Diabetes during pregnancy Flashcards
What is the pathophysiology of GDM?
GDM occurs when the body is unable to produce enough insulin to meet the needs of the pregnancy. Insulin is responsible for the uptake of glucose in the blood and its storage as glucagon.
During pregnancy there is insulin resistance which means a higher level of insulin is needed in response to a normal glucose level. average 30% rise in insulin requirements.
In a woman with a borderline pancreas reserve this may result in transient diabetes which resolves when the pregnancy insulin resistance is over and they return under the cut offs.
What are the risks of GDM/ borderline pancreas reserve?
BMI >30
Asian ethnicity
Previous gestational diabetes
1st degree relative with diabetes
Polycystic ovarian syndrome
Previous macrosomic baby (>4.5kg)
age >40
on long term steroids for IBD, asthma etc
What are the clinical features of GDM?
Most women with a borderline pancreatic reserve will be asymptomatic, and will show no signs of gestational diabetes.
If present, the clinical features tend to be the same as other forms of diabetes – i.e. polyuria, polydipsia and fatigue.
What are the fetal complications of GDM?
- during pregnancy maternal glucose can cross the placenta but insulin cannot so if there is increased glucose in the mother it will be too in the fetus and the fetus will have to produce extra insulin to balance this = fetal hyperinsulinemia.
Insulin is a hormone that has a similar structure to growth promotors, and it therefore causes:
Macrosomia – this can cause complications during labour, such as shoulder dystocia, obstructed/delayed labour, and/or higher rates of instrumental deliveries.
Organomegaly (particularly cardiomegaly)
Erythropoiesis (resulting in polycythaemia)
Polyhydramnios
Increased rates of pre-term delivery
After delivery, the fetus still has high insulin levels, but no longer receives glucose from its mother. This results in an increased risk of hypoglycaemia – and therefore regular feeding is important.
Additionally, high insulin can cause a reduction in pulmonary phospholipids, which in turn decreases fetal surfactant production. Surfactant acts to reduce the surface tension in alveoli (thus aiding gas exchange), and these babies are at risk of transient tachypnoea of the newborn.
Maternal complications of GDM?
- Pre-eclampsia x2
- Preterm labour
- Birth injuries such as perineal tare; SD, etc
Investigations for GDM?
In Ireland it is mainly only screened for those with risk factors. Screening at booking (if Hx), at 28 weeks, or whenever glycosuria is detected
* If >6mmol/l fasting or >7mmol/l postprandial => OGTT
Diagnosing GDM : Rotunda Hospital (IADPSG Criteria) at 24 – 28 weeks’ gestation
Fasting : > 5.1 mmol/l
1 hour post prandial : > 10.0 mmol/l
2 hour post prandial : > 8.5 mmol/l
Mgmt of GDM?
The aim of treatment is to provide good glycaemic control for the duration of the pregnancy. Lifestyle advice should be given regarding diet and exercise – as this alone can sometimes be sufficient. Capillary glucose measurements should be taken four times a day.
The medical management of gestational diabetes involves careful monitoring and control of blood glucose. The medications used to reduce blood glucose include:
Metformin – suitable in pregnancy and breast feeding.
Glibenclamide – used if metformin is not tolerated (often due to GI side effects) and insulin has been declined.
Insulin
Consider starting at diagnosis if the fasting glucose >7.0mmol/L.
Or introduce later in pregnancy if
(i) pre meal glucose > 6.0mmol/L
(ii) post meal glucose >7.5mmol/L
(iii) fetal AC (abdominal circumference) >95th centile
every 2 week US & fetal wellbeing, every week after 34 wks. weight BP proteinuria.
What gives an idea of long term control in preg?
fructosamine & glycosylated Hb
When should GDM be delivered?
if diet controlled and no complications: as normal - 41 weeks
if well controlled with meds - 39 wks
if poorly controlled - earlier as indicated
IV dextrose & insulin during delivery
continuous CTG
NB if slow progression worry about cephalopelvic disproportion
What are the anti-insulin hormones?
hCG, progesterone, human placental lactogen, cortisol
Postnatal care of GDM?
All anti-diabetic medication should be stopped immediately after delivery. The blood glucose should be measured before discharge to check that it has returned to normal levels.
Around 6-13 weeks post-partum, a fasting glucose test is recommended. If this is normal, yearly tests should be offered because of the increased risk of developing diabetes in the future (50% of mothers with gestational diabetes will go onto develop Type 2 Diabetes in later life).
In subsequent pregnancies, an OGTT should be offered at booking and at 24 – 28 weeks’ gestation.
Examination in GDM?
IMEWS
* BMI
* SFH >dates (Macrosomia, polyhydramnios)
* Urinalysis –glucose, protein, ketones
Examinations in T1DM in pregnancy?
IMEWS
* SFH
* >date –macrosomia, polyhydramnios
* <date —renal disease, superimposed PET
* Injection/pump site, feet
* Urinalysis –glucose, protein, ketones
Complications of T1DM in pregnancy?
- Congenital anomalies
- CNS –anencephaly, spina bifida
- Cardiac –VSD, Transposition of great vessels, Hypoplastic left heart
- Renal –Agenesis
- Skeletal –Caudal regression
- GI –Anal Atresia
- Macrosomia
- Polyhydramnios
- Shoulder dystocia * DKA
Mgmt of T1DM in preg?
Seen pre-conception
* Tight glycemic control 4-6mmol/L
* Increase insulin injection frequency
* Increase blood glucose monitoring
* Continuous SC insulin pump
* Check for nephropathy, retinopathy, and neuropathy
* Pre-conceptual folic acid 5mg/day
* Specialist diabetic clinic
* Multidisciplinary care
* 20-week anatomy scan
* 22–24-week fetal echo
* Delivery –good control at 39 weeks, earlier with poor control, later with diet control
* IV dextrose and insulin during delivery
* Postnatally goes back pre-pregnancy insulin levels§
