Pregnancy Diabetes. Gestational Diabetes Mellitus (GDM): Prevention, Screening, and Therapy


Pregnancy Diabetes. Gestational Diabetes Mellitus (GDM): Prevention, Screening, and Therapy

Part I
Pregnancy diabetes increases the risk of later type II diabetes in women and child
In overweight women, the risk of diabetes increases regardless of pregnancy. Compared to women of normal weight, the diabetes rate was 3.6 times higher for overweight (BMI 25-30) and 15 times higher in Grade II obesity (BMI 35-40).
Every kg above normal weight increases type II diabetes risk by 16%
In particular, the risk increases to later diabetes (30 - 43 times); is shown in women with BIM >30 and gestational diabetes, when the weight gain was more than 5kg.
With a previous weight reduction of at least 2.5kg, the diabetes rate could be reduced by about 20%.
Bao W., Yeung E. et al. Long-term risk of type 2 diabetes mellitus in relation to BMI and weight change among women with a history of gestational diabetes mellitus: a prospective cohort study Diabetologia.2015 Jun;58(6):1212-9.
The obesity of pregnant women also significantly increases the frequency of high birth weight of the child (2-3 times more common macrosomia).
The diet form during pregnancy (composition or quality), as well as the excessive weight of the child already during the fetal period and after birth, show a programmatic influence on the early childhood development in the womb, and above it, a formative influence on the later development of obesity and a higher risk of diabetes type-II in the child.


Also, early childhood nutrition has an impact on the child's risk of obesity. For example, breastfeeding leads to a reduction in the risk of developing obesity in later childhood, or adulthood compared to non-breastfeeding. (DGE currently 01/2009)

Infants breastfed with breast milk later develop 20% less overweight and 25% less obesity. The benefit is better the longer breastfeeding has been. Each month of additional breastfeeding time (up to 7-9 months) the subsequent risk of obesity decreases by 4%. (  Koletzko 2011 / 2012/ 2013)

The lifestyle in childhood and adolescence has a decisive influence(the behavior of the family plays a major role).

Adequate treatment of gestational diabetes can prevent excessive birth weight (macrosomia "large for gestational age") but note that alone is not enough to prevent later obesity if the parents are also obese.
The study data are inhomogeneous for later obesity and diabetes in children. Numerous studies have shown this link, but some have not shown significant figures.
Since, in addition to lifestyle factors, genetic factors play different roles in the development of overweight and obesity in mother and child, which cannot be adequately corrected in statistical analyses, different correlations can be convincing.
The higher numbers of children born too large and too heavy are 2-3 times more often with maternal obesity and gestational diabetes; and obesity is a very relevant factor for the development of metabolic syndrome (prediabetes), from which manifest type 2 diabetes if this persists for years. Depending on the form of mother hyperglycemia during pregnancy, the later risk of diabetes in children increases between 11 and 21% compared to 4% in children of women without diabetes or gestational diabetes (Clausen 2008).
Early screening - control by gynecologists - is very important!
Early screening for the risk of gestational diabetes should be carried out as early as the 1st trimester (in the first third of pregnancy) – between the 24th until the 28th week of pregnancy. For risk groups, the screening should be carried out much earlier.
For practical reasons, the fasting blood sugar and, if there is a suspicion of risk, the HbA1c value are determined in pregnant women. 
The risk increases with the insufficiency of glucose metabolism; this can best be tested via the oral glucose load test (OGT). The fasting blood sugar level is a screening test that is not as reliable as the OGT, but since it is more complex, the general checkup during pregnancy will be done with the fasting blood sugar test and expands the determination of the HbA1c value in certain cases.
In more overweight pregnant women and also in already signs of metabolic syndrome (for which the doctor should look), an oral glucose load test is recommended; the analysis ofHbA1c ("blood sugar long-term value")is not as meaningful for early detection, it is better used for therapy control after observed sugar metabolism disorders (insulin resistance and high blood sugar level).
Clausen TD, Mathiesen ER, Hansen T, et. al. High prevalence of type 2 diabetes and pre-diabetes in adult offspring of women with gestational diabetes mellitus or type 1 diabetes: the role of intrauterine hyperglycemia.Diabetes Care.2008 Feb;31(2):340-6.
Since important functions and thus risks for the future are developed during the early imprinting (starting 1000 days of life from development in the womb), but the influences in early childhood can still change a lot, the study results should be interpreted accordingly with foresight.
The influences on the metabolism of the child and in terms of increased body weight make the process of risk formation plausible.
 In terms of weight gain or calorie requirements, all pregnant women should not eat twice as much("for two") but "twice as good".
Obese women should reduce their weight as much as possible in enough time before planning their pregnancy!
Extreme weight loss diets during pregnancy are not recommended. An overweight pregnant woman, however, should have a lower weight gain during pregnancy.
It is best to lose weight before pregnancy. For women with adiposity, a weight reduction of 5-10% of the starting weight before pregnancy can have a significant positive effect on the health and reduce some risks.  From: Diet and lifestyle during pregnancy Thieme reprint 2018 (German Journal)
To a pregnant woman with a starting position at a normal weight, a recommended pregnancy weight gain is between 11 - 16 kg. While it should be slightly more kilograms in underweight women, overweight should increase significantly less (see Table 1). The later risk of overweight in women and in children increases more with higher weight gain and especially if women were already overweight before pregnancy.
Table 1:  IOM Report 2009
BMI (kg/m2)

Weight – Gain kg
2nd and 3rd Trimester Rate
of Weight Gain kg / week
< 18.5  underweight

12,7 - 18,14kg
0,45 kg
18.5 - 24.9  normal weight

11,34 - 15,88kg
0,45 kg
25.0 - 29.9 overweight

6,8 - 11,34kg
0,27 kg
>30  obese

5 - 9,1 kg
0,23 kg
Institute of Medicine. Weight gain during pregnancy: reexamining the guidelines. Washington, D.C.: National Academy Press, 2009
Hivert  Research Journal Obesity 2016 Volume24, Issue7; Goldberg, Gail R. Nursing Standard (through 2013); Rasmussen National Academy Press, 2009; RF Goldstein, JAMA. 2017; Margerison Zilko CE, American Journal of Obstetrics and Gynecology Volume 202, Issue 6, 2010,

The normal weight gain during pregnancy is calculated based on the following factors

• At birth your baby weighs about 3.300g.

• During pregnancy, the uterus increases significantly by about 900g

• The placenta weighs around 600g

• Breasts are about 400g heavier.

• The blood volume increases by 1,200g.

• The extra fluid in the body has a weight of about 2,600g.

• About 2,500g are for more fat reserves that provide additional energy for breastfeeding.

Nutrient and energy requirements during pregnancy
The nutrient and energy requirements are increased during pregnancy, but not so much that the women must eat for two. The motto is: not twice as much, but twice as good!
The need for some micronutrients increases more than the energy requirement.
Only in the last pregnancy months the energy requirement just about 10% higher than before pregnancy.
         In the second trimester of pregnancy, the energy requirement is about 250 kcal per day higher than before
         and in the third trimester (last 3 months), the demand is 500 kcal per day higher if the physical activity remains unimpaired.
Many women, however, in the last months of pregnancy have significantly reduced physical activity, so then no increased energy intake is needed.
More details
Overweight, obesity, and type 2 diabetes - risks for mother and child
The increased intrauterine sugar supply (glucose and fructose) leads to increased fetal insulin secretion. From fetal hyperinsulinism, diabetic fetopathy can develop.
Excessive amounts of insulin have a growth-enhancing effect e.g. on white fat tissue and thus an increased birth weight (macrosomia  "large for gestational age" - birth weight above the 90th percentile; 4 kg and more).
The blood count (hemogram) can deteriorate (worse circulatory conditions and higher cardiovascular loads), and also a worse fetal surfactant formation can be the result(surfactant is important for lung development immediately after birth); thus, there may be more postnatal respiratory disorders up to respiratory distress syndrome. Overall, the risk of premature birth with further known complications increases.
For example, studies in Sweden from 1991 to 2003 show that in case of gestational diabetes, the risk of being born before the 37th week of pregnancy is 68% higher (Fadl 2010).
Fadl HE, Ostlund IKM, Magnuson AFK, et. al. Maternal and neonatal outcomes and time trends of gestational diabetes mellitus in Sweden from 1991 to 2003. Diabet Med.2010 Apr;27(4):436-41.
Early in pregnancy occurring diabetes can lead to malformations of the infant’s heart or even death if it’s undetected and thus untreated.
Under the diabetic metabolic situation of pregnant women, higher amniotic fluid production is more often observed. These and the macrosomic fetus (large or overgrown fetus) can overstretch the uterine wall so that the birth often threatens weeks too early. Furthermore, the mother is more often seen with the so-called pregnancy toxicosis (EPH gestosis Edema – Proteinuria – Hypertension; and also accompanying often liver damage. This is a high risk for the mother and the child. You can also see more urinary tract infections, which also increases the risk of premature births. 
Even if there are no complications mentioned above, numerous further complications during childbirth are increased for mother and child. Also, treatments or monitoring in intensive care units in the hospital are necessary.
Risk for mother and child in case of gestational diabetes 
·         Increased preterm birth rate, or infant death or malformations of the heart
·         Need for postnatal monitoring and therapies in intensive care 
·         Increased need for cesarean delivery
·         Risk of difficult childbirth (birth stoppage; broken collarbone, shoulder dislocation, etc.)
·         Hyperbilirubinemia (due to impaired liver function) 
·         Similarly, there is an increased risk of hypoglycemia after birth - and if hypoglycemia is detected too late, potentially permanent brain damage.
·         Increased birth weight, with increased risk of later obesity and diabetes 
·         Women with gestational diabetes have a significantly increased risk of preeclampsia (pregnancy- toxicosis).
·         Women with gestational diabetes have a 50% increased risk of developing type 2 diabetes in the long term.
German Diabetes Society e.V., the professional association of resident diabetics, the German Society for Gynaecology and Obstetrics e.V. and the Professional Association of Gynaecologists.

Prof. Dr. Werner Seebauer is Dean of Studies – Association of German Preventologists, Head of Preventive Medicine Department of Institute of Transcultural Health Sciences (European University Viadrina) and Head of Preventive Medicine – NESA (The New European Surgical Academy). Since 2000, prof. dr. Werner Seebauer worked only in preventive medicine, after ten years spent at the Frankfurt University Hospital. He is also involved in the medical professionals training for nutrition and prevention.