Recurrent gestational diabetes 181

Recurrent gestational diabetes 181

associated defect in insulin secretion. There may be a finite likely that women with GDM who were most likely to have level of pancreatic “beta cell reserve” that is further depleted

had unrecognized pregestational diabetes in their index preg- with recurring GDM. Insulin resistance is another significant

nancy include: those in whom GDM was diagnosed before 24 factor for many women who eventually develop GDM.

weeks (especially the first trimester), those who required in-

sulin before 20 weeks, and those with initial fasting plasma insulin resistance syndrome (IRS) among women with a his-

Verma and coworkers 30 examined the prevalence of the

glucose levels of ⱖ126 mg/dL (fasting glucose criterion for tory of GDM compared with controls over a period of 11

nonpregnant diabetes mellitus). Other risk factors associated years post delivery. They reported that 27.2% of women with

with an increased risk of resistant glucose intolerance after prior GDM versus only 8.2% of controls developed IRS by 11

pregnancy include obesity, high-risk ethnic group, and type years after delivery. Prepregnancy obesity was an important

2 diabetes in a first-degree relative. contributor to this increased risk. Kousta and coworkers 31 In a systematic literature review, Kim and coworkers 38

reported on normoglycemic women (34 with previous GDM found that, after a pregnancy with GDM, rates of overt dia- and 44 with no previous GDM) who were given insulin-

betes ranged from 2.6% to 70% in studies with follow up modified IV glucose tolerance tests. They found that post-

from 6 weeks to 28 years. The incidence of type 2 diabetes GDM women were more obese than controls, had evidence of

increased most in the first 5 years after the pregnancy with insulin resistance, and had higher fasting triglycerides.

GDM and seemed to plateau after 10 years. The Fourth In-

ternational Workshop-Conference on Gestational Diabetes metabolic syndrome by three different criteria (WHO 1999,

Lauenborg and colleagues 32 estimated the prevalence of the

recommended that women diagnosed with GDM undergo NCEP 2001, and the European Group for the Study of Insu-

evaluation with the 75-g OGTT test at 6 to 12 weeks after lin Resistance 2002) among Danish women with previous

delivery. 7 The American Diabetes Association in their 2004 GDM. A cohort of women were followed for a median of 9.8

position statement on gestational diabetes mellitus recom- years (6.4-17.2 years) after their pregnancy. Outcome mea-

mends that “reclassification of maternal glycemic status sures included BMI, glucose tolerance, blood pressure, lipid

should be performed at least 6 weeks after delivery and ac- profile, and insulin resistance, and they found that the prev-

cording to the guidelines of the expert committee” referenced alence of the metabolic syndrome was three times higher in

above. 1 If glucose levels are normal postpartum, reassess- the prior GDM group in comparison to the control group.

ment of glycemia should be undertaken at a minimum of Similar findings were reported by Albareda and coworkers 33 3-year intervals. All women with impaired fasting glucose

in 2005 based on their study in a Spanish population. (IFG) or impaired glucose tolerance (IGT) in the postpartum It is possible that recurrent episodes of heightened insulin

period should be tested for diabetes annually. These patients resistance, such as with recurrent GDM, place high demands

should receive intensive medical nutrition therapy and on the pancreas and contribute to an eventual decline in beta

should be placed on an individualized exercise program cell function that leads to type 2 diabetes in high-risk indi-

because of their very high risk for the development of

diabetes. 1 A summary of these recommendations together with a history of GDM. Among the 87 (13%) who completed

viduals. Peters and coworkers 34 studied 666 Latino women

with the author’s suggested evaluation plan after a preg- an additional pregnancy, the rate ratio of type 2 diabetes

nancy with GDM is provided in Figure 1 . increased significantly in comparison to women without an

Unfortunately, studies have shown that rates of postpar- additional pregnancy. Although the longevity of beta cell

tum glucose tolerance testing compliance in women diag- function may be genetically determined, some individuals

nosed with GDM have been less than optimal. Russel and may respond to repeated demands on pancreatic insulin se-

coworkers 39 retrospectively studied a cohort of 344 women cretion (as seen in normal pregnancy, obesity, and polycystic

with GDM from 2001 to 2004. They found that less than ovarian disease) in a way that eventually exhausts beta cell

one-half (45%) of women in the cohort with GDM under- reserve leading to the development of frank diabetes mellitus.

went postpartum glucose testing. More than one-third (36%) Interestingly, for the nonpregnant population, decreasing in-

of women who did have postpartum testing were found to sulin resistance through diet and exercise or medications

have persistent abnormal glucose tolerance. They found no such as metformin or rosiglitazone has been shown to reduce

independent relationship between most demographic char- the risk of subsequent type 2 diabetes or delay its onset. 35-37

acteristics and postpartum testing. Postpartum testing was strongly associated only with the attendance at the postpar- tum visit as shown by the 54% postpartum testing rate com-

Postpartum and

pared with 17% of women who did not attend their postpar-

Long-Term Management

tum visit. Therefore, postpartum visits are a critical link to

after Gestational Diabetes compliance with follow-up testing.

These data highlight the importance of postpartum and The definition of GDM encompasses a fairly wide spectrum

preconception care to allow further assessment of modifiable of disease. The degree of glucose intolerance and the time of

risk factors for women with previous GDM, whether or not onset varies, ranging from transient mild hyperglycemia lim-

they are considering another pregnancy. If not feasible for ited to pregnancy to unrecognized pregestational diabetes to

those with subsequent pregnancies, then early prenatal care pregestational metabolic syndrome (insulin resistance) with

to allow timely GDM screening and management is appro- or without features of PCOS. Although data are lacking, it is

priate.

182 J.N. Bottalico

Figure 1 Suggested evaluation plan for women with a previous history of gestational diabetes.