Table 2.

Pre-existing organ involvement or other issues that may impact on the management of pregnancy, labour and delivery.

Issue	Clinical problem	Specific inherited metabolic disease examples
Liver	Adenoma growth	GSD I
	Impaired function	Hepatic GSDs, Wilson disease
Cardiac	Valvular disease	Mucopolysaccharidoses / mucolipidoses
	Impaired ventricular function	Fabry disease, GSD III, mucopolysaccharidoses / mucolipidoses
	Dysrhythmia	Fabry disease, carnitinine transporter deficiency, propionic acidemia
Respiratory	Disordered sleep breathing	Acid maltase deficiency, mucopolysaccharidoses / mucolipidoses, muscle GSDs
	Thoracic deformities	Mucopolysaccharidoses / mucolipidoses
	Narrowed airways – difficult intubation	Mucopolysaccharidoses / mucolipidoses
Orthopaedic	Pelvic / hip / knee involvement	Mucopolysaccharidoses / mucolipidoses / x-linked hypophosphatemia
	Ligamentous laxity	Mucopolysaccharidoses / mucolipidoses
	Spinal involvement / fusion	Mucopolysaccharidoses / mucolipidoses
Endocrine	Thyroid dysfunction	Mitochondrial disorders
	Diabetes	Mitochondrial disorders
Lipid	Hypertriglyceridemia / pancreatitis	Lipoprotein lipase deficiency
Renal	Proteinuria	GSD I, Fabry disease
	Impaired renal function	GSD I, Fabry disease
Muscle	Weakness	Acid maltase deficiency, mitochondrial disorders, some fatty acid oxidation disorders
	Risk of rhabdomyolysis	Fatty acid oxidation disorders
Coagulation	Increased thrombotic risk	Any condition associated with hyperhomocystinemia, e.g. HCU
	Post-partum bleeding	GSD I
Intellectual	Ability to adher to treatment recommendations and care for child	Any metabolic condition associated with severe childhood decompensation (e.g. hyperammonemia, hypoglycemia, encephalopathy) leading to fixed intellectual impairment or progressive neurodegeneration
Medications	Potential impact if medication stopped	In particular for management of epilepsy, hypertension, dyslipidemia