Medications that can be used in pregnancy

The most commonly used drugs in pregnancy include antiemetic, antacid, antihistamine, analgesic, antimicrobial, tranquilizing, hypnotics, diuretics, and social and illegal drugs. The American Nutrition and Prescription Committee (FDA) classifies drugs in 5 safety categories for use during pregnancy. A well-controlled study of some therapeutic drugs during pregnancy was conducted. Most of the information on drug safety during pregnancy is obtained from experimental studies and uncontrolled studies in humans (for example, post-marketing reviews). During pregnancy, drugs are used to treat certain disorders. Despite the widespread concept of the safety of the use of medicines, their use, excluding alcohol, accounts for only 2-3% of cases of congenital malformations of the fetus; most developmental defects have genetic, environmental or unknown causes.

Categories of drug safety during pregnancy (fda)

Category	Description
A	During clinical studies, no dangerous effects on the embryo were identified; these drugs are the safest
AT	Animal studies indicate no risk to the fetus, but no clinical studies have been performed in humans; experimental animal studies indicate a risk of fetal exposure, but no controlled studies in humans have been conducted
FROM	Adequate studies in animals or humans have not been conducted; or an adverse effect on the fetus has been observed in animal testing, but human studies are not available
D	Fetal risk exists, but in certain situations, benefits may outweigh the risk (for example, life-threatening disorders, serious violations in which safer drugs can not be used or are ineffective)
X	The proven risks of influencing the fetus outweigh the benefits of the drug

Not all drugs taken by the mother penetrate the placenta to the fetus. Drugs can have a direct toxic or teratogenic effect (for known and suspected teratogenic factors). Those drugs that do not penetrate the placenta can harm the fetus in the following way: spasmodic placental vessels and, as a result, lead to disruption of the gas and nutrient metabolism; cause pronounced uterine hypertension, leading to an anoxic trauma; change the physiology of the mother (eg, causing hypotension).

Known or suspected teratogenic factors

ACE Inhibitors	Azotrethionine
Alcohol	Lithium
Aminopterin	Metamizol sodium
Androgens	Methotrexate
Carbamazepine	Phenytoin
Coumarins	Radioactive iodine
Danazol	Tetracycline
Diethylstilbestrol	Trimethadone
Etretinat	Valproic acid

The drugs penetrate the placenta like a way of penetrating them through other epithelial barriers. Whether the drug penetrates the placenta and how quickly it depends on its molecular weight, the connection with another substance (for example, the carrier protein), the availability of the exchange between villi and the amount of drug metabolized by the placenta. Most drugs with a molecular weight of less than 500 Da are able to penetrate the placenta and enter the fetal bloodstream. Substances of high molecular weight (for example, those associated with a carrier protein) usually do not penetrate the placenta. An exception is immunoglobulin G, which is sometimes used to treat disorders such as embryonic alloimmune thrombocytopenia. In general, the concentration equalization between maternal blood and fetal tissues takes at least 40 minutes.

The effect of the drug on the fetus is largely determined by the fetal age in the isolation, strength and dosage of the drug. Drugs used within 20 days after fertilization can produce an uncompromising effect, acting fatal to the embryo or not damaging it at all. Teratogenesis at this stage is unlikely, but more possible during organogenesis (between 14th and 56th days after fertilization). Drugs that penetrate the embryo during this period can lead to abortion, sublethal anatomical defects (true teratogenic effect) or secret embryopathy (permanent metabolic or functional defects that may appear later in life) or may have no effect. The drugs used after organogenesis (in the 2nd and 3rd trimester) are rarely teratogenic, but they can change the growth and function of normally formed fetal organs and tissues.

[1], [2], [3], [4], [5], [6], [7]

Vaccines and pregnancy

Immunization is just as effective in pregnant women, as in non-pregnant women. Vaccination against influenza is recommended for all pregnant women in the 2nd or 3rd trimester during the flu epidemic. Other vaccines should be used in situations where a woman and a fetus are at high risk of infection, with a low risk of adverse effects from the vaccine. Inoculations from cholera, hepatitis A and B, measles, mumps, plague, poliomyelitis, rabies, diphtheria, tetanus, typhoid and yellow fever can be used during pregnancy with a significant risk of infection. Live viral vaccines are not prescribed for pregnant women. A rubella vaccine, a weakened live virus vaccine, can cause subclinical placental and intrauterine infection. However, newborns were not found to have defects associated with rubella vaccination. Patients who were accidentally vaccinated in the early stages of pregnancy should not be recommended for interruption only on the basis of the theoretical risk of vaccination. Varicella is a weakened live virus vaccine that can potentially infect a fetus; The greatest risk is observed between the 13th and 22nd weeks of gestation. This vaccine is contraindicated during pregnancy.

Vitamin A and pregnancy

Vitamin A in the amount of 5000 IU / day, contained in prenatal vitamins, does not have a teratogenic effect. However, doses greater than 10,000 IU / day during early pregnancy may increase the risk of congenital malformations.

Social and illegal means

Smoking cigarettes and consuming alcohol or cocaine during pregnancy can cause significant problems in the fetus and the newborn. Although the main metabolite of marijuana can penetrate the placenta, the regional use of this substance does not increase the risk of congenital malformations, does not limit fetal growth and does not cause postpartum neurobehavioral disorders. Many mothers of children with congenital heart defects stop using amphetamines during pregnancy, suggesting a possible teratogenic effect.

The effect of consuming large amounts of caffeine on the increased risk of perinatal complications has not been elucidated. Consumption of caffeine in small quantities (for example, 1 cup of coffee a day) does not threaten the fetus, but according to some data that did not take into account the use of tobacco or alcohol, it is assumed that the consumption of large quantities (> 7 cups of coffee per day) increases the risk of stillbirth, premature births, birth of small children by the time of gestation and spontaneous abortions. Decaffeinated drinks theoretically reduce the risk from the fetus. The use of a dietary sugar substitute for aspartame during pregnancy is often questioned. The most common metabolite of aspartame, phenylalanine, comes to the fetus by active placental transport; toxic levels of it can cause oligophrenia. However, when using aspartame within normal limits, phenylalanine levels in the fetus are far from toxic levels. It is likely that moderate use of aspartame during pregnancy reduces the risk of toxic effects on the fetus. However, pregnant women with phenylketonuria use aspartame (and thus, phenylalanine) is prohibited.