During pregnancy, the body's natural defences are compromised - the immune system undergoes significant changes to allow a woman's body to tolerate the foetus which would otherwise be considered a foreign object. This means that succumbing to colds, coughs and other complaints is commonplace. But with many medications considered unsafe, working out what you can and cannot take to aid recovery is a minefield. Here we look at the best routes to avoiding and treating illness:

HEADACHES AND MIGRAINES

Risks:

During pregnancy, headaches and migraines have actually been shown to decrease in people who usually suffer from them regularly. A study at the Institute of Nervous Diseases at the University of Rome confirmed the findings of previous researchers when it showed that pregnant migraine sufferers had fewer attacks than before and, as their pregnancies progressed, they experienced fewer and fewer headaches. Around 80 per cent of the people who normally got migraine headaches had none at all during the nine months of carrying their unborn child. However, the headaches returned with their usual frequency after childbirth.

What to do:

Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are not recommended during pregnancy as they have been linked to complications in labour and aspirin can also increase the risk of bleeding in the mother and baby, particularly if taken in the third trimester. For mild to moderate headaches, only paracetamol is safe in pregnancy and can be taken to treat both headaches and mild fever. "Each dose of paracetamol (one to two 500mg tablets) lasts about four hours, and a maximum of 4g (eight 500mg tablets) can be taken in 24 hours," says GP Dr Morag Martindale.

A gentle head massage can sometimes help. For migraine sufferers, the advice from the UK's Migraine Trust is "to take as few drugs as you can and at the lowest effective dose." Some migraine tablets contain ergotamine which has been shown in trials to stimulate the muscles of the uterus, raising the risk of a miscarriage. The Trust also says that the use of triptan drugs should be avoided and, while paracetamol is safest, your doctor will be able to prescribe a migraine medication suitable for use in the second and third trimesters of your pregnancy.

Read more: 'Pregnancy Diet: The 12 foods to eat when you're expecting'

COUGHS AND COLDS

Risks:

With lower immunity during pregnancy, many women find they suffer a constant stream of niggling coughs and colds. Remedies often contain a combination of several ingredients, including painkillers, antihistamines and decongestants, many of which it is recommended to avoid during pregnancy. Cough medicines containing iodine as an expectorant should be avoided, as the iodine might impair the functioning of a baby's thyroid gland.

What to do:

Drinking lots of water or warm drinks can help to relieve a chesty and inhaling steam can help to loosen mucus. "Although there is no confirmed evidence that vitamin C reduces the duration or intensity of a cold, there is no harm in taking the recommended daily allowance of 40mg if you think it helps," says dietician Louise Sutton. "However, more than this is inadvisable as it can cause diarrhoea and tummy ache." Some soothing cough mixtures are safe to take, but check with your pharmacist. Honey is also a well-known cough suppressant and throat soother, and its antimicrobial properties mean it can also boost your immune system – try mixing some in warm water with lemon juice and fresh ginger for a stimulating and soothing drink.

Read more: 'Caffeine in pregnancy: Why even decaf coffee and tea could harm your baby'

FLU

Risks:

Because of their compromised immune systems, pregnant women are statistically more likely to catch the influenza virus than other women, and the later they catch it in their pregnancy, the worse it is. Studies show that women who get flu during pregnancy are not only at greater risk of dying in childbirth, but that their babies are more likely to have brain damage that causes emotional and development problems, including ADHD.

One study suggested that flu in pregnancy doubles the risk of childhood leukemia because the virus triggers changes in a baby's immune system that can increase the likelihood of the blood cancer later in their life. Fever - a symptom of flu - in pregnancy has also been linked to behavioural and psychological disorders in young children by some researchers. A study at Rider University in New Jersey showed that women who had a fever during the second trimester of their pregnancies gave birth to babies who were more likely to become stressed around new situations or strange adults when they were six months old. At five, the same children were not able to play contentedly for as long as their peers and at 12 they seemed to more difficulty focusing on academic tasks.

What to do:

In a study published in the New England Journal of Medicine, Professor Mark Steinhoff, from Johns Hopkins University Bloomberg School of Public Health in Baltimore, Maryland randomly assigned 340 women in Bangladesh to have the flu vaccine while pregnant. He found fewer cases of flu in the newborn babies whose mothers had the flu jab and one third fewer cases in the mothers. Unlike vaccines for some other illnesses, the flu vaccination is considered safe to take during pregnancy and is already routinely given to pregnant women in the US and Canada. It is thought that the vaccine may also protect the baby against catching the virus in the first months of life. Some medical experts only recommend flu jabs for at-risk groups such as those with diabetes, chronic respiratory diseases like asthma and chronic heart disease.

If you do get flu, doctors recommend you drink plenty of water, take paracetamol to treat a high temperature, headache and muscle pain, but only take over-the-counter medications after consulting a pharmacist or doctor. Generally, aspirin and non-steroidal anti-inflammatories (such as ibuprofen) should be avoided, particularly in the third trimester.

Read more: 'Flu in Dubai: Why pregnant women should get vaccinated against it'

TONSILITIS AND BACTERIAL INFECTIONS

Risks:

Although bacterial infections, like tonsillitis, are generally treatable with antibiotics, doctors are now being warned not to prescribe the medication to women at risk of premature labour as it may increase the chance of their babies getting cerebral palsy, following a study designed to look into their effect on premature births. Dr Sara Kenyon of Leicester University who led the study that was published in the Lancet, found that erythromycin and another antibiotic called co-amoxiclav, appeared to have harmful effects for some children born to mothers in premature labour whose waters had not broken. When the children were re-assessed at seven, those born to mothers who had taken antibiotics were likely to have cerebral palsy.

What to do:

Despite this study, the Royal College of Obstetricians and Gynaecologists insists most pregnant women showing signs of infection can be treated promptly and safely with antibiotics. Dr Kenyon says, "Where there is an obvious infection, antibiotics should be prescribed because they could be lifesaving for mother and baby."

With tonsillitis, drugs containing paracetamol can also be taken to bring down temperature, warm drinks, soft food and throat lozenges or boiled sweets can help to ease swallowing.

Read more: 'The 5 kinds of bacteria pregnant women should look out for'

CONSTIPATION

Risks:

About 40 per cent of women experience constipation during pregnancy, mostly during the early stages. It is thought be a result of raised levels of the female hormone progesterone acting as a relaxant to the intestinal muscles combined with the pressure of the expanding uterus on the intestines. Relaxation of the intestinal muscle causes food and waste to move slower through your system. Iron tablets prescribed for anaemia - common during pregnancy - may also contribute to constipation.

What to do:

"Always try drinking more fluids and eating more high fibre foods, including dried and fresh fruit and wholegrain cereals, before resorting to other measures," says Sutton.

"If that doesn't work, there are lots of laxatives that are safe for pregnant women - including the bulking agents like lactulose and macrogols - which can help soften your bowel movements and reduce constipation. You should always remember to ask your pharmacist or doctor before taking laxatives, however, as others are not suitable."

Read more:

'Bleeding gums in pregnancy: How to fix it'

'6 beauty product swaps you should make as soon as you find out you're pregnant'

'Your First Trimester in the UAE: Your essential pregnancy guide for weeks 1 to 6'

This article first appeared in Aquarius magazine