A woman who had contracted swine flu died shortly after giving birth prematurely, it was reported.
The woman, who died in Whipps Cross Hospital, was named by her brother as Ruptara Miah. She is thought to be from Bangladesh.
Abdul Malik told BBC News his sister had used a wheelchair for 15 years after a road traffic accident but had led a normal life and had brought up six daughters.
"We are very, very upset as a family. It has really taken me by shock," he said. "We thought she was going to recover."
His sister, the eldest of 10 children, was admitted to hospital three weeks ago with a cough and chest infection, he said.
She was treated in intensive care, where she gave birth to a son prematurely, but never regained full consciousness, he added.
The baby is now in intensive care, according to reports.
A spokesman for Whipps Cross said: "Whipps Cross University Hospital NHS Trust can confirm that a 39-year-old woman passed away on July 13, 2009, and that she was infected with pandemic H1N1.
"The trust can confirm that she had underlying health conditions. No further comments can be made at this time."
An NHS Bedfordshire spokesman said last night that swine flu was a "significant contributory factor" in the death of Bedfordshire GP Dr Michael Day. Dr Day, 64, died on Saturday in the Luton and Dunstable Hospital.
Earlier this week it emerged that a post-mortem examination had established that Dr Day died from natural causes.
It was announced yesterday that schools could be forced to stay closed after the summer break if the swine flu pandemic escalates.
While the Government expects schools and nurseries to open as usual in the autumn, the Department for Children, Schools and Families (DCSF) said it "cannot be certain what the situation will be".
About 1,000 schools have already recorded cases of swine flu, the DCSF said in its guidance to teachers, though most have managed to stay open.
The Department said it was looking at the situation on a day by day basis and would be monitoring developments over the summer.
A message will be sent to schools in the last week of August informing them of what to do at the start of term.
The DCSF statement said: "We expect that schools and early-years and childcare settings will reopen as usual, but at this time, we cannot be certain what the situation will be then."
A planning document published by the Department of Health suggests that if the current growth in cases is sustained, there could be a peak in the flu pandemic in early September, with up to 30% of the population experiencing symptoms.
But it is possible it could begin to slow down over this month and next, before a resurgence in autumn, when schools reopen.
The total number of deaths linked to swine flu now stands at 29 in the UK, including four deaths in London reported on Thursday.
Ten people have died in the capital and NHS London is investigating another three to see if they were also linked to the virus.