Infections in Pregnancy

Transmission from mother to child

The transmission of an infection from the mother to the fetus or the newborn, called "vertical transmission", can occur during pregnancy, during the birth or during breastfeeding.

For transplcental infection it means that which is contracted in the period from the moment of conception to the moment of the beginning of labor. It occurs through the blood of the infected mother and the lesions are caused by the direct action of the pathogen (which causes the disease) on the "embryo (first 12 weeks of pregnancy) or on the fetus (from the thirteenth week of life until delivery). The lesions are generally more serious in the case of infection in the first months of gestation, since in this delicate period the "organogenesis, that is, the formation of organs and systems.
For perinatal infection we mean what happens during the passage through the birth canal. It can be caused by the ingestion or inhalation by the newborn during its passage of pathogens present in the birth canal (in the mucous membranes of the cervix or vagina for example) or by the introduction through small lesions on its skin or mucous membranes (which occurs very frequently during childbirth due to trauma) of infected maternal blood.
For postnatal infection we mean that which occurs through breastfeeding or by direct contact of the newborn with the saliva or with the lesions on the skin of the infected mother.
Germs can come by:

Hematogenic (from the bloodstream): as regards Bacteria (Treponema pallidum, Toxoplasma Gondii, Listeria Monocytogenes, Plasmodium) and Viruses (Cytomegalovirus, HIV, Rubella, Parvovirus B19, Varicella Zoster);
Transcutaneous-abdominal: it is rare, and may be due to an "amniocentesis or a chorionic villus sampling;
Ascending: from microorganisms external to the mother (Clamydia, Herpes Simplex Virus, Human Papilloma Virus, HIV, Hepatitis B and C) or internal (beta-haemolytic streptococcus, Mycoplasma Hominis, Ureoplasma Urealiticum, Gardnerella Vaginalis, Mobiluncus, Pepto-Stretococci, Bacteroides, E coli, Klebsiella, Staphylococcus).

Some of these pathogens are grouped under the name of TORCH Complex:

T = toxoplasma;
O = other agents (Varicella, Measles, Hepatitis C and B, Parvovirus B12, Listeria Monocytogenes, Syphilis, Gonorrhea, Chlamydia);
R = rubella;
C = cytomegalovirus;
H = herpes simplex virus.

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Viral infections

Bacterial infections

Parasitic infections

Viral infections

Rubella

Transplacental infection

The risk of infection of the product of conception varies according to the gestation period in which the mother contracted rubella: it is 80% in the first 3 months, and 40% in the second and third trimester of pregnancy. In infections contracted in the very early stages of gestation (period of embryogenesis, that is when the embryo is formed), called rubeolic embryopathy, stillbirth, spontaneous abortion or the birth of a stillbirth are frequent. Only some anomalies are evidenced by ultrasound. If the newborn is alive at birth, he may have severe heart (persistence of Botallo's duct), brain (small brain and mental retardation), hearing (deafness), and eye malformations. In the days following the birth, you may experience purpura (diffuse subcutaneous hemorrhages), an increase in the volume of the liver and spleen, pneumonia, bone lesions. In some cases the lesions are not manifest at birth but present a few years later with reduced hearing (hypoacusis) or mild mental retardation. The diagnosis of maternal infection is often not easy, because it does not always manifest itself with the typical rash, but atypically or without symptoms. With a test called ELISA, in case of infection, early antibodies against the virus (Immunoglobulin M) appear after a very short time and reach a peak in 7-10 days, persisting up to 4 weeks after the appearance of the rash (sometimes even for 2 months). Late antibodies (Immunoglobulins G) appear from the second week after the onset of the rash and persist for life giving protection. As soon as there is suspicion of contagion to the pregnant woman, specific immunoglobulins that have the function of attacking the virus, even if this treatment is not always effective. There are no means to prevent the lesions of the embryo and / or the fetus from rubella; therefore, the vaccination that is carried out in girls before they reach fertile age is very important.

Cytomegalovirus (CMV)

Transplant, perinatal, postnatal infection

Infection affects 0.2-2% of all newborns and, of these, 10-15% will have symptoms. In the mother, the infection often does not cause symptoms and the virus is eliminated for a long time with various body fluids. which represent the most important source of contagion. The incidence of vertical transmission does not depend on the time of gestation, but the fetal sequelae are more severe if the infection is contracted in the first trimester. 10% of infected fetuses will suffer death at birth or severe brain damage with mental retardation, 90% will be asymptomatic and, in 5-15%, will develop damage to the nervous system, especially high-grade deafness, small brain (microcephaly), cerebral calcifications, eye injuries. The infected newborn, even if it does not have malformations, can rapidly undergo severe hepatitis, pneumonia, purpura, jaundice and anemia.
The screening is based on the mother's blood tests for IgM and IgG antibodies (before conception and again in pregnancy at the 18th -20th week and after the 36th week), and on ultrasound, which can show some damage of the fetus.
The prenatal diagnosis is always based on the search for antibodies in the mother's blood, on ultrasound and on the search for the DNA of the virus by means of a test called PCR and carried out on the amniotic fluid (not earlier than 20-21 weeks).
The preparation of a vaccine is currently in the experimental phase.