Gestational diabetes

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Description

Gestational diabetes mellitus is characterised by hyperglycaemia first recognised in pregnancy. Its prevalence varies widely in the literature, but is thought to effect 4-7.5% of all pregnancies  and is increasing  more common among older women, obese women and certain ethnic groups. It usually presents after the beginning of the second trimester.

Pathological Process

In pregnancy, some women develop insulin resistance, which may stem from increased maternal adiposity and several hormones produced during pregnancy block the action of insulin at a cellular level, i.e. Tumor Necrosis Factor Alpha, human placental lactogen and placental growth hormone. As a result, blood glucose levels rise and more insulin is produced in response. As the pregnancy progress, the insulin demands increase, and thus, insulin resistance also increases due to rising levels of pregnancy hormones. However, this is a normal physiological change in pregnancy. Beta cells in the pancreas increase insulin production to compensate for this, and so in a normal pregnancy blood glucose level changes are small compared to the large changes in insulin resistance. Women who present with gestational diabetes mellitus have less of a degree of compensation at the Beta cell than women who do not present with gestational diabetes . Less than 10% of women who present with gestational diabetes have been shown to have antibodies to pancreatic islets of Beta cells in their circulation. It has been postulated that their gestational diabetes may stem from autoimmune damage to Beta cells . Some gestational diabetes mellitus cases have been shown to be due to genetic defects in Beta cells . Others may be chronic hyperglycaemia first detected at pregnancy, which may explain why most women who develop gestational diabetes mellitus go on to develop type II diabetes mellitus. The exact mechanism for increased insulin resistance is still largely unclear. Maternal obesity may contribute as up-regulation of cytokines and adipokines impacts insulin pathways and skeletal muscle insulin signalling is impaired .

Consequences of Gestational Diabetes Mellitus

For Mother

Gestational diabetes mellitus is related to higher rates of:

<span style="line-height: 1.5em;" />Pre-eclampsia

Caesarean section

Gestational diabetes mellitus in subsequent pregnancies

Gestational diabetes mellitus typically resolves after birth. However, there have been many studies detailing the significantly increased risk of developing type II diabetes mellitus after having gestational diabetes mellitus, particularly in the first 5 years postpartum .

For Baby

• Macrosomnia: leading to higher rates of injury to mother and baby , and higher rates of childhood overweight and obesity 
• Fetal hyperglycaemia and hyperinsulinimia
• Preterm delivery
• Intensive neonatal care
• High neonatal body fat percentage
• Clinical neonatal hypoglycaemia 

Diagnositc Procedures

Risk Factors

Several factors have been identified which increase the risk of women developing gestational diabetes mellitus. These include:

• Older age
• Ethnicity, namely black, Native American, Pacific Islander, Hispanic, South or East Asian and Indigenous Australian
• High pre-pregnancy BMI
• Family history of diabetes
• Previous episode of gestational diabetes mellitus
• Multigravid women
• Excessive weight gain during pregnancy
• Short stature
• Smoking

Local regimens use various screening tools in conjunction with these risk factors to identify women in need of further testing.

Screening for Gestational Diabetes Mellitus

Gestational diabetes mellitus can only be confirmed by an abnormal glucose tolerance test.

The World Health Organization classify gestational diabetes mellitus if one or more of the following criterias are met

• • Fasting plasma glucose 5.1–6.9 mmol/L (92–125 mg/dL)
  • 1-hour plasma glucose 10.0 mmol/L (180 mg/dL) following a 75 g oral glucose load 2-hour plasma glucose 8.5–11.0 mmol/L (153–199 mg/dL) following a 75 g oral glucose load

Medical Management / Interventions

Diet

Dietary interventions have long been a cornerstone of treatment for GDM. Women diagnosed with GDM are routinely referred to a dietician. The challenge of GDM management for dieticians is striking the delicate balance between keeping maternal insulin low without restricting fetal growth. A Cochrane review in 2008 examined 3 trials investigating the effects of diet on preventing GDM, found inconclusive results .

Medication

When dietary management fails, insulin is considered the safest treatment, as free insulin cannot cross the placenta.  Although insulin is time tested first line therapy, its use involves practical challenges. Recent evidence is supportive of use of OHA (oral hypoglycaemic agents ), especially metformin and glibenclamide. Metformin, when compared with insulin, is associated with less weight gain, better satisfaction and acceptance and with a lower risk of maternal hypoglycaemia.

The Role for Physiotherapy

Exercise has many health related benefits and it is proven method for effective prevention and treatment of T2DM. There are some contraindications that should be considered while prescribing exercise to the pregnant women.

Absolute contraindications

Relative contraindications

• Haemodynamically significant heart disease • Restrictive lung disease • Incompetent cervix/cerclage • Multiple gestation at risk for premature labour • Persistent second or third trimester bleeding • Placenta praevia after 26 weeks gestation • Premature labour during the current pregnancy • Ruptured membranes • Pregnancy induced hypertension

• Severe anaemia • Unevaluated maternal cardiac arrhythmia • Chronic bronchitis • Poorly controlled type I diabetes • Extreme morbid obesity • Extreme underweight (body mass index <12) • History of extremely sedentary lifestyle • Intrauterine growth restriction in current pregnancy • Poorly controlled hypertension/preeclampsia • Orthopaedic limitations • Poorly controlled seizure disorder • Poorly controlled thyroid disease • Heavy smoker

If following symptoms are seen during the exercise, the exercise should be discontinued:

• Vaginal bleeding
• Dyspnoea before exertion
• Dizziness
• Headache
• Chest pain
• Muscle weakness
• Calf pain or swelling (need to rule out thrombophlebitis)
• Preterm labour
• Decreased fetal movement
• Amniotic fluid leakage

Note: warm up and cool down are must before and after exercise and the rating of percieved exertion should be explained to the person.

Physiotherapy in the Management of Gestational Diabetes Mellitus

Exercise is proven to reduce the blood sugar, fasting blood glucose and glycated hemoglobin.

Recent evidence suggests that :

• A program of either aerobic exercise or resistance training appears equally effective, as long as it is performed at least at a moderate intensity or greater, for 20 to 30 minutes, three to four times a week, to provide a repeated stimulus that facilitates improved blood glucose uptake and induces increases in insulin sensitivity.
• The exercise program should suit an individual's preference for the adherence to exercise
• Greater supervision, either face-to-face or via phone follow-up,and use of home-based exercises involving little or no equipment like brisk walking, yoga, resistance exercise with bands are appeared to be associated with higher levels of adherence.
• Exercises given should include large muscle group and less pressure on joints like walking, static cycling, swimming.

Physiotherapy in the Prevention of Gestational Diabetes Mellitus

Regular exercise has shown to prevent the occurence of gestational diabetes mellitus.

• Ming wk, et. al (2018) had concluded that regular exercise (light-to-moderate) for 30–60 min, three times a week, during pregnancy is safe and worthy of promotion in normal-weight women with uncomplicated, single pregnancies. .
• A randomized clinical trial has shown that cycling exercise initiated early in pregnancy and performed at least 30 minutes, 3 times per week, is associated with a significant reduction in the frequency of gestational diabetes mellitus in overweight/obese pregnant women.
• There was a significant reduction in GDM due to higher physical activity.

Some examples to be considered:

1. Exercises that are considered safe:

• Walking
• Swimming
• Stationary cycling
• low-impact aerobics
• Yoga,modified
• Pilates,modified
• Running or jogging
• Racquet sports
• Strength training

2.Exercises that should be avoided:

• Scuba diving
• Sky diving
• Hot yoga or Hot pilates
• Activities with high risk of fall (skiing, off-road cycling, gymnastics, horseback riding)
• Contact sports( ice hockey, boxing, soccer and basketball)

References

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