Influenza, Swine Flu (H1N1) and Common Cold during Pregnancy

Reduced immunity during pregnancy may be the reason why expectant mothers are more prone to catch colds or suffer from influenza (flu) and other illnesses. The common cold and influenza are viral infections of the respiratory system, with very similar symptoms, yet there are other important differences between these types of inections.

Causes of Influenza, Swine Flu and Common Cold

A cold is  very common, hence the term “common cold”. It is an extremely contagious infection of the nose and throat, which may be caused by any of a large number of viruses. Overall the cold is a harmless condition which usually resolves on its own without any long-lasting effects.

Influenza is a highly contagious acute viral infection caused by the influenza virus. It usually affects the nose, throat, bronchial tubes, and occasionally the lungs. It can complicate to more serious conditions.

There are 3 types of influenza virus – A, B and C.  Of these, type A and type B influenza viruses produce more serious illnesses and are often involved in causing epidemics.

The type A virus frequently mutates to different strains, thus making it difficult for humans to develop permanent resistance towards it. In 2009, a new strain of influenza virus spread rapidly across, causing the H1N1 influenza or the swine flu pandemic. Type C influenza virus causes very mild symptoms and does not produce epidemics.

Spread of Influenza and Common Cold

Common cold and influenza are spread in similar ways. Close contact with an infected person helps to spread the virus.

Tiny droplets carrying the virus are expelled from the mouth or nose when an infected person coughs or sneezes. These may remain suspended in the air or get deposited on nearby objects and surfaces (fomite). Others in the vicinity may inhale the virus or it is spread by touching the contaminated surfaces and putting the hand to the mouth, nose or eyes. The infection can even be spread by shaking hands or by using any contaminated object.

On entering the body through the mouth, nose or eyes, the virus travels down the respiratory system and may even reach the lungs in case of influenza. Rapid multiplication of the virus within the respiratory system gives rise to the initial symptoms of cold, cough and sore throat. As the illness progresses, other symptoms such as a fever, headache and body ache develop.

The transmission of swine flu (H1N1) is similar but is discussed further under Swine Flu Spread. Refer to What is Incubation Period? for the incubation period of influenza and swine flu.

Symptoms of Influenza and Common Cold

Symptoms of a common cold generally develops gradually over one to three days and then subsides in about a week’s time. The symptoms include :

• Runny nose
• Nasal congestion
• Sneezing
• Cough
• Sore throat
• Decreased sense of taste and smell
• Slight headache
• Mild fever

The symptoms of influenza may be similar to those of the common cold but usually has a more acute onset (develops suddenly) and may be more severe in intensity. In addition to the above symptoms, a person may also suffer from :

• High fever – 101 F (38 C) or more.
• Chills
• Sweating
• Headache
• Body ache
• Muscle pains
• Weakness
• Loss of appetite

Effects of Influenza and Common Cold during Pregnancy

• Except for the associated discomfort, there is usually no other problem that a pregnant woman or the unborn baby is likely to face when suffering from common cold.
• Although most cases of influenza in a pregnant woman will be mild to moderate in severity, the risk of a more serious illness should be kept in mind.
• Immunological alterations in pregnancy may be responsible for greater susceptibility to as well as increased severity of illness.
• Pregnant women may be at increased risk for influenza complications, mainly as a result of various physiological changes that occur during pregnancy, especially related to the cardiovascular and respiratory systems.
• A higher number of deaths has been reported due to influenza complications in pregnant women than in the general population.
• Delay in treatment with antiviral medicines has been suggested as the cause of death in most pregnant women who contracted  the H1N1 influenza (swine flu).
• Pregnant women with underlying medical conditions such as diabetes, asthma, COPD, and heart problems may be more at risk of developing complications.
• There is much controversy regarding the likelihood of increased risk of spontaneous abortion (miscarriage), preterm labor, fetal death, or congenital abnormalities in a pregnant woman who contracts influenza. Certain studies suggest a possibility of increased risk of these adverse outcomes, especially when influenza is complicated with pneumonia.
• Prolonged high fever accompanying influenza in pregnancy may have harmful effects on the fetus, especially in the first trimester. The risk for adverse effects, especially neural tube defects in the baby, may be decreased with a shorter duration of fever, use of antipyretics (anti-fever drugs), and use of folic acid in early pregnancy.

Complications of Influenza and Common Cold

There is usually a good recovery from common cold without any complications. Most pregnant women with influenza will recover without further problem, but some may develop complications such as :

• Pneumonia
• Bronchitis
• Ear infections (otitis)
• Sinus infections (sinusitis)
• Death, especially when influenza is complicated with pneumonia.