DIABETES MELLITUS IN PREGNANCYIzyan Mohammad

DEFINITIONSDiabetes Mellitus in Pregnancy falls into 2

categories:

1. Gestational Diabetes Mellitus (GDM) – Any degree of glucose intolerance with onset or first recognition during pregnancy. Does not exclude possibility that unrecognised glucose intolerance may have been present before onset of pregnancy.

2. Pre-gestational Diabetes Mellitus – diagnosed when the woman has diabetes before pregnancy.

GESTATIONAL DIABETES MELLITUS (GDM)

Physiology Pregnancy ↑ HPL + cortisol (insulin antagonists) Mother relative insulin resistance esp 3rd trimester Maternal pancreas ↑ insulin to maintain

carbohydrate metabolism ↓ FPG Carbohydrate intake ↑ glucose than non-pregnant

lady

Glucose crosses placenta by facilitated diffusion and the fetal blood glucose level closely follows the maternal level

Therefore, fetal glucose levels therefore is normally maintained within normal limits, as in mother.

Modified Penderson Theory: Impact of Maternal Hyperglycaemia During Pregnancy

MATERNAL PLACENTA FOETAL

↓ Insulin release

↓ glucose utilisation

Hyperglycaemia Hyperglycaemia

↑ Insulin(hyperinsulinaemia)

Birth weight ↑

↑ Lipid & ↑ Glycogen? Altered structure

and/or function

GDM IN FIRST TRIMESTER Women found to have fasting

hyperglycaemia or abnormal glucose intolerance in the first trimester might have pre-existing diabetes

Should be treated as women with glucose intolerance before pregnancy

First trimester hyperglycaemia high risk of congenital abnormalities in foetus

SCREENING FOR GDM Women with high risk of GDM:

BMI >30kg/m2

First degree relative with Diabetes Personal history of GDM Previous macrosomic baby ≥4.5kg Family origin with high diabetes prevalance

(South Asian, African-Caribbean, Middle-Eastern) *Previous poor obstetrics outcomes usually

associated with diabetes

PRE-GESTATIONAL DIABETES

TYPE 1 AND TYPE 2 DIABETES Pre-conception care is essential If untreated in first few weeks gestation,

associated with: Spontaneous abortions Birth defects

If untreated during 2nd or 3rd trimester, associated with: Foetal macrosomia and metabolic abnormalities Birth injury Maternal hypertension and pre-eclampsia Future diabetes and/or obesity in child

PRE-PREGNANCY COUNSELLING To assess suitability for pregnancy To look for complications of diabetes,

evaluate and treat complications prior to onset of pregnancy

To achieve optimal control prior to and during very early pregnancy

To provide an opportunity for pre-pregnancy advice and folate supplements

MEDICAL ASSESSMENT IN PRE-CONCEPTION CARE Duration and type of diabetes Medical history and current medical

management plan Chronic diabetes complications:

Retinopathy Nephropathy Neuropathy

Co-morbid conditions (in addition to diabetic complications) Hypertension (ideal blood pressure <120/80) Coronary Artery Disease Hyper- or Hypothyroidism Other auto-immune disease

PREVENTING RETINOPATHY PROGRESSION

Rapid normalization of blood glucose during pregnancy can trigger retinopathy progression

Retinal status should stabilized prior to conception

Reassess retinal status each trimester (more frequently if retinopathy is present)

RECOMMENDATIONS Plan pregnancies Attain a pre-conception HbA1c of < 7% If planning pregnancy:

Needs retinal screening prior to conception Screen for diabetic retinopathy and coronary

heart disease Discontinue oral hypoglycaemic agents and

attain glycaemic targets using insulin, if possible Replace ACEI and ARBs to other hypertensives

that are safe to take in pregnancy Stop statins

POSSIBLE CONTRA-INDICATIONS TO PREGNANCY Ischaemic Heart Disease Active, unrelated proliferative retinopathy Renal insufficiency Severe Gastroparesis

Inability or unwillingness to use Insulin

RISKS TO MOTHER WITH GESTATIONAL DIABETES Increased risk of Caesarian Section Pre-eclampsia (2-4 x esp with co-existing

microalbuminuria/frank nephropathy) Polyhydramnios Pre-term labour Post-Partum Haemorrhage Temporary worsening of renal function Progression of retinopathy ↑ incidence of infection, severe

hyperglycaemia/hypoglycaemia, DKA In future:

Recurrent GDM Pregnancies Risk of developing T2DM (50% in 5 - 10 years)

POTENTIAL COMPLICATIONS IN INFANTS OF MOTHERS WITH DIABETES

Intra-uterine demise Spontaneous

abortions Stillbirth (10-30%)

Congenital malformations Neural tube defects Cardiac defects Caudal Regression

syndrome (rare)

POTENTIAL COMPLICATIONS IN INFANTS OF MOTHERS WITH DIABETES Macrosomia Visceromegaly

Cardiac enlargement Hepatic enlargement

Respiratory Distress Syndrome

Asphyxia Birth injury

Shoulder Dystocia Erb’s Palsy Diaphragmatic

paralysis Facial paralysis

MACROSOMIA

POTENTIAL COMPLICATIONS IN INFANTS OF MOTHERS WITH DIABETES Metabolic complications

Hypoglycaemia (high insulin production in immediate neonatal period due to recent foetal hyperglycaemia) Mothers encouraged to breastfeed ASAP; monitor

baby’s blood glucose; formula-fed or glucose infusion prn

Hypocalcaemia, magnesium deficiency apnoeic episodes and fits

Polycythaemia hyperbilirubinaemia jaundice Partial exchange transfusion

Management: Obstetrics Nuchal Traslucency Scan Detailed US for foetal anomalies Foetal echocardiography Serial growth scan Monitor foetal well-being (doppler US & CTG) Aim: vaginal delivery between 38 – 40 weeks 50% Ceasarian section because of

macrosomia, pre-eclampsia and failed induction of labour

Management: preterm labour & polyhydramnios Difficult Tocolytics (e.g. ritodrine, salbutamol) are

diabetogenic I/M steroid for foetal lung maturation

destabilize diabetic control I/V insulin / glucose infusion if required to

ensure normoglycaemia

Management: Intrapartum Induced/Spontaneous labour sliding scale

of insulin to maintain normoglycaemia Test maternal blood glucose hourly Continuous foetal monitoring advised Foetal scalp blood sampling if CTG abnormal

Management: Post-delivery Insulin requirements return to pre-pregnant

levels If GDM, stop insulin OGTT 6/52 post-delivery to ensure diabetes

has resolved

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