Young people are so attached to their mobile phones, notes Nursal Livatyali, that it's as though they're an extra body part. "We know that anything you send to them through their mobiles will be received."

That is why in Enfield, north London, where Livatyali is the teenage pregnancy co-ordinator (TPC), young people wanting advice about sex, contraception and relationships can text questions to a free service for an answer within half an hour.

Providing advice on sexual health is key to cutting teenage pregnancy rates, as is giving girls the confidence to insist on contraception and not to feel pressured into sex. And a scheme in Enfield where boys and girls spend Wednesday afternoons at a nursery paired with a toddler not only gives them a realistic taste of how much work babies are, but also boosts their aspiration and self-esteem.

Advisers have to make sure work is targeted at those most at risk: Livatyali has commissioned two sexual health outreach nurses to phone or text every teenager who has had an abortion to discuss contraception.

Experts in the field say it is work like hers – and other TPCs, who bring together the work of local authorities, primary care trusts (PCTs) and voluntary sector services – that has helped bring about a long sought-after turnaround in the levels of teenage pregnancy in England (the highest in western Europe).

Earlier this year, data from the Office for National Statistics showed that in 2009 – it takes two years for the figures to come through – the conception rate among women aged between 15 and 17 was 38.2 per 1,000. It was estimated to be the lowest rate since the early 1980s, representing a fall of almost 6% on the year before, when the figure was 40.7 per 1,000 women. In Enfield, the rate fell from 55.4 in 2006 to 38.5 in 2009.

The decline is far short of the Labour government's pledge to halve the teenage pregnancy rate from 46.6 conceptions per 1,000 by 2010, but for those involved in Labour's 10-year strategy it was still a triumph.

But with a new coalition government in place, the teenage pregnancy strategy ended and nothing to replace it, and severe cuts to local authority budgets due to bite, there were fears that the crucial role of the TPC would be lost across the country.

Six months after the teenage pregnancy figures were released, a SocietyGuardian investigation has revealed that those fears were well-founded. TPCs have been cut in just over a third of areas – including several where conception rates among under-18s are very high.

A survey of all 150 local authorities in England and those PCTs which employ a TPC discovered that since the beginning of last year the role had been axed in 56 areas. Despite having being among the top 20 worst areas for teenage pregnancy, there are now no dedicated TPCs in Walsall, Tameside and Waltham Forest in east London.

This comes on top of a further 16 posts that had been ended, or rolled into other jobs, in previous years. In addition, England's nine regional TPC posts were cut at the end of March, at the same time as the National Support Team (NST) for teenage pregnancy, which provided free consultancy-style support to those working on the issue locally, was closed down.

Senior figures warn that the combined effect of the cuts will not only halt progress but lead to teenage conception rates rising again. "To have TPCs disposed with is very bad news. You'll see a reduction in bottom-line expenditure next year, but if you have to look after more and more teenage mums in the future you're wasting a lot of money," says Nottingham North MP Graham Allen, the author of a government-commissioned report on early intervention programmes for young children, who also chairs the teenage pregnancy taskforce in the city.

Gill Frances, the former chair of the now defunct Teenage Pregnancy Independent Advisory Group, which monitored the implementation of the 10-year strategy, says the lack of transition planning is "careless and irresponsible".

"Teenage pregnancy hasn't gone away – it's alive and well," Frances, who now does consultancy work, says. "There has been no leadership from the government, absolutely none. This is at their peril, because the [teenage pregnancy] rate will go up. It's very, very disappointing."

Keith Wilson, who was the TPC for Leeds between 1999 and 2003, says he is furious about what is happening. "It fills me with despair – the whole infrastructure has dissolved. So much expertise will be lost by getting rid of TPCs. If you don't have a local champion who's overseeing the work on a regular basis there will be a loss of priority – the focus just goes. If rates start going up, people will find themselves having to start all over again."

A survey of TPCs, seen by SocietyGuardian, found many believed that work on the issue would be hit. The MSc research by Joanna Nichols – herself a former TPC and at the time seconded to the NST – found that a quarter of the 60 respondents, questioned in 2010, thought teenage pregnancy would not be a priority in their area over the following 18 months. Half said they believed it would be a priority, but with reduced delivery, while only a quarter were confident it would retain the same level of importance.

Among the 25% who predicted teenage pregnancy would no longer be a priority, a lack of capacity in a reduced workforce was the biggest concern. Funding cuts from the local authority or PCT were also cited as reasons, as well as the perceived "ending" of the teenage pregnancy strategy.

One TPC told Nichols anonymously: "The new senior managers for health and the local authority seem to have no understanding of the need to continue SRE [sex and relationship education] and young people's access to contraception. Because our [teenage pregnancy] rate has come down then [they think] there is no need to continue, job done. It is tragic."

Nichols also interviewed Alison Hadley, the senior civil servant in the Department for Education who leads work on teenage pregnancy nationally. She said the fact that teenage pregnancy was being proposed among the new public health outcomes, against which the NHS will be judged, showed it was clearly still a priority. But she also raised concerns about the impact of the localism agenda, at the same time as system-wide health reforms are implemented.

"At a time of such rapid change, my concern might be that work will halt and there will be a hiatus ... I could well predict that over the next year or so the [teenage pregnancy] rates will stall or start increasing ... Hopefully, the new structures will deal with the issue and will make further progress, but my concern would be that momentum may be lost before that happens," Hadley told Nichols.

She warned that the health reforms could lead to a watering down of the multi-agency approach needed to reduce rates of conceptions and suggested that the removal of centrally imposed targets in favour of locally decided priorities might see teenage pregnancy demoted in some areas.

"Even if local areas don't see it as a major issue, there will be young people who are at risk and need support," Hadley said. "We know, for example, that 138 out of the 152 local authorities have at least one ward with very high rates of teenage pregnancy. If those young people are not supported, inequalities in the area will increase. That's not acceptable for the young people themselves and, on purely economic terms, it will cost the area more in the long term."

Liverpool is one area that is keeping its TPC, even in the face of an ever-tighter squeeze on funding over the last three years. "We saw it as really key in supporting us to reduce rates and ensure that those who get pregnant are supported to maximise their potential," says Susie Gardner, who leads on public health at the city's PCT, and is a former TPC herself. An evaluation showed that targeted work does have an impact, she says: of 10 "hotspot" wards identified in the city for a particular focus, seven saw reductions in the rate of teenage pregnancy between 2003-05 and 2006-08.

Ultimately, Frances fears that the gaps opening in the system may lead to a step back not just in achievement but even in the argument around the issues.

"We'd got to the point where there was a general consensus that we should be supporting young people to learn about sex and relationships, and support young mothers," she says. "Now we're flopping back. The debate around these issues is becoming a polemic again, and that's a real danger."

A Department for Education spokeswoman says: "We are committed to reducing teenage pregnancy rates – and will be saying more about how we plan to do this in our youth policy statement and the Department of Health's sexual health document later this year."