On examination she had a temperature of 37.6°C, pulse 125 beats/min and an inflamed oropharynx. Her abdomen was soft and non-tender with no rash, and the cardiotocograph was reassuring. She was given paracetamol and her temperature and pulse returned to normal. She was sent to accident and emergency for H1N1 testing and sent home.

The following day the swab was positive for H1N1 and the patient was contacted at home. She was noted to have raised aspartate transaminase (AST) and alanine transaminase (ALT). In view of the blood results and the reduced fetal movements, she was admitted and started on nasal (inhaled) zanamivir (Relenza) which she continued for 5 days. On re-admission she had a temperature of 38.8°C and pulse of 120 beats/min. She improved clinically and was investigated for the cause of the raised transaminases.

She remained in hospital for 5 days and improved symptomatically. She was monitored as an outpatient and 13 days after initial presentation the transaminases were once again rising. The results of her investigations are shown in tables 1 and ​and2.2. She had a normal vaginal delivery of a boy weighing 2.794 kg on day 14. Mother and baby were well and discharged the next day. She has continued to be monitored including liver function testing which has shown a return to normal of transaminases.

Patient 2 was seen at the same time, complaining of itching for a week at 34+2 gestation. She was investigated and was found to have raised transaminases but also raised bile acids of 11 μmol/l (reference range 1–10 μmol/l) (table 3). She had been treated for H1N1 infection with zanamivir 2 weeks before. She continued to have liver function testing and was managed as having obstetric cholestasis, although repeat bile acids on 10/07 was normal at 5 μmol/l. Repeat transaminases on 04/09 had returned to normal (table 3).

The cytomegalovirus IgM was equivocal and of uncertain significance.

In both our cases the patients responded to antiviral medication. Currently many cases of H1N1 infection are treated without hospital admission and blood tests. Patient 1 had liver function tests as part of a sepsis screen and patient 2 required testing as she had symptoms of obstetric cholestasis. In both patients the transaminases were significantly raised without a rise in bilirubin. In patient 1, as she was an inpatient and had serial blood tests, we were able to see that the concentrations dropped while on antiviral medication but then increased again. This transient transaminase rise did not seem to have an adverse effect on the patient and caused no problems for the fetus, but did lead to early induction of labour. In patient 2, the rise was thought to be due to obstetric cholestasis as the bile acids were also slightly raised; however, the repeat value was normal and the transaminase concentrations returned to normal following delivery.

We will need to observe extra caution in pregnant patients who present with flu like symptoms and commence antiviral treatment early to reduce severity of symptoms. We also need to consider whether monitoring of liver function should be done routinely in pregnant women who contract the H1N1 virus.