• Findings overturn earlier research on working mothers
• Gains of being in employment outweigh disadvantages

A ground-breaking study has found that mothers can go back to work months after the birth of their child without the baby's wellbeing suffering as a result.

By assessing the total impact on a child of the mother going out to work, including factors outside the home, American academics claim to have produced the first full picture of the effect of maternal employment on child cognitive and social development. Their conclusion will provide comfort for thousands of women who re-enter the employment market within a year of giving birth.

"The good news is that we can see no adverse effects," said American academic Jane Waldfogel, currently a visiting professor at the London School of Economics. "This research is unique because the question we have always asked in the past has been: 'If everything else remains constant, what is the effect of a mum going off to work?' But of course everything else doesn't stay constant, so it's an artificial way of looking at things.

"Family relationships, family income, the mental health of the mother all change when a mother is working and so what we did was to look at the full impact, taking all of these things into account."

In one of the most fraught areas of social policy and research, several studies over the past two decades have suggested that children do worse if their mothers go back to work in the first year of their lives.

Recent research by the Institute for Social and Economic Research at Essex University found that children of mothers who went back to work within the first three years were slower learners, and a 2008 Unicef study recommended that mothers stay at home for the first 12 months or "gamble" with their children's development. The Pew Research Centre in Washington found high levels of anxiety among women over the issue.

The new study, led by New York's Columbia University School of Social Work, was published last week by the Society for Research in Child Development. The National Institute of Child Health and Human Development Study of Early Child Care followed more than 1,000 children from 10 geographic areas aged up to seven, tracking their development and family characteristics.

It found that, while there are downsides to mothers taking work during their child's first year, there were also significant advantages – an increase in mothers' income and wellbeing, and a greater likelihood that children receive high-quality childcare. Taking everything into account, the researchers said, the net effect was neutral.

"The effect of the parenting itself is the key factor," said Waldfogel. "It is hugely important how sensitive you are to your child's needs. Even for women who have to work more than 30 hours a week, they can make things better for themselves, they just need to take a deep breath on the doorstep, dump all the office worries behind them and go in the door prepared to pay attention to all their children's cues. This is good news for all mothers.

"I'm actually delighted to have been able to disprove earlier studies. We just had to ask some different questions and this approach of looking at the whole picture is definitely the right question to be looking at.

"This is especially good news for US mothers, who typically go back to work after three months because of the lack of maternity leave, but it equally will apply to the typical British family."

Waldfogel added that part-time work, up to 30 hours a week, provides more desirable outcomes than full-time employment. The authors attribute their striking findings to the rich data used in the study, detailing parent-child interactions, income and childcare. They also used an analytic method that allowed them to calculate the total effect of maternal employment taking into account all knock-on effects.

Parents and campaigners welcomed the findings. Siobhan Freegard, co-founder of the parenting website Netmums, said the results would be embraced by every working mother, and pointed out that many women had no choice but to work and their attitude was often "we are doing our best".

Sally Gimson, director of communications at the Family and Parenting Institute, said the quality of childcare was crucial. "Women should not feel guilty whatever choices they make – and that does not mean you have to make the choice to work. Often it is the more well-off women who have the choice, while many others have to work," Gimson said.

Sam Willoughby, 37, wanted to go back to her job at a financial services company part-time after having her daughter, Alice. "But they were incredibly inflexible," she said. She decided not to return and now runsmumandworking.co.uk, which aims to help mothers find flexible options, both full- and part-time. "So many things make working mothers feel awful, but the reality is, as this study shows, that going back to work is acceptable.

"There is a notion that mothers should spend all their time with their children but that is wrong. You need to also do things that are just for you. And a career can give you that."

Julie Wilson, 43, returned to work full time when her first son, James, was six months old. "We had a really good nursery nearby and it was absolutely fine. I really enjoyed my job and never considered changing my hours. I don't feel he missed me – he was happy at nursery. He was occupied all the time… Later on it was really educational."

When her second son, Ben, was born, she returned to work again, but went part-time. Wilson, who now works as a freelance, thinks the decision to work had no negative impact on the boys, now 12 and eight. "Looking at James now, he is a very rounded individual."

Yousaf Raza Gilani's comments follow cancellation of trip to Britain by Pakistan's spy chief

Pakistan's prime minister hit back today at remarks by David Cameron linking the country to the export of terrorism.

Yousaf Raza Gilani, the normally conciliatory premier, used a speech to make the highest level response from Islamabad so far to Cameron's comments during his trip to India. Reports suggest that an official from the British high commission in Islamabad, possibly the deputy chief of mission, will be summoned tomorrow by Pakistan's ministry of foreign affairs for a formal dressing down.

Gilani's intervention follows the abrupt cancellation by Pakistan's spy chief, General Shuja Pasha, of a planned visit to the UK for talks with his British counter-terrorism counterparts.

Co-operation from the Inter-Services Intelligence (ISI) agency, headed by Pasha – which was accused of aiding the Taliban in the Afghan war logs published last week by WikiLeaks – had previously been presented as being crucial to stopping numerous terrorist plots aimed against Britain.

There are fears that a long-planned visit to the UK this week by Pakistan's president, Asif Zardari, could be overshadowed by growing anger at Cameron's remarks among the one million people of Pakistani origin living in Britain. Media outlets and opposition politicians in Pakistan are urging the president to cancel the trip, while demonstrators burnt an effigy of the prime minister on the streets of Karachi.

There is particular anger, shown by Pakistanis yesterday in burning an effigy of the prime minister, that Cameron made the comments on a trip to India.

Gilani focused on the issue in today's speech in Punjab province. "In India, he [Cameron] has given a statement that we in Pakistan promote terrorism," he said. "We want to say to him, we've had good relations with you for 60 years."

He contrasted the issue raised by Cameron with the situation in Kashmir, the Himalayan region mostly held by India, which has been in open rebellion for 20 years. "In India, you [Cameron] talk about terrorism but you don't say anything about Kashmir. You forgot about the human rights abuses going on there. You should have spoken about that too, so that we in Pakistan would have been satisfied."

While Pakistan has frequently been asked to do more in the battle against extremists, Cameron's remarks are seen in Pakistan as going further than any western leader in criticising the country's record and commitment.

An editorial in Dawn, Pakistan's leading English-language daily, said: "No one, with the exception perhaps of New Delhi and Kabul, had ever accused Pakistan of exporting terrorism. In doing so, was Mr Cameron attempting to bracket Pakistan with countries that have been or still are anathema to the west?"

An officer at the ISI said: "Do you make such remarks when visiting a third country, a country we consider an enemy? It was done to appease [India]. You can sit in England and say what you want, but sitting in India gives it a completely different connotation."

A senior Pakistani civilian official said: "Cameron's remarks show a political immaturity, lack of foreign policy experience – and talk about a choosing a bad venue to deliver the message. Being the youngest British prime minister in two centuries isn't necessarily an advantage."

The Cameron intervention came as Pakistan was reeling from the disclosures in the US intelligence documents made public by WikiLeaks. The apparent evidence of ISI collusion with the Taliban from the WikiLeaks material had already been seized on with glee by Indian officials, as confirmation of New Delhi's charge that the Pakistani state sponsors terrorism.

The shadow foreign secretary, David Miliband, said: "Diplomacy is about making friends and influencing them. Today's announcement by the ISI sadly proves that Cameron has failed to make friends and failed to influence them. We need to support Pakistan's intelligence services, not undermine them – their work protects the people of Britain as well as the people of Pakistan. We have a strong Pakistani community in Britain and we have troops in Afghanistan – the stakes are simply too high to go hunting headlines with thoughtless remarks.

"We need a prime minister that understands the complexity of diplomacy and so far Cameron has failed to prove himself as the standard-bearer we need around the world."

Travel expert Riaz Dooley, who has worked to encourage British Asians to take a greater interest in political life, warned that Cameron risked alienating British-Pakistanis. He said: "David Cameron is going to lose the Pakistani vote over this, because he has not apologised. It is not fair to say that Pakistan promotes the export of terrorism, he doesn't have any proof."

Labour MP Khalid Mahmood agreed that the Pakistani community in the UK was angry about Cameron's comments. He said the prime minister had failed to reflect how much the country had sacrificed in the war on terror. "They have taken a huge amount of casualties in the north-west province and there have been a huge number of bombings in Pakistan.

"They have suffered enormously in terms of their own people's lives and to suggest this counts for nothing is very, very insensitive."

Julian Assange defends the whistleblowers' website after its publication of 75,000 leaked files of US army secrets

WikiLeaks founder Julian Assange has hit out at the US military, saying that it bears the ultimate responsibility for any deaths of Afghan informers in the wake of the publication by his organisation of 75,000 leaked files of American army secrets.

Assange and WikiLeaks, the whistleblowers' website that publishes leaked documents from around the world, have come under increasing fire amid accusations that publishing the files put people's lives at risk. But in an interview with the Observer, Assange said the blame for any deaths lay squarely with US military authorities.

"We are appalled that the US military was so lackadaisical with its Afghan sources. Just appalled. We are a source protection organisation that specialises in protecting sources and have a perfect record from our activities," he said.

WikiLeaks has been accused of disclosing the names of Afghan collaborators who may now be subject to reprisals. Critics also say that the information it published is unchecked and some of it may be of dubious provenance. But Assange responded to those claims by saying: "This material was available to every soldier and contractor in Afghanistan… It's the US military that deserves the blame for not giving due diligence to its informers."

Assange insisted there was no evidence that anyone had been put at risk and that WikiLeaks had held sensitive information back and taken great care not to put people at risk. "Well, anything might happen, but nothing has happened. And we are not about to leave the field of doing good simply because harm might happen… In our four-year publishing history no one has ever come to physical harm that we are aware of or that anyone has alleged."

However, he did concede that, if it was proven someone had been killed or injured because of the leak, then WikiLeaks would consider changing the way it operates. "We will review our procedures," he said. But that is unlikely to defuse the growing international row. Last week the Afghan president, Hamid Karzai, branded Assange "irresponsible". The US defence secretary, Robert Gates, said he might have "blood on his hands".

At the same time US authorities are broadening their investigation into how the leak happened. The suspected leaker, Private Bradley Manning, is in custody. He has already been charged with passing on a video shot in Iraq of a US helicopter attack and 150,000 classified diplomatic cables. He is also the main suspect in the Afghan "war logs" leak. Now, according to a report in the New York Times, investigators are probing whether Manning acted alone or with others. The focus of the inquiry was on a group of people in Cambridge, near Boston in Massachusetts, who might prove to be the link between Manning and WikiLeaks.

Assange said he was undeterred by the attacks, and that traditional journalism had vacated a space into which WikiLeaks was stepping. "We are creating a space behind us that permits a form of journalism which lives up to the name that journalism has always tried to establish for itself," he said.

AP - The death toll in the massive flooding in Pakistan surged past 800 as floodwaters receded Saturday in the hard-hit northwest, an official said. The damage to roads, bridges and communications networks hindered rescuers, while the threat of disease loomed as some evacuees arrived in camps with fever, diarrhea and skin problems.

AP - A wildfire smoldered in the high desert north of Los Angeles Saturday, spewing plumes of thick smoke into a nearby town as hundreds of firefighters worked to contain the 2-day-old blaze.

AP - Chelsea Clinton was poised to marry her longtime boyfriend at an exclusive estate along New York's Hudson River after weeks of secrecy and buildup that had celebrity watchers flocking to the small village for the Saturday evening nuptials.