Gestational Diabetes

Presented by: Dr. Neville M.G & Dr. Jonas L.F ( O&G Housemen SGH)Supervisor: Dr Muniswaran Ganeshan (MRCOG, M MED O&G)

Gestational diabetes is carbohydrate intolerance of variable severity, with onset or first recognition of hyperglycaemia during pregnancy.

Gestational diabetes is a condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy (especially during third trimester). 

Definitions

Introduction• Represents most common metabolic complication during pregnancy; early manifestation of type 2 diabetes

• Studies have shown that gestational hyperglycaemia is associated with higher incidence of adverse maternal and fetal outcomes than is seen in normal pregnancy

• High proportion (>50%) have GDM in the subsequent pregnancy

• Increased risk of subsequent T2DM - approx. 50 % of women with GDM progressed to DM within 5 years duration - 35 to 60% of women develop T2DM within 10 years after being diagnosed with GDM.

PATHOPHYSIOLOGY

Early in pregnancy, maternal estrogen and progesterone increase and promote pancreatic ß-cell hyperplasia and increased insulin release

As pregnancy progresses, increased levels of human placental lactogen, cortisol, prolactin, progesterone, and estrogen lead to insulin resistance in peripheral tissues.

Table 1 describes the diabetogenic potency and time of peak effect of these hormones. The timing of these hormonal events is important in regard to scheduling testing for GDM

Hormone  Peak elevation (weeks) Diabetogenic potency

ProlactinEstradiolHPLCortisolProgesterone

1026262632

Weak Very weakModerateVery strongStrong

Adapted from Jovanovic-Peterson L, Peterson C: Review of gestational diabetes mellitus and low-calorie diet and physical exercise as therapy. Diabetes Metab Rev 12:287-308, 1996.

GDM results when there is delayed or insufficient insulin secretion in the presence of increasing peripheral resistance

Risk factors (WHO/NICE)

Patients were considered to be risk-factor positive if any of the following is present:

age 35 years and above previous macrosomic baby with birth weight 4.0kg

or more previous unexplained still birth previous baby with congenital abnormally previous pregnancy with gestational diabetes

mellitus history of Diabetes Mellitus in first degree relatives Obese or pre-pregnancy weight more than 80kg,

BMI > 30Ethnicity

In the public health service in Malaysia, screening for gestational diabetes is done selectively where only patients with risk factors are screened and diagnosed using a 1-step 75g OGTT.

This is done at least once at or around 24-28 weeks gestation, unless there are indications for it to be done earlier.

However, as Asian ethnicity is considered a risk factor, selectively screening our women without regard to their Asian background may results in gross under-detection of gestational diabetes (~50%)

On the other hand, to have all pregnant women undergo the 75g OGTT may be cumbersome and have some economic implications, particularly in low resource areas.

Effects on Pregnant Women Pre-eclampsia

Polyhydramnios

Operative delivery in pregnancies complicated with GDM/length of hospital stay, risks of infection.

significant risk of developing diabetes later in life

higher triglycerides,free fatty acids,and lower high-density level (HDL) cholesterol. (cardiovascular risk)

Effects on Fetus• increased rate of stillbirths in untreated GDM

• increased risk of macrosomia (fetal weight >90th percentile for gestational age or >4 kg)

• fetal hyperinsulinemia and subsequently increase fetal growth

• shoulder dystocia is increased 2-6X; brachial plexus injury

• Neonatal hypoglycemia. In severe case, intravenous (IV) glucose solution may needed or else the baby will suffer brain damage

Respiratory distress symptomNeonatal jaundice/hyperbilirubinemia

Long Term Outcome:IGT in adolescent childrenBy 8 years of age, 50% of children of diabetic

mothers had weights above the 90th percentile compared to children of women without diabetes

high incidence of obesityneurodevelopmental course- child’s poorer

performance on standard measures of psychomotor development at 6 and 9 years of age.

How to Diagnose GDMFBS??RBS??Glucosuria??MOGTT??

ANSWER:MOGTTSo how’s it done??Screening for GDM is performed with a 75-

g oral glucose load given between 24 and 28 weeks gestation, with venous plasma glucose level taken pre and 2 hours post. The screening test is performed at a time when the diabetogenic effects of pregnancy are peaking.

DiagnosisWHO HAPO ADA IADPSG

Fasting 7.0 5.1 5.3 5.1

2 hours 7.8 8.5 8.6 8.5

notes One abnormalvalue required

Two abnormalvalue required

One abnormalvalue required

HAPO STUDY: This was an international multicentre observation

study in which over 23,000 pregnant women were assessed for glucose intolerance using the 75 g OGTT. The results remained blinded, providing fasting glucose <5.8 mmol/l and 2-h glucose <11.1 mmol/l.

The study showed relation between high blood glucose levels with macrosomia n neonatal hypoglycemia

Other outcomes: caesarean section, shoulder dystocia,

birth injury, pre-eclampsia, premature delivery, admission to neonatal intensive care and neonatal hyperbilirubinaemia

ACHOISWomen with gestational diabetes (WHO criteria) were

randomized either to an intervention group which received dietary advice, glucose monitoring and insulin therapy if required, or a control group receiving usual care.

The intervention group showed a significantly lower rate (1% vs 4%) of serious perinatal complications including death, shoulder dystocia, bone fracture and nerve palsy.

rates of caesarean section were similar between the intervention and the control group

however there was an increased incidence of induction of labour in the intervention group (39% vs 29%).

MANAGEMENT:Exercise

. Jovanovic-Peterson and associates studied 19 women with GDM, assigning 9 to dietary treatment and 10 to diet plus 20 minutes of monitored exercise 3 times a week for 6 weeks.

They found a significantly lower OGTT and fasting blood glucose in patients assigned to the exercise group beginning 6 weeks after initiating therapy.

What type of exercise??Non weight bearing (ex: swimming, cycling,

brisk walking)

Diet control ADA has recommended dietary therapy to

start with 2,000–2,500 kcal/day (35 kcal/kg present pregnancy weight), with 50–60% carbohydrates (complex, high fiber), 10–20% protein, and 25–30% fat (<10% saturated). New ADA recommendations specify a protein level of 10–20% of calories but now allow greater flexibility in the levels of carbohydrate and fat.

InsulinThe ACOG criteria for initiating insulin

therapy include a fasting plasma glucose level 5.8 mmol/l and 2-hour plasma postprandial levels 6.6 mmol/l.

Total insulin doses can be calculated and given with split dosing by three injections. If insulin is required, the target plasma glucose levels are:

fasting 1hour 2 hours 2-6 am

3.3-5.8 mmol/l

Not > 7.2-7.8 mmol/l

< 6.7 mmol/l 3.3- 5.0 mmol/l

OHA1) Gilbenclamide (sulphonylurea): MOA: enhance insulin

secretion by beta cells. Older sulphonylurea medications such as tolbutamide and chlorpropamide can cause fetal hyperinsulinaemia. Glibenclamide has minimal passage across the placenta.

Study: A trial published in 2000 randomized 404 women with gestational diabetes to receive either glibenclamide or insulin treatment.

Results: no difference in the glycaemic control achieved between the two groups and no significant differences in rates of macrosomia or metabolic neonatal complication.

2) Metformin: MOA: increase insulin sensitivity. Study: MiG trial randomized 751 women to insulin or

metformin treatment with insulin supplementation if required. Results:There was no difference in peri-natal morbidity

between the two groups. 46% of the metformin group received supplemental insulin to meet glucose targets.

Timing and mode of deliveryTiming:-Uncomplicated, well controlled DM not requiring insulin with

normal fetal growth- 38 to 40 weeks-GDM requiring insulin therapy- 38 weeks/earlier if indicated

Mode Of Delivery:Studies have documented an increase in the rate of shoulder

dystocia when macrosomia is suspected. Consequently, estimated fetal weight plays an important role in the decision-making process for route of delivery. When it is suspected that the fetus is macrosomic, cesarean delivery should be considered. Providers must remember that ultrasonography has a range of error of ±10–15% in estimating fetal weight at term.

PearlsLook for unrecognized DM2 or GDM at

1st prenatal visit if risk factors New criteria for diagnosing GDM ’ 2-hr, 75 g

OGTT Increased no. of women with GDM Rx hyperglycemia in pregnancy to

prevent maternal & fetal complications Lifestyle modifications: diet & exercise (during &

after pregnancy) Pharmacologic options: MFM, Glyburide, Insulin Screen for DM2 or pre-diabetes at 6-12 wks post-

partum

The end