Diabetes and Pregnancy
Gestational diabetes (which develops or is diagnosed for the first time during pregnancy) encompasses two distinct conditions:
Diabetes that actually develops during pregnancy, usually in the second trimester, and resolves postpartum, with a significant proportion of cases recurring as type 2 diabetes later in life.
Diabetes that existed prior to pregnancy (mostly type 2) but was previously undiagnosed, which is discovered during pregnancy and therefore persists after childbirth.
Pre-pregnancy diabetes, which can be type 1 or type 2, and gestational diabetes are associated with a range of complications or conditions in both the mother and the child, both in the short and long term. (Galtier F, 2010)
Fetal and Maternal Complications of Gestational Diabetes
In the mother, gestational diabetes is associated with an increased risk of pregnancy-induced hypertension, preeclampsia, and cesarean section (CNGOF and SFD, 2010). It typically appears in the second half of pregnancy (a period of "physiological" insulin resistance) and therefore does not pose a risk of fetal malformations, as blood glucose levels are normal during organogenesis. The main complication for the child is macrosomia (high birth weight), which is associated with an increased risk of shoulder dystocia at birth (failure of the shoulders to engage after the head has been delivered). In the longer term, children may have an increased risk of being overweight or obese and of developing type 2 diabetes. (Fraser A, 2014)
Women who have had gestational diabetes also have an increased long-term risk of subsequently developing type 2 diabetes (in 15 to 60% of cases, depending on the study groups and the duration of follow-up). The French Diagest 2 study showed that 6 years after childbirth, 18% of women with gestational diabetes had developed diabetes, and 35% by 11 years (Fontaine P et al, 2014). The risk increases over time and persists for at least 25 years. The risk of developing metabolic syndrome is 2 to 5 times higher, and the risk of cardiovascular disease is approximately 1.7 times higher. (CNGOF and SFD, 2010)
Fetal and Maternal Complications of Pre-gestational Diabetes
Pregnancy in a woman with type 1 or type 2 diabetes carries potential risks for both the mother and the child. Optimized care, both before conception and throughout the entire pregnancy, helps reduce these risks, which nevertheless remain higher than in the general population (SFD Guidelines, 2010). Close coordination between the gynecology-obstetrics team, the endocrinology team, and the primary care physician is recommended, as well as the implementation of an optimized insulin regimen as early as possible, in order to achieve and maintain strict glycemic targets that will ensure a favorable pregnancy outcome for both the mother and the child. (HAS, 2013)
Prevalence of gestational and pre-gestational diabetes in France
Until recently, very little French data on the prevalence of gestational and pre-gestational diabetes was available. In 2005, the Audipog registry, populated by voluntary public and private maternity hospitals from all regions of France, reported a prevalence of gestational diabetes of 4.5%. In 2010, in the National Perinatal Survey (ENP), which is representative of births in France, gestational diabetes affected 7.2% of women, insulin-dependent pre-gestational diabetes 0.3%, and non-insulin-dependent diabetes 0.2% (Blondel B et al, 2011). In 2011, according to analyses by the CNAMTS based on data from medical-administrative databases (SNIIRAM and PMSI), 6.4% of women reportedly had gestational diabetes during their pregnancy, 0.2% had type 1 pre-gestational diabetes, and 0.2% had type 2 pre-gestational diabetes. (Billionnet C et al, 2014). In 2016, according to the National Perinatal Survey (ENP), gestational diabetes affected 10.8% of women, of whom 0.3% had insulin-dependent pre-gestational diabetes and 0.2% had non-insulin-dependent pre-gestational diabetes. (Blondel B et al., 2016; Blondel et al., 2017)
Probable geographic and ethnic disparities in the prevalence of gestational diabetes
Although geographic disparities have yet to be described in greater detail, partial data suggest significant variability between regions, similar to the disparities observed for type 2 diabetes and obesity. In Réunion, the prevalence in hospital settings in 2013 was 14.4% (ORS Réunion, 2015). Other data from Seine-Saint-Denis indicated a prevalence of gestational diabetes of 16.5% in 2013, with significant variations depending on the women’s ethnic origin. (Cosson E et al, 2014)
Expected trends in the prevalence of gestational diabetes
The increasingly frequent presence of certain risk factors in the population, particularly maternal age at pregnancy (≥ 35 years) and maternal overweight or obesity prior to pregnancy, raises concerns about an increase in the prevalence of gestational diabetes. A growing proportion of women begin their pregnancies after age 35 and/or while overweight. The National Perinatal Surveys, conducted in France on a representative sample of women at the time of delivery, show that between 2003 and 2010, the proportion of mothers who began their pregnancy after age 35 rose from 15.9% to 19.2%, and those who began their pregnancy overweight rose from 15.4% to 17.3%, while the proportion of those who were obese rose from 7.4% to 9.9%. (Blondel B et al, 2011)
At the same time, new screening guidelines were published in 2010. (CNGOF and SFD, 2010). These recommendations propose screening based on risk factors (maternal age ≥35 years, BMI ≥25 kg/m², history of diabetes in first-degree relatives, personal history of GD or macrosomic infant).
Establishment of a surveillance system for gestational and pre-gestational diabetes
In 2015, the InVS established a surveillance system for gestational and pre-gestational diabetes. This project is jointly led by the diabetes surveillance program and the perinatal surveillance program. The main objectives of this surveillance system are to:
describe the prevalence of gestational and pre-gestational diabetes and their trends over time in the general population,
describe screening practices for gestational diabetes during pregnancy and type 2 diabetes after childbirth,
describe geographical, socioeconomic, and country-of-origin variations in the prevalence and screening practices for gestational diabetes,
estimate the frequency of fetal, neonatal, and maternal complications associated with gestational and pre-gestational diabetes.
Preliminary results
An analysis of data from the Epifane study (Salanave B, et al, 2014) showed that in mainland France in 2012, the prevalence of GDM was 8.0%, of which 26.9% were treated with insulin. In total, 75.9% of women reported having been screened via an oral glucose tolerance test, whereas the proportion of women presenting at least one of the following three risk factors—age ≥ 35 years, overweight/obesity, or a history of gestational diabetes—and included in the screening guidelines was only 42.0%. Despite the high proportion of women screened, 18.8% of women aged 35 or older, 15.6% of overweight women, 10.3% of obese women, and 5.3% of women with a history of GD reported not having been screened. (Regnault N, 2016)
Gestational diabetes: a unique opportunity to identify women at risk for type 2 diabetes to prevent its onset
Gestational diabetes can be considered a warning sign of type 2 diabetes and, more generally, of metabolic abnormalities. It helps identify women (and potentially their children) who could benefit most from prevention programs targeting modifiable factors, particularly physical activity and diet. Indeed, it has been shown that interventions aimed at modifying lifestyle habits are an effective means of preventing T2D in individuals at high risk for T2D. (Tuomilehto J, 2001; Knowler WC, 2002) Women with a history of gestational diabetes can therefore particularly benefit from this type of intervention. In a study called the "Tianjin Gestational Diabetes Mellitus Prevention Program," such an intervention resulted, after one year of follow-up, in beneficial changes in weight, body mass index (BMI), body fat, waist circumference, plasma insulin levels, physical activity, and diet. (Hu G, 2012) Other studies have shown similar results. (Ferrara A, 2011; Reinhardt JA, 2012) Furthermore, in the Diabetes Prevention Program (DPP), an intensive intervention aimed at modifying the lifestyle habits of women with a history of gestational diabetes reduced the incidence of diabetes by 50% compared to the control group after 3 years. (Ratner RE, 2008)
References
Blondel et al. National Perinatal Survey: Births and Healthcare Facilities: Current Status and Trends Since 2010. 2016 Report
Blondel et al. Trends in perinatal health in metropolitan France from 1995 to 2016: Results from the French National Perinatal Surveys. J Gynecol Obstet Human Reprod. 2017,46:701-713.
Regnault N et al. Gestational diabetes in France in 2012: screening, prevalence, and management during pregnancy. Bull Epidémiol Hebd. 2016;(9):164-73.
French Association of Women with Diabetes
Billionnet C et al. Gestational diabetes and pregnancy: data from the French population, 2011. Diabetes & Metabolism. 2014. (40) Suppl1. PA15.
Blondel B et al. Births in 2010 and their evolution since 2003. Report. 2011
National College of French Gynecologists and Obstetricians and Francophone Diabetes Society. Gestational diabetes: Text of the recommendations. J Gynecol Obstet Biol Reprod 2010, 39:S1-S342
Cosson E et al. The diagnostic and prognostic performance of a selective screening strategy for gestational diabetes mellitus according to ethnicity in Europe. J Clin Endocrinol Metab. 2014 Mar,99(3):996-1005. doi: 10.1210/jc.2013-3383.
Ferrara A, et al. A pregnancy and postpartum lifestyle intervention in women with gestational diabetes mellitus reduces diabetes risk factors: A feasibility randomized controlled trial. Diabetes Care 2011, 34:1519–1525.
Fraser A et al. Long-term health outcomes in offspring born to women with diabetes in pregnancy. Curr Diab Rep. 2014,14(5):489. doi: 10.1007/s11892-014-0489-x.
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Hu G, et al. Tianjin Gestational Diabetes Mellitus Prevention Program: Study design, methods, and 1-year interim report on the feasibility of lifestyle intervention program. Diabetes Res Clin Pract 2012,98:508–517
Reinhardt JA, et al. Implementing lifestyle change through phone-based motivational interviewing in rural women with a history of gestational diabetes mellitus. Health Promot J Austr 2012,23:5–9
Knowler WC, et al. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin. N Engl J Med 2002,346:393–403
Ratner RE, Christophi CA, Metzger BE, et al. Prevention of diabetes in women with a history of gestational diabetes: Effects of metformin and lifestyle interventions. J Clin Endocrinol Metab 2008,93:4774–4779
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Francophone Diabetes Society. Management of pregnancy in type 1 diabetes. Guidelines. Méd Mal Métabol 2010,4(6):1-14.
Tuomilehto J., et al. Prevention of type 2 diabetes mellitus by lifestyle changes among subjects with impaired glucose tolerance. N Engl J Med 2001,344:1343–1350
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