Infections in Pregnancy

Transmission from mother to child

The transmission of an infection from the mother to the fetus or to the newborn, called "vertical transmission", can occur during pregnancy, coinciding with delivery or during lactation.

For transplicy infection is meant 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 the birth) . The lesions are generally more severe in the case of infection in the first months of gestation, since in this delicate period organogenesis takes place, that is the formation of organs and apparatuses.

Perinatal infection means that which occurs during passage through the birth canal. It can be caused by 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 on its mucous membranes (which during childbirth occurs very frequently due to trauma) of infected maternal blood.

Postnatal infection means that which occurs through breastfeeding or direct contact of the newborn with saliva or lesions on the skin of the infected mother.

Germs can come via:

1. Hematogenous (from the bloodstream): regarding Bacteria (Treponema pallidum, Toxoplasma Gondii, Listeria Monocytogenes, Plasmodium) and Virus (Cytomegalovirus, HIV, Rubella, Parvovirus B19, Varicella Zoster);
2. Transcutaneous-abdominal : it is rare, and can be due to an amniocentesis or to a chorionic villus sampling;
3. Ascendant : from microorganisms external to the mother (Clamydia, Herpes Simplex Virus, Human Papilloma Virus, HIV, Hepatitis B and C) or internal (beta-hemolytic 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

Rubella Cytomegalovirus (CMV) Parvovirus B19HIV - VaricellaHerpes Simplex (HSV) Other viruses

Bacterial infections

SyphilisListeria MonocytogenesTuberculosisChlamydia TrachomatisStreptococcus of BGonorrea group

Parasitic infections

ToxoplasmosiMalaria

Viral infections

Rubella

Transplacental infection

The risk of infection of the product of conception varies according to the period of gestation in which the mother has contracted rubella: it is 80% in the first 3 months, and 40% in the second and third trimesters. In infections contracted in the earliest stages of gestation (embryogenesis period, ie when the embryo is formed), called rubeolic embryopathy, death in the uterus, spontaneous abortion or the birth of a dead fetus are frequent. Only some anomalies can be detected with ultrasound. If the newborn is alive at birth, it may have severe cardiac malformations (persistence of the Botallo duct), cerebral malformations (small brain and mental retardation), hearing (deafness), and the eye. In the days following birth, it may develop purpura (widespread subcutaneous haemorrhage), increased volume of liver and spleen, pneumonia, bone lesions. In some cases the lesions are not manifested at birth but occur a few years later with reduced hearing (hypoacusis) or mild mental retardation. The diagnosis of maternal infection is often not simple, because it does not always manifest itself with the typical rash, but in an atypical or symptom-free manner. With a test called ELISA, in case of infection, the early antibodies against the virus (Immunoglobulin M) appear very quickly and reach a peak in 7-10 days, persisting up to 4 weeks after the appearance of the exanthem (sometimes even for 2 months). Late antibodies (Immunoglobulin G) appear from the second week after the appearance of the exanthe and persist throughout life giving protection. As soon as there is a suspicion of the contagion of the pregnant woman, the specific Immunoglobulins that have the function of attacking the virus will be given to her, even if this treatment is not always effective. There are no means to prevent injuries to the embryo and / or the rubella fetus; therefore, it is very important the vaccination that is carried out in girls before they reach fertile age.

Cytomegalovirus (CMV)

Transplental, perinatal, postnatal infection

The infection affects 0.2-2% of all newborns and, of these, 10-15% will have symptoms. In the mother the infection often gives no symptoms and the virus is eliminated for a long time with various organic liquids, which represent the most important source of infection. The incidence of vertical transmission does not depend on the age of gestation, but the fetal sequelae are more serious if the infection is contracted in the first trimester. 10% of infected fetuses will die at the time of 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 deafness, small brain (microcephaly), cerebral calcifications, lesions of the eye. The infected newborn, even if it does not present malformations, can rapidly undergo severe hepatitis, pneumonia, purpura, jaundice and anemia.

The screening is based on the mother's blood tests in search of IgM and IgG antibodies (before conception and again in pregnancy at the 18th-20th week and after the 36th week), and on ultrasound, which may show some damage of the fetus.

Prenatal diagnosis is always based on the detection of antibodies in the mother's blood, on ultrasound and on the search for the DNA of the virus by an examination called PCR and performed on the amniotic fluid (not before 20-21 weeks).

The preparation of a vaccine is currently in the experimental phase.