Since the 19th century, scientists have understood that there is a link between pregnancy and an increased susceptibly to infection. Up until the early 20th century, this link between pregnancy and increased severity of infectious disease caused doctors to recommend therapeutic abortion to pregnant women with tuberculosis to reduce the effect of the disease on the mother.
Pregnant Woman holding Face Mask. Image Credit: PH888/Shutterstock.com
While effective preventative and therapeutic interventions have since been developed to treat tuberculosis, the link between pregnancy and infectious disease remains and is still an issue with other illnesses. Studies have shown that when pregnant, a woman’s adaptive immune responses become less strong, which is theorized as being the root of the reduced viral clearance observed in pregnant women.
Additionally, evidence also demonstrates that the body’s innate immune response is increased during pregnancy, which may have developed to respond to the reduced adaptive immune response to protect the pregnant woman and her fetus from the consequences of infection.
Infectious disease severity augmented during pregnancy
To date, numerous studies have been conducted that provide some evidence to pregnant women experiencing an elevated severity of symptoms to specific infectious diseases. Evidence shows that influenza, hepatitis E, herpes simplex virus (HSV), and malaria may present more severe symptoms in pregnant women.
Additionally, evidence also suggests that pregnant women may also be at risk of increased severity of symptoms when infected with measles or smallpox. Data also suggests that symptom severity may increase along with pregnancy, so that women at the final stages of their pregnancy may be more severely affected than those at the beginning stages.
Some evidence suggests pregnant women are more susceptible to contracting infections
Further recent studies have hinted that pregnant women may also be more susceptible to contracting infectious diseases as well as suffering from more severe symptoms. Data shows that pregnant women may be more susceptible to contracting HIV, listeriosis, and malaria, although more data is needed to confirm this assumption.
Infectious diseases that may affect the fetus
Becoming infected with chickenpox during pregnancy can be dangerous for both mother and baby. Women who are pregnant are advised to contact their GP as soon as they see the symptoms of chickenpox or have come into contact with someone who has it. In many countries, adults have immunity to chickenpox, however, blood tests can confirm if a pregnant woman is immune or not.
The cytomegalovirus (CMV) is a virus that is part of the herpes family. It is responsible for causing cold sores as well as chickenpox. While CMV infections are common in children, the virus can be dangerous for a woman to contract during pregnancy and can affect the fetus. It is recognized that babies born of women who were infected with CMV during pregnancy may suffer from hearing loss, blindness or visual impairment, epilepsy, or learning difficulties.
In cases where the mother has not been infected before and experiences her first CMV infection during pregnancy, there is an elevated risk for the baby. Healthcare professionals advise that many simple preventative measures can be taken to prevent passing CMV infections to young babies. These strategies involve regular hand washing, the avoidance of kissing children on the face, and not sharing cutlery or cups with children.
Group B streptococcus (GBS) rarely presents a danger to the baby. However, in a very small number of cases, the infection can pass from the mother to the baby and can cause serious illness. Women who have had a group B step urinary tract infection whilst pregnant should be offered antibiotics during labor to prevent the baby from contracting the virus during birth. Certain situations can also make it more likely for the child to contract the virus from the mother, such as during premature birth, if the mother has had a fever during pregnancy or if her waters break early.
While most adults who become infected with hepatitis B often fully recover within months, babies who contract the virus during pregnancy are prone to chronic infections, with 90% of babies born with the infection going on to develop chronic hepatitis B. Pregnant mothers should be offered blood tests for hepatitis B infection so that at-risk babies can be given a vaccination at birth to avoid chronic infection and liver disease.
Similarly, hepatitis C can be passed on from mother to baby, and blood tests should be done during pregnancy to assess a child’s risk. While transmission of the virus from mother to baby is less likely than with hepatitis B, there are currently no methods to prevent this transmission.
Herpes is another virus that can pass from mother to baby, however, it is quite preventable. If a woman contracts her first herpes infection towards the end of her pregnancy, a cesarian section will likely be recommended as a means of preventing passing the infection onto the child.
Finally, while HIV infection is unlikely to have a significant impact on a pregnant mother if she has no symptoms of the infection, there is a high risk of her passing the infection onto her baby. Fortunately, treatment during pregnancy can reduce this risk from 1 in 4 to less than 1 in 100.
Overall, it is important that pregnant women have access to up-to-date information about the impact of infections on their own health and their baby’s health. While many infections can have a negative impact on both mother and child, there are many preventative and therapeutic methods to protect the health of the parent and baby.
References:
- Infections in pregnancy that may affect your baby. NHS. Available at: https://www.nhs.uk/pregnancy/keeping-well/infections-that-may-affect-your-baby/
- Sappenfield, E., Jamieson, D. and Kourtis, A., 2013. Pregnancy and Susceptibility to Infectious Diseases. Infectious Diseases in Obstetrics and Gynecology, 2013, pp.1-8. https://www.hindawi.com/journals/idog/2013/752852/
- Starke, J., 1997. Tuberculosis. Clinics in Perinatology, 24(1), pp.107-127. https://www.sciencedirect.com/science/article/abs/pii/S0095510818301878?via%3Dihub
- 10 Tips for Preventing Infections Before and During Pregnancy. CDC. Available at: https://www.cdc.gov/pregnancy/infections.html
Further Reading
A deeper look at COVID-19 transmission and fetal health