Liver Disease in Pregnency
Obstetric Cholestasis
This liver disease is specific to pregnancy, characterized by pruritus affecting the whole body but particularly the palms & soles, & abnormal liver function tests.
Aetiology is unknown but relate to genetic predisposition (one third of patients have positive family history) to the cholestatic effect of estrogen.
It is most commonly present in the third trimester (30-32 weeks). Women with pruritus but without rash other than excoriation should have liver function test. Hepatic transaminases are only mildly elevated. Bile acids may be elevated. There may be associated dark urine, pale stool, steatorrhea & malaise.
Obstetric cholestasis is a diagnosis of exclusion & differential diagnosis include extrahepatic obstruction with gall stones, acute & chronic viral hepatitis, primary biliary cirrhosis & chronic active hepatitis.
Investigations should therefore include liver ultrasound, serology for hepatitis A, B, C, Ebstien-Bar virus & cytomegalovirus, & liver autoantibodies (anti- mitochondrial antibodies, & anti-smooth muscle antibody).
The risks with obstetric cholestasis include postpartum haemorrhage (related to vitamin K deficiency secondary to malabsorption of fat), premature labour, meconium-stained liquor, fetal distress in labour & rarely intra-uterine death.
Management:
should involve counselling the woman regarding the above risks. LFT & clotting time should be monitored regularly. In the absence of premature labour, delivery should be induced at 37-38 weeks. Vitamin K should be given to the mother (10 mg orally daily) from the time of diagnosis to reduce the risk of postpartum haemorrhage. Fetal surveillance with CTG & ultrasound provide reassurance.
Control of symptoms may be achieved with a combination of antihistamines & emollients or, if no response ursodeoxycholic acid will induce a rapid reduction in liver function test & pruritus but not the fetal risk.
Following delivery, LFT returns to normal. Symptoms may recur with menstruation (cyclical itching) or with estrogen containing oral contraceptives which should be avoided. Recurrence in subsequent pregnancy is very high.
Acute Fatty Liver of pregnancy:
This is another pregnancy specific liver disease which is rare. AFLP is closely related to pre-eclampsia. It usually presents in the third trimester with abdominal pain, nausea, vomiting, anorexia & sometimes jaundice.
The aetiology is unknown but histologically perilobular fatty infiltration of liver cells is noted. Following the onset of the condition, there is a rapidly worsening cascade of problems. It is associated with markedly deranged LFT, renal impairment, raised uric acid, raised white blood cells, hypoglycaemia & coagulopathy.
Perinatal & maternal mortality & morbidity are increased. Maternal death result from hepatic encephalopathy or overwhelming haemorrhage associated with clotting defect.
Management:
Should involve intensive care unit & multidisciplinary team. Delivery should be expedited following correction of hypoglycaemia or coagulopathy with 50% dextrose, vitamin K & fresh frozen plasma.
Management after delivery is conservative. Referral to liver unit is indicated if liver function still abnormal or there are features of hepatic encephalopathy
.
Viral Hepatitis & Pregnancy:
Viral hepatitis is the most common cause of jaundice in pregnancy. None of the hepatitis viruses are known to be teratogenic. The course of most viral hepatitis infections (e.g., hepatitis A, B, C and D) is unaltered by pregnancy except with hepatitis E which exhibit markedly increased fatality rates.
Treatment: Certain patients may benefit from pharmacologic therapy for chronic HBV and chronic HCV infections in particular. Current approved therapy for HCV-related chronic liver disease includes alpha interferon alone or in combination with the oral agent ribavirin. Interferon does not have an adverse effect on the embryo or fetus while the use of ribavirin during pregnancy is presently contraindicated.
Post-exposure Prophylaxis for Susceptible Pregnant Women: HBV immunoglobulin, HAV vaccine, and HBV vaccine all currently are approved for use during pregnancy.
If Exposure to Persons Who Have Acute Hepatitis B, a course of HBV vaccine & Hepatitis B immune globulin (HBIG)
Vertical Transmition:
HAV is not transmitted to the fetus in utero but may be transmitted to the neonate during delivery or during the postpartum period (fecal-oral route). The risk of HBV vertical transmission is 10% in mothers with negative HBeAg and positive HBeAb while it is 90% in those with positive HBeAg. Neonatal HBV infection increase with increasing gestation. Universal screening of pregnant women for HBsAg is performed to reduce perinatal transmission of hepatitis B virus.
Neonatal prophylaxis
Infants of HBsAg-positive mothers should receive hepatitis B immune globulin immunoprophylaxis at birth and hepatitis B vaccine at one week, one month and six months after birth. This regimen reduces the incidence of hepatitis B virus vertical transmission to zero to 3 percent
Delivery: Delivery by cesarean section for the purpose of reducing transmission is not recommended. Intrapartum fetal scalp electrode & fetal blood sampling should be avoided. If instrumental delivery is needed, forceps rather than ventouse is appropriate.
With appropriate hepatitis B immunoprophylaxis, breast-feeding poses no additional risk for maternal to child transmission.