Bile is one of the vital fluids in the body and was considered as one of the four humors in ancient medicine. It flows from single liver cells through small channels that then converge into larger channels and then into bile ducts. The liver has two small bile ducts called the right and left hepatic ducts that then form the common hepatic duct of the liver. The common hepatic duct then unites with the duct from the gall bladder to form the common bile duct that opens into the small intestines, more specifically into the second part of the duodenum.
Bile is responsible for a wide range of functions. It digests fats and helps in the absorption of fat-soluble vitamins. One of the most important constituents of bile is bilirubin, which is a byproduct of the breakdown of hemoglobin, the main protein of red blood cells. If the flow of bile is impaired, the level of bilirubin rises in the blood, which causes the distinctive yellowish discoloration of the skin and the whites of the eyes known as jaundice.
Pregnancy and the liver
Pregnancy is the most common physiological stress put on the human body, and this physiological stress should pass peacefully, albeit with some changes to the woman’s body. Some changes can be severe enough that they cause disease and can cause problems related to pregnancy that can continue past delivery, and one of the most commonly affected organs is the liver. Most of the changes of pregnancy owe to the hormonal changes that occur during that time. Hormones change the composition of body fluids including bile and can cause an increase in the amount of circulating blood as well.
The most common liver disorder that occurs in pregnancy is intrahepatic cholestasis. The viscosity of bile increases, making its flow slower and simulating an obstruction of the canals. It is important to understand that despite being the commonest liver disorder, it only affects less than 1% of all pregnancies and only occurs in those who are predisposed genetically. In addition, other causes of cholestasis can be extrahepatic such as gallstones. Gallstones are very common in pregnancy, and that is thought to be the result of the increased amount of cholesterol excreted by pregnant women under the effect of estrogen. Estrogen also causes delayed emptying of the gallbladder, causing stagnation of bile and increased stone formation. It is estimated that more than 8 in every 100 pregnant women have gallstones late in the pregnancy. It is indeed more common than intrahepatic cholestasis, but unlike it, it is not related to the liver.