 1 The estimated weight before the subsequent pregnancy were predictive of

prevalence of the metabolic syndrome in women is 24%, recurrent GDM.

with prevalence increasing with age as reported by Ford and

coworkers using data from the National Health and Nutrition diabetes service in New South Wales, Australia reported a

A 1998 study by Foster-Powell and Cheung 9 through a

Survey (NHANES III). 15 For 4549 female subjects reported retrospective review of 540 women with GDM managed be-

by Ford, metabolic syndrome prevalence was about 6% in tween 1990 and 1996. There was a GDM recurrence rate of

those 20 to 29 years of age, 14% in those 30 to 39 years of age, 70% using a 2-hour 75-g OGTT for diagnosis with modified

20% in those 40 to 49 years of age, and ⬎30% for women WHO threshold values. Finally, Danilenko-Dixon and col-

older than 50 years of age. As with obesity, the pathophysi- leagues 10 in 2000 reported that perinatal outcomes in women

ologic features of the metabolic syndrome are likely to be with previous gestational diabetes but with normal glucose

associated with a variety of pregnancy complications, includ- tolerance tests during a subsequent pregnancy were not im-

ing GDM.

proved with regard to birth weight, macrosomia, route of delivery, and neonatal complications.

Unfortunately, these studies on the recurrence of GDM

United States

suffer from the limitations of having no formal proof that

Diabetes Prevalence:

some of the women did not have undiagnosed type 2 diabe-

Diagnosed and Undiagnosed

tes, impaired fasting glucose, or impaired glucose tolerance using current ADA criteria before the subsequent pregnancy.

National estimates on diabetes prevalence have been pub- lished by the Centers for Disease Control and Prevention

(CDC) in Atlanta. 16 The total prevalence of frank diabetes

Increasing Prevalence

mellitus among women age 20 years or older in the United

of Pre-Diabetic Risk

States in 2005 was 9.7 million, or 8.8% of all women in this

Factors in the United States age group. The prevalence of diabetes by race and ethnicity

among people 20 years of age or older in the United States in Since GDM may very well be a “tip of the iceberg” phenom-

2005 was an estimated 8.7% prevalence for all non-Hispanic enon for many women, it is important to consider the epide-

whites, 13.3% for non-Hispanic blacks, and about 9.5% of miologic landscape affecting the first occurrence of GDM as

Hispanic/Latino Americans. The rates are also higher for well as the risks for recurrent GDM in subsequent pregnan-

American-Indians, Alaskan natives, Asian Americans, and cies and the longer term risk of type 2 diabetes.

Pacific Islanders. Many of these women will have DM iden-