Vertical disease transmission
Vertical disease transmission refers to the transfer of pathogens from one generation to the next, typically from a parent to their offspring during conception, pregnancy, childbirth, or shortly after birth. This can occur through various means, such as in sperm, across the placenta, or through exposure to bodily fluids or breastfeeding. Notable infections transmitted in this manner include human immunodeficiency virus (HIV), hepatitis, herpes, and syphilis, often first acquired through horizontal transmission among individuals of the same generation. Pregnant women may not always show symptoms, yet these infections can lead to severe complications for the fetus, including developmental issues or even death. Routine screening for these diseases is conducted for women who are pregnant or planning to conceive, with treatment options that may involve medication for mothers and newborns, adjustments in delivery methods, and vaccination for newborns to prevent future transmission. Identifying and mitigating vertical transmission is crucial for implementing effective preventive measures, although complete prevention of many infections remains challenging. Ongoing research seeks to better understand these transmission dynamics and develop potential treatments or vaccines.
Vertical disease transmission
- ALSO KNOWN AS: Fetomaternal transmission, maternal-fetal transmission, mother-to-child transmission, perinatal transmission
Definition
Vertical disease transmission is the passing of a disease-causing agent (pathogen) from one generation to another, as when a parent transmits a pathogen to potential offspring at conception, during the perinatal period (pregnancy), at labor and delivery, or shortly after birth. The pathogen may be transferred either in sperm, by crossing the placenta, by fetal or newborn exposure to secretions or blood, or through breast-feeding.
Disease Types
Many of the vertically transmitted (VT) infections are first acquired by horizontal disease transmission, meaning from persons within the same generation. For instance, sexually transmitted diseases are passed between partners and then may be vertically transmitted to a fetus. Common examples of VT diseases are human immunodeficiency virus (HIV) infection, hepatitis, herpes, and syphilis. Other infections are contracted by contact with young children or animals and their feces and then vertically transmitted. These infections include cytomegalovirus, toxoplasmosis, and chickenpox. Pregnant women may be asymptomatic, but affected fetuses can have severe disease presentation after birth depending on the timing of exposure. Infections can lead to multiple medical and developmental concerns or to fetal or neonatal death.
Perinatal Testing and Treatment
Women (both pregnant and those planning to become pregnant) are screened on routine blood work for many of the diseases that show VT. Treatments, although specifically tailored to the individual disease, include maternal or neonatal medication (or both), changing delivery route from a vaginal delivery to a cesarean section to avoid maternal-fetal contact in the birth canal, and avoiding breastfeeding. Vaccines for certain diseases, such as hepatitis B, are administered in the newborn period to prevent disease development and VT to future generations.
Impact
It is important to identify vertical disease transmission to apply appropriate preventive measures during pregnancy and labor and delivery. There is no fully effective way to avoid many perinatal infections. However, some changes in obstetrical and pediatric practice have proven effective. For example, when both maternal and neonatal treatment is administered for HIV infection, the VT rate decreases from approximately 25 to 2 percent or less. Ongoing research on animal models aims to identify the predisposing factors for disease transmission and identify possible future treatments, such as medications or vaccines.
Bibliography
‗‗‗‗‗‗‗. “Prenatal and Perinatal Human Immunodeficiency Virus Testing: Expanded Recommendations.” Obstetrics and Gynecology 112 (2008): 739-742.
Khare, Manjiri. “Infectious Disease in Pregnancy.” Current Obstetrics and Gynaecology 15 (2005): 149-156.
Moore, Sarah. "What Is Vertical Transmission?" News Medical, 15 May 2021, www.news-medical.net/health/What-is-Vertical-Transmission.aspx. Accessed 4 Feb. 2025.
Taverna, Paola, et al. “CMV Infection in Pregnancy: Prevention of Vertical Transmission by Means of Specific Immunoglobulin Therapy (CMV-IgG).” Early Human Development 85 (2009): S98-S99.