Every pregnant woman should know the risks and harmful agents with which she might have contact, voluntary or involuntary, within her environment and advise herself regarding the possibility of risk for her and / or her baby. The work environment must be specially evaluated and local risks considered: for example, if you work in a gasoline pump you are in contact with hydrocarbons and lead, the preschool assistants could have frequent contact with infectious-contagious viral diseases such as Rubella and same could be said of adolescent teachers in the case of Infectious Mononucleosis; Dental Assistants are in contact with Mercury and those working in Radiology are exposed to Ionizing Radiation; a secretary could suffer thrombosis in the legs due to the sitting position for hours and a cook could suffer from varicose veins and thrombosis due to standing for a long time. As you see, almost all human activities can impose risks, to a greater or lesser degree, on a pregnant woman.

Exposure to Biological Agents

I Natural Viruses

Viruses are inert organisms that need another living being to replicate and spread from one host to another, the best known are the respiratory viruses that are infected with respiratory secretions, some of them are frankly respiratory since they produce infections exclusively in the pathways but there are others that once acquired by this route will have more influence on organs such as the skin, the lymphatic system, hematology, liver, etc. Viruses are everywhere and can be transmitted by sick people or healthy carriers, hence the difficulty in preventing the diseases that some of them produce. The best way to combat them is to avoid entering the body and this is only achieved through vaccinations. Let’s see some frequent viral diseases:

Common Catarrh: also called Influenza in our latitudes, is a universal viral disease that can affect anyone and anywhere in the world, there are hundreds of viruses capable of producing a cold but usually do not cause maternal complications and fortunately never cause fetal problems of the malformation type congenital There is little that can be done to prevent a cold, I can only suggest that you stay away from those people with “flu” with obvious symptoms and avoid places with large crowds (this is valid to prevent many infections).

Rubella: This is the viral disease most feared by obstetricians and their pregnant patients, as it can be catastrophic for the baby. The rubella virus (infection usually asymptomatic or with general symptoms, respiratory and skin discrete) is capable of generating great havoc in a developing baby, especially before the 10th week of pregnancy. It is acquired after the entry of the virus through the airways of the host to have contact with infected people and their respiratory secretions (cough), in the mother will not cause major problems or may even go unnoticed but in the baby will almost certainly produce effects devastating over multiple organs.

In a good health system all girls before age 15 should be vaccinated against rubella and in the general population most women of reproductive age or have been vaccinated or have suffered the disease naturally, this is the reason for which many cases of Congenital Rubella are not seen.

How to prevent Rubella : (1) if you have never been vaccinated, DO IT! (if you are not pregnant and you know you will not be in the next 3 months after the vaccination), (2) if you have doubts about your vaccination or having suffered the disease, ask for an order to perform a serology of Rubella in blood and if the results suggest that Rubella has never given you and you are pregnant stay away from children with fever and skin rashes. Preschool teachers have the greatest risk of contagion since this is the population vaccinated with live viruses and who most frequently suffers from this disease.

Varicella: also known as Chicken Pox, in some Latin countries, is a disease caused by a virus (Varicella-Zoster) of high infectiousness, very symptomatic and easy to recognize due to high fever, general malaise and the typical herpetic skin vesicular lesions. The disease is so remarkable that the most economical way to prevent it is to avoid being near a child or adolescent (or even adult) with the symptoms and signs typical of the disease if we have not suffered, we are not sure or simply have doubts. If we want to prevent it in an efficient way we must request the vaccine (Varivax)

Fortunately, the Varicella virus has very little affinity for the fetus and reports of injury are limited and not very aggressive. If Varicella occurs days before delivery, be very careful because this disease in the newborn can be very severe, especially at the pulmonary level.

Infectious mononucleosis: there are two viruses that produce it, the Cytomegalovirus (CMV) and the Ebstein-Barr Virus (EBV), it is also known as the “Kiss Disease” since it is common to observe it among adolescents when they start their relationships and intimate contact with fluid exchange (kisses). It manifests as a cold, discomfort in the throat and swollen glands but can go unnoticed in many cases. Although its course is usually benign in the host, the story changes when the affected person is a pregnant woman since the virus has an affinity for the baby’s tissues and can cause irreparable damage to many of them. Since intimate contact is the main form of contagion, good personal hygiene is recommended, avoiding intimate contact with unknown persons and frequent hand washing, especially when children or adolescents are in charge of sick people.

II Attenuated viruses

When we speak of attenuated viruses, we refer to modified “laboratory” viruses for the manufacture of vaccines. These viruses, which are the same that produce their particular diseases, have been “modified” to produce a very discreet infection, with little or no disease but with an intense immune response that prevents a natural infection by the same “natural” agent not toned down There is an increasing number of live attenuated virus forming part of the vaccines of frequent use, among them we can mention the vaccines against: Rubella, Varicella, Measles, Yellow Fever, Polio.

In general, live virus vaccines are contraindicated during pregnancy since some of them have enough residual virulence to affect a developing fetus. If you were vaccinated with any of these vaccines you should wait 3 months before getting pregnant; if there was an accidental vaccination without knowing that you were pregnant you should go to your obstetrician to tell you if there is any risk (not all affect the baby). Visit the inadvertent vaccination article during pregnancy

III Bacteria

Bacteria also share the ubiquity of viruses, they are everywhere (even in us), but they have a different behavior, less generalized and less aggressive from a fetal point of view. Although a bacterial infection could compromise the life of the mother or her baby, the mechanism is different and generally more evident in terms of its origin, gateway to the body and clinical manifestations. In addition, unlike what happens with viruses, for bacterial infections there are excellent antibiotics that can eliminate most of the infections they produce and once cured do not leave sequelae in the fetus or the mother. The prevention of bacterial infections is basically based on personal hygiene and the frequent and proper washing of the hands and all those foods that have to be consumed. If you work in laboratories, take special care in the handling of biological samples and bacterial cultures.

IV Parasites

Although there are many important parasites, I am only going to mention Toxoplasma Gondii , the causative agent of Toxoplasmosis, since this is one of the parasitic infections best described and frequently involved in fetal injuries.

Toxoplasma is a parasite of felines that accidentally infects humans, as the human is not a suitable host the parasite remains in our tissues without the possibility of developing the infectious form that is expelled in the feces. This permanence of the intermediate form produces inflammatory reactions of little consequence in an immunocompetent individual but can generate severe lesions in a fetus with immature organs and high speed of development.

There is no cure for toxoplasmosis so, once acquired, will live with us the rest of our days but in reality will not bother at all under normal conditions. What one expects as an obstetrician is that the patient is positive before pregnancy since the infection only affects the fetus when it is acquired for the first time during pregnancy especially in its early stages. There are no vaccines and the treatment is only partial.

Prevention : adequate personal hygiene. If you are chronic, nothing happens. Avoid contact with cats or their feces, do not neglect the frequent washing of the hands and do not consume raw, poorly cooked or of dubious origin (street foods)

Exposure to Physical-Chemical Agents

I Chemical Agents :

Coffee, Tea and other drinks with caffeine, chocolate: in reasonable and relatively low doses there is no contraindication to the use of these beverages. The recommendation of the American School is to consume less than 200 mg of caffeine per day in any of its forms. Tea (4 cups): 50 mg. Coffee (1-2 cups): 50-100 mg. Chocolate: 30 mg. Soft drinks: 37 mg. Higher doses may be associated with low birthweight and restricted growth, but the evidence is equivocal and inconclusive (ACOG Committee opinion 2015)

Cigarette: smoking during pregnancy alters the tissue oxygenation of the fetus, fills your body with toxic substances and modifies the blood supply of the pregnant uterus. The use of cigarettes (even in passive smoking) has been associated with low weight and premature babies. Avoid smoking during pregnancy and use this as the perfect excuse to stop smoking. Always think that your baby can not say if you agree that you smoke for him; then, it is foolish that you scold him for smoking when he is 14, total, he smoked before he was born! Nicotine patches can be used to achieve habit suspension. Recent publications suggest that the use of marijuana and tobacco atrophy the fetal cerebral cortex, especially in the frontal brain region.

Alcohol: alcoholic beverages can severely affect your baby, there is the so-called Alcoholic Fetal Syndrome that is characterized by multiple malformations, neurological problems and mental retardation. Do not do that to your baby. Since there is no “safe” dose of alcohol in pregnancy, it is best not to take it. Remember: selfishness for momentary pleasure can lead to permanent injuries and a future of deep sadness for you and suffering in your unborn child.

Medications: never use drugs without consulting your doctor, there is a wide variety of them that could affect your baby. The “natural” can be toxic and we do not know what they contain.

The FDA (Food and Drug Administration) classifies drugs according to their potential effect on the embryo and the fetus in five categories:

A : Adequate studies in pregnant women have shown no risk to the fetus in the first trimester of pregnancy and there is no evidence of risk in subsequent quarters.

B : Studies in animals have not shown adverse effects on the fetus, but there are no adequate clinical studies in pregnant women.

C : Studies in animals have shown an adverse effect on the fetus, but there are no adequate clinical studies in pregnant women. The drug can be useful in pregnant women despite their potential risks.

D : There is evidence of risk to the human fetus, but the potential benefits of use in pregnant women may be acceptable despite the potential risks.

X : Studies in animals or humans show fetal abnormalities, or reports of adverse reactions indicate evidence of fetal risk. The risks involved clearly outweigh the potential benefits.

The medications that we indicated in pregnancy are categories A and B , occasionally we use some of the C , rarely of the D and never of the X.

As of June 30, 2015 this classification will be changed to a more detailed one included in the package of the medication (in the USA), it will include relevant data on pregnancy use, breastfeeding, contraception and infertility. It is expected to make the prescription more secure. It is called Pregnancy and Lactation Labeling Rule

Work toxins: research your work environment to determine if you are exposed to toxic substances such as Mercury, Lead, Hydrocarbons, etc. If there is any danger, request a change of work area. Some patients with “risky” jobs should have blood studies to know their degree of contamination before getting pregnant (Preconception evaluation)

II Physical Agents:

Radiation: sources of X-rays or other ionizing radiation can affect your health and your baby’s. Use all measures of Hygiene and Industrial Safety or request a change of section if you work in an exposed medium. If you have to visit a Radiology Service, notify the staff about your condition so they can take the appropriate precautions. If radiological studies (a fracture, for example) are absolutely necessary, they can be carried out without fetal danger since modern equipment emits low doses and radiologists are very well trained for these cases

Ultrasound: sounds with frequencies above 20,000Hz, such as those used in fetal sonography, have no harmful effects on the fetus