What is gestational diabetes? (GD) ?
According to the World Health Organization (WHO), gestational diabetes is a medical complication of pregnancy, defined as a disorder of carbohydrate tolerance leading to hyperglycemia of variable severity, beginning or first diagnosed during pregnancy, irrespective of the treatment required and the evolution in the post-partum period.
The risks associated with GD are correlated with the severity of hyperglycemia, and appropriate management can reduce fetomaternal complications.
How common is G.D.?
Gestational diabetes is the most frequent complication of pregnancy,
Its prevalence varies widely throughout the world, ranging from 6 to 17%.
If multiparity = 19%.
In Algeria, two epidemiological surveys have been carried out on GDM, using the same methodology and WHO criteria (see table).
Using the new IADPSG criteria, the frequency of GD is doubled. Given that gestational diabetes is a risk factor for type 2 diabetes, we understand the importance of screening, management and follow-up in the immediate and distant post-partum period.
What are the risk factors for G.D.?[1]
– 1st-degree family history of type 2 diabetes
– Macrosomia in siblings
– Family obesity
– Premature vascular disease (hypertension, coronary artery disease, stroke),
– Personal non-obstetrical history
– History of macrosomia (birth weight ≥ 4000 g),
– Patient’s constitutional obesity [Obesity or overweight prior to pregnancy are identified as risk factors for gestational diabetes, threshold body mass index (BMI) value is ≥ 25 kg/m²]
– Age ≥ 35 years,
– HYPERTENSION
– Gestational diabetes
– Obstetrical history
– Spontaneous abortion
– Unexplained in utero death
– Macrosomia or intrauterine growth retardation
– Congenital malformations
– Previous gestational obesity (> 15Kg)
– Hydramnios -HTA gravidarum.
– Polycystic ovary syndrome.
– On current pregnancy
– Macrosomia
– Recurrent urinary tract infections
– Hydramnios
– Excessive weight gain
– Glycosuria
What are the short-term maternal consequences of GD ?
– Urinary tract infections (12.4%)
– Pregnancy-induced hypertension (21.2% vs. 7.1% p<0.002)[2]
– Increased caesarean section rate (30.3% vs. 10.3% p<0.003)
What are the short-term fetal and neonatal consequences of GD?
– Perinatal mortality: no significant difference when glycemic control is good.
– Fetal macrosomia: can be defined as a weight greater than a threshold value of 4,000 g.
Metabolic complications[3]
– Hypoglycemia: blood glucose < 0.30 g/l at term and < 0.20 g/l in premature infants ((66.7% vs. 1 ; 6%) p<0.001)
– Hypocalcemia: calcemia < 80 mg/l at term
Other complications
– Shoulder dystocia
– Respiratory and cardiac complications
Transfer to intensive care unit
How to detect ?
- In 2010, an international consensus was proposed by the IADPSG[1] (International Association of diabetes and Pregnancy Study Group) on screening and diagnostic procedures for GDM.
- First trimester: Experts recommend fasting blood glucose or glycated hemoglobin (HbA1c at 6.5% threshold) in early pregnancy, to screen patients with previous or unrecognized type 2 diabetes.
- Between the 24th and 28th week of amenorrhea: For all pregnant women whose FPG was < 0.92 g/l, or who were not screened in the 1st trimester, a 75 g glucose OGTT (WHO test) is recommended.
What are the diagnostic criteria for GD?
A single pathological value is sufficient for the diagnosis of gestational diabetes. (See table)
Which pregnant women should be screened?
The CNGOF and the SFD (2010)[1] suggest targeted screening: In the presence of one or more of the following risk factors:
What are the glycemic targets?
In the present state of knowledge, the currently validated objective is to achieve fasting blood glucose levels below 0.95 g/L (grade A). To date, there are no interventional studies validating the 0.92 g/L threshold as a therapeutic objective. There are no data to suggest that postprandial measurement at one or two hours should be preferred, or which thresholds should be used: 1.30 g/L or 1.40 g/L at one hour, or 1.20 g/L at two hours. The latter threshold is currently recommended (grade A).
What are the treatment options ?
– Dietary measures [1]:
– 1st treatment for GDM.
– Achieve glycemic targets in 20-70% of cases.
– Must be individualized: 1800 to 2000 kcal/d (50% carbohydrates)
– Physical activity[2]:
– Walking, swimming
What are the requirements for optimal diabetes self-monitoring?
- It will be based on the same therapeutic principles, from pregnancy planning to delivery. This involves optimized insulin therapy and intensified self-monitoring of blood glucose, combined with a suitable diet.
- Self-monitoring of blood glucose (SMBG) enables patients to be monitored and insulin therapy to be indicated (Grade C). When women are treated with insulin, SMBG is essential to adapt insulin doses. SMBG is recommended between 4 and 6 times a day[3] (at least once on an empty stomach and two hours after meals, depending on the treatment – diet or insulin – and the balance achieved (professional agreement). SMBG should be continued into the immediate post-partum period. Devices must be calibrated in accordance with current procedures.
- Insulin therapy is indicated when diet is insufficient to achieve (or maintain) glycemic targets.
- Immediate post-partum
- Glycemic monitoring for a few days to verify return to normal.
- Appropriate contraception.
- Reclassification of diabetes 6 to 12 weeks after delivery.
- Long-term monitoring: Oral glucose tolerance tests (OGTT) every 12 to 24 months.
What is the medium-term outcome of mothers who have experienced a GD??
- Recurrence of diabetes in subsequent pregnancies: 25 to 36%/WHO criteria (29.7% in the thesis series by Pr M. BACHAOUI EHU Oran)
- 15 to 60% become diabetic within 20 years (26.8% within 12 years – thesis series by Pr M. BACHAOUI EHU Oran)
What is the long-term outcome for children?
- Obesity (after the first few years of life)
- Diabetes (earlier and more frequent)
————————————————————————————————————————————————–
[2] Tobias & al, Physical activity before and during pregnancy and risk of gestational diabetes mellitus a meta-analysis. Diabetes care 2011; 34:223-9.
[3] Référentiel élaboré par le Collège national des gynécologues et obstétriciens français (CNGOF) et par la Société francophone du diabète (SFD), Extrait de Médecine des maladies Métaboliques – Décembre 2010 – Vol. 4 – N°6
[1] Mimouni-Zerguini S. Diabète Gestationnel : facteurs de risque, évolution et conséquences périnatales. Médecine des maladies Métaboliques – Décembre 2009 – Vol. 3
[2] P48 – S. Bensalem & al Morbidité fœto-maternelle chez les femmes présentant un diabète gestationnel dans la Wilaya de Constantine
[3] P48 – S. Bensalem & al Morbidité fœto-maternelle chez les femmes présentant un diabète gestationnel dans la Wilaya de Constantine
[4] International Association of Diabetes and Pregnancy Study Groups Consensus Panel, International Association of Diabetes and Pregnancy Study Groups Recommendations on the Diagnosis and Classification of Hyperglycemia in Pregnancy , Diabetes Care 33, no. 3 (mars 1, 2010) : 676 -682.
[5] Référentiel élaboré par le Collège national des gynécologues et obstétriciens français (CNGOF) et par la Société francophone du diabète (SFD), Extrait de Médecine des maladies Métaboliques – Décembre 2010 – Vol. 4 – N°6
[6] Zhang & al, Dietary fiber in intake, Dietary glycemic load and risk for gestational diabetes mellitus. Diabetes care; 29:2223-30.
[7] Tobias & al, Physical activity before and during pregnancy and risk of gestational diabetes mellitus a meta-analysis. Diabetes care 2011; 34:223-9.
[8] Référentiel élaboré par le Collège national des gynécologues et obstétriciens français (CNGOF) et par la Société francophone du diabète (SFD), Extrait de Médecine des maladies Métaboliques – Décembre 2010 – Vol. 4 – N°6
