The GI Tract in Pregnancy

• Dramatic anatomical and physiological changes are essential in supporting the nutritional demands of the mother & fetus.

 
• The related alterations are often accompanied by upsets of the GI function & a common cause of complaint with mothers - Often referred to as ` Minor disorders’. 

• Good for biological examination to divide into anatomical and physiological changes to structure your answer plan. 

·Increased appetite - progesterone is a known appetite stimulant

·Cravings or aversions of certain foods.
·Pica – cravings for unusual substances eg. bricks/coal/ic
·Gums may become swollen and bleed easily - results from oedema due to the effects of oestrogen on blood flow & consistency of connective tissue.

·Increase in gingivitis & periodontal disease caused by the oedema (often more extreme with increased maternal age & parity & where there are existing dental problems)

Ptyalism or excess salivation may occur but there is no evidence to suggest that more saliva is actually produced (May be due to some women’s reluctance to swallow if feeling nauseated)

• Heartburn affects 2/3rds of all women at some stage in pregnancy. 

• Due to reflux oesophagitis (acid reflux and inflamation of the lining of the oesophagus) caused by the effect of progesterone on the muscle tone of the cardiac sphincter (between the stomach & oesophagus) 

• The competence of the sphincter is impaired & regurgitation of gastric acid is more likely (acid reflux)

• Also increased risk of hiatus hernia (part of the stomach into the chest through an opening in the diaphram)

• The effect of pregnancy on gastric acid is unclear but may slightly decrease. 

• Gastric muscle tone & motility are reduced and the `emptying time’ of the stomach is affected. 

• During labour, reduced stomach motility leads to a delay in emptying and a risk of acid aspiration. 

• Rantidine given (inhibits stomach acid production)

• Tradition – nutrition whilst in labour 

• Mendelson’s syndrome (The aspiration of stomach contents into the lungs during obstetric anaesthesia)

Progesterone affects the smooth muscle tone of the gall bladder resulting in 

• Flaccidity (lacking firmness)

• Increased bile volume storage 

• Decreased emptying rate. 

• Tendency to form gall stones in pregnancy. 

• Not minor disorder – Cholestasis – raised bile salts (liver condition - causes severe itching)

• No increase in the absorption of food. 

• The transit time of food & waste products through the intestine is prolonged due to reduced mobility & a decrease in the tone of the muscle as a result of the action of progesterone on smooth muscle

• The colon shares in the general relaxation of smooth muscle found throughout the body. 

• Constipation is a common complaint during pregnancy & is made worse by the prolonged transit time of waste materials & the resulting increased absorption of water in the colon. 

• Constipation may also then lead on to the woman developing haemorrhoids (piles)