Flu or influenza is a contagious viral infection caused by certain RNA viruses belonging to the Orthomyxoviridae family (influenzavirus A, B and C). Flu during pregnancy can be harmful for the fetus, especially in the later stages, unless treated properly .
Pregnancy alters your hormone levels and immune system functioning, so your body does not refuse the changes occurring in your body. Otherwise, your immune system would try to get rid of the fetus, which is a foreign element to your body . On the other hand, you become much more susceptible to infections and diseases as your immune system is no longer able to fight them off as well as before you got pregnant . Due to this reason, you are more likely to get affected by flu while pregnant.
The influenza virus has an incubation period of 3-5 days, meaning the virus takes 3-5 days to multiply in your body and cause visible symptoms .
The mother may develop life threatening complications such as:
Risks to the baby mainly include those associated with preterm delivery, such as low birth weight. Other potential risks include stillbirth and death of the baby within a week after birth , while recent studies show that flu in the mother also increases the chances of the baby developing conditions like autism  and bipolar disorder .
Getting the vaccination before the influenza season (early October to May)  is the only way of preventing the disease in pregnant women . According to the NHS, the flu shot is safe for all women, whether in their first, second or third trimesters . It can be given along with the vaccine for whopping cough without any adverse reactions . It is recommended to talk to your doctor regarding the flu jab and its potential effects.
This is one of the most common myths about the flu immunization process. However, there is no risk of getting sick from the vaccine as it only contains dead viruses as its principal ingredient . The nasal spray shot known as live, attenuated influenza vaccine (LAIV) contains weakened (attenuated)  viruses; but, it is strictly not recommended for pregnant women .
Most women do not experience any adverse reactions while some may experience the following mild flu-like symptoms within a couple of days after getting the vaccine:
Some women may experience faintness and certain allergic reactions. However, the potential benefits of getting the flu vaccine surpass the possibility of adverse effects. People allergic to chicken eggs should avoid the regular vaccine as eggs are used for growing the inactivated viruses present in it . If you have an allergy, consult your doctor about getting the egg-free vaccine .
The cost for a single shot ranges between $5 and $10 .
The condition is usually diagnosed based on the symptoms. But in some cases, your doctor may run a few influenza tests to confirm the diagnosis. It is crucial to start the treatment at an early stage of the infection to avoid hospitalization and the use of potentially harmful antiviral drugs.
Consult your doctor about taking over-the-counter medications like paracetamol (Tylenol) as they are generally considered safe for pregnant women . He or she can also prescribe some other safe antiviral medicine if necessary. It is vital to lower your temperature to prevent immediate complications. However, non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are not considered safe during this time .
Usually, the symptoms of influenza remain for a few days to a week . However, according to some studies viral diseases like colds and flu tend to last 2-3 times longer in pregnancy .
You are likely to remain contagious as long as the symptoms persist . Some women may continue to shed the virus even after the treatment due to the weakened immune system.
Call your doctor immediately in case of any of the following symptoms, even if you are on flu medication:
The ICD-9 code used for indicating flu is 487 , while its ICD-10 codes are J10 and J11 .