You’ve taken the test and...you’re pregnant! Nine months of joyous blooming lie ahead. Or maybe not. For a start, at 40 weeks, pregnancy is actually closer to 10 months than nine. And although it is emphatically not an illness but a perfectly natural state, it can be tough when coupled with a demanding job like teaching.

More than a third of the teaching force are women of childbearing age, and that’s not counting the part-timers who are likely to have had a first child and may be considering a second - so there are a lot of pregnant teachers British classrooms.

Both for the teachers and their schools, it is vital that the mothers-to-be stay healthy and at work. Pregnant office workers can spend much of the day sitting and can often organise their workload to accommodate morning sickness or exhaustion. But the expectant teacher’s working hours will be spent on her feet and pretty much as timetabled.

Many will therefore find themselves trying to appear perfectly normal in front of their colleagues, as well as the eagle eyes of at least 30 pupils - when they feel absolutely dreadful.

Health and safety regulations demand that any pregnant worker’s job should be assessed for potential risks as soon as she notifies her employer of her condition. According to Carol Bannister, occupational health adviser for the Royal College of Nursing, this should be done by “a competent person” - usually not a headteacher. Most local authorities will have such a person in the shape of an occupational health adviser.

Two infections, rubella and cytomegalovirus, can pose problems for pregnant women in schools. All women teachers should ensure they have been immunised against rubella, but pregnant teachers can stay away from work on full pay on a doctor’s advice during an outbreak - providing she does not unreasonably refuse to work elsewhere if her local authority requests this.

Cytomegalovirus is a common infection which can cause damage to unborn babies if left un-treated. Symptoms are vague and can feel like little more than a mild dose of ‘flu. Advice from the National Union of Teachers is to observe good personal and general hygiene procedures, such as regular hand-washing.

Otherwise, says Ms Bannister, risks tend to apply to particular teaching jobs. Teachers who spend a lot of time sitting at computers may need an ergonomic chair and more frequent breaks. Those in schools with some history of violence may need to consider moving from particular classes or situations.

There might also be complications in special schools if, for example, there are pupils who are prone to biting, as they may carry hepatitis.

Some risks vary according to the stage of pregnancy: for instance, chemistry teachers may be at risk from certain chemicals during the first few months.

Most teachers are likely to experience no more than the minor problems of a normal pregnancy. The most common are: morning sickness (which strikes at any time of the day, generally for the first three months), extreme tiredness (usually in the first and final three months) and backache.

Most women cope in commonsense ways, but the demands of teaching can sometimes make things worse. You may have to make frequent trips to the loo in the early weeks, but this can be incredibly difficult when you can’t leave your class. “I used to collar the head or colleagues who were passing and beg them to look after my class for five minutes,” recalls one pregnant teacher.

Vicki Allanach, midwifery adviser for the Royal College of Nursing, says:

“People don’t want to be seen as ill when they are pregnant, but they should look at their workload and see if some simple thing they could do would just make it easier.”

Comfortable clothes - shoes, particularly - are a must. Support tights could also be useful. Vicki Allanach says expectant mothers should also try even harder to take the breaks to which they are entitled, and make sure they sit down and rest during those times.

She also emphasises the importance of getting enough rest and exercise outside working hours - and discussing any problems with your community midwife.

Cathy Humphris is expecting her second child next month and worked as a Year 3 teacher at Patcham Junior School in Brighton until Easter. She found that she pushed herself to do her job as normal but was often helped out by colleagues offering to take over tasks such as playground duty if she looked tired.

Parents were also helpful. “One lovely mother caught me putting up a display with one foot on the sink the first time I was pregnant. She told me to get down and then spent the rest of the afternoon putting it up herself.”

Even though she shared her job with another teacher, she often found herself experiencing “total body shut-down” by the end of the school day. “Morning sickness was dreadful. If I could have worked flexitime and waltzed in at ten o’clock it would have been great. The difficulty is if the first lesson of the day is something high-impact like literacy hour, and you feel grim.”

To avoid standing up all day, Mrs Humphris commandeered a tall, old-fashioned science stool to use at the front of the class; she also had help from colleagues or children for gym lessons which entailed moving heavy equipment around.

PE lessons brought other dangers - during her first pregnancy a child accidentally hit her in the stomach with a rounders ball. The blow was so hard that she was winded.

The secret to successful pregnancy is to find ways to turn it to your advantage. Warned to save her back by never bending down to children’s level, Mrs Humprhis has been doing a lot of squatting over the past few months. “It’s supposed to be excellent practice for delivery,” she says.

And literacy hour has also proved to have unexpected benefits. “Every day, when I was standing up with the overhead projector I would be doing my pelvic floor exercises. Nobody would know, but I made sure I did them regularly.”

The National Union of Teachers and the Association of Teachers and Lecturers publish leaflets on maternity benefits and rights of pregnant women

How to get through a nine-month term

* Morning sickness? Try peppermint or ginger in various forms, such as herb teas and dry biscuits. Eat little and often. Carry snacks such as dried fruit to get over eating emergencies.

* Tired? Rest whenever possible. Don’t be a martyr and work through breaks. Try to vary your teaching style and perhaps sit more. Accept offers of help. Pace marking and preparation by trying to do a sensible amount every night rather than burning the midnight oil twice a week.

* Bad back? This can be a particular problem in pregnancy as your ligaments soften for birth and your bump grows heavier. Ensure your shoes are comfortable and your posture good. Bend at the knees, not the back. Avoid heavy lifting. Ask your midwife for exercises which can help. Yoga and swimming can be beneficial.

* Take sensible amounts of exercise daily: walking and swimming are great. Ensure you do pelvic floor exercises.

* Take time to relax properly but be careful about slumping in soft chairs, as this can exacerbate back problems.

* Some swear by aromatherapy, but take professional advice - some essential oils are unsafe during pregnancy.

* Be careful about hygiene in school. There are a lot of bugs about, and pregnant women are particularly susceptible to them.