The pregnant and postpartum stomach

Area of Science:

• Obstetrics and Anaesthesiology
• Gastroenterology
• Medical Imaging

Background:

• Pulmonary aspiration risk is linked to gastric content, lower oesophageal sphincter function, and airway reflexes.
• Pregnancy does not alter basal gastric secretion or acidity.
• Gastric emptying of water is delayed in early pregnancy, but not in later trimesters or postpartum.

Purpose of the Study:

• To review the role of gastric ultrasound in obstetric anaesthesia.
• To guide the interpretation of gastric ultrasound findings in pregnant and non-pregnant women.
• To inform anaesthetic management for caesarean delivery and labour.

Main Methods:

• Review of evidence on gastric emptying in pregnancy and labour.
• Description of gastric ultrasound technique (indication, acquisition, interpretation, management - I-AIM framework).
• Qualitative (Perlas system) and quantitative assessment of gastric contents.

Main Results:

• Carbohydrate drinks and 'Sip Til Send' do not negatively impact gastric antrum size.
• Epidural analgesia in labour improves gastric emptying, but not to non-pregnant levels.
• Gastric ultrasound can identify high-risk stomach contents, influencing anaesthetic choices for caesarean delivery.

Conclusions:

• Clear fluids are likely safe in labour; solid food intake remains a concern.
• Gastric ultrasound is crucial for assessing aspiration risk in obstetric patients.
• Ultrasound findings can guide decisions on postponing caesarean delivery or selecting anaesthetic techniques.