Obstetric Cholestasis (OC) or Intraheptic Cholestasis of pregnancy is a disorder that is unique to pregnancy (Kelly and Nelson-Piercy, 2000).OC classically presents in the third trimester (Royal College of Obstetricians and Gynaecologists [RCOG], 2006), With maternal pruritus and raised bile acids (Geenes and Williamson, 2009).It is one of the few disorders of pregnancy that can affect both maternal well being and fetal outcome. OC usually resolves forty eight hours after delivery (Mays, 2010).
This essay will examine the functions of the liver and discuss the role of bile acids in OC. The pathophysiology of OC will be explored. The role of the midwife within a multidisciplinary team, alongside the physical care that is offered to women suffering from OC will be discussed. Finally the use of fetal surveillance to predict and prevent fetal demise will be evaluated. A case study will be referred to throughout this essay (see appendix 1) and in strict adherence to the Nursing and Midwifery Council (NMC) 2008 guidelines on patient confidentiality, the woman shall be known as Jacinta, a Gravida 2 Para 1 who presented with OC at 24/40 weeks gestation and was delivered by caesarean section at 37/40 weeks.
The structures of the body involved with OC are the liver and the gallbladder. Bothamley and Boyle, (2009) describe the liver as the most important metabolic organ. The liver is responsible for the metabolism of carbohydrates, fats .lipids and proteins, previously absorbed in the digestive tract (British Liver Trust 2006).Protein metabolism involves the breakdown of cells to form uric acid which is excreted in urine (Wylie and Bryce, 2008). The liver synthesisizes plasma proteins, and most of the blood clotting factors occurs within the liver. The liver detoxifies drugs and other noxious substances, and is involved with the secretion of bile.
Bile is a thick alkaline substance composed of water, mineral salts, mucus, bilirubin, bile salts, electrolytes and cholesterol (Wylie, 2000). Bile salts are conjugated bile acids synthesized in the liver from cholesterol. Their main function is to breakdown fat which aids digestion and the absorption of lipids (Coombes, 2000). Increased metabolic demands in pregnancy can cause diminished capacity of the liver to absorb or excrete bile (Bothamley and Boyle,2009); resulting in bile acids that are usually excreted, being retained within the liver cell membrane, causing partial damage or total destruction of the hepatocytes membrane. Leading to structural changes within the hepatic circulation enabling high levels of bile acid to accumulate in the blood (Geenes and Williamson, 2009), which triggers a release of histamine causing pruritus (Saleh and Abdo, 2007).
The pathophysiology of OC is complex and not fully understood, however it is generally agreed to be multifactorial with genetic, environmental and hormonal influences (Miliewicz et al, 2002, Lammert, Marschall, and Marten, 2003).Evidence to support a genetic link includes a high prevalence amongst Chilean and Scandinavian women (Bruce and Watson 2007).Two of Jacinta’s sisters suffered with OC during their pregnancies and indeed genetic studies have discovered a family history in 33-50% of women diagnosed with OC (Dixon and Williamson, 2006).There have also been suggestions of an autosomomal dominant inheritance pattern (Fagan 2000,Kelly and Nelson-Piercy , 2000). During pregnancy higher levels of oestrogen and progesterone occur and these higher levels have been implicated as hormonal triggers for the development of OC (Mays, 2010). Oestrogen levels are highest in the third trimester (Geenes and Williamson, 2009) and may explain why the symptoms of OC typically present during this period. A deficiency in selenium has been identified as a possible environmental factor (Geenes and Williamson, 2009).Some studies associate seasonal variations in the consumption of vegetables containing selenium with the development...
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