Frontiers in Anti-infective Agents

Infections in pregnancy still pose a challenge to public health, especially in less developed countries. They may occur in intrauterine life, and are classified as congenital, or during childbirth and immediate postpartum when they are known as perinatal infections. Infections that occur during pregnancy trigger mechanisms that may culminate in preterm labor, fetal malformations, and fetal and neonatal death. Recognition of signs and symptoms and early diagnosis are the key to reducing the damage that these infections can cause in the mother and the fetus. In this chapter, we will discuss the main infections, risks for maternal and fetal health and strategies that can be used to minimize harm.

Pregnancy is considered a special moment in a woman's life. However, in this period, physiological changes take place that make the woman more vulnerable to infectious agents. The use of medications in this period may pose risks to both the mother and the developing infant, and subsequently, common physiological changes interfere greatly with the dynamics and kinetics of the drugs. There is still a concern about possible toxic effects on the mother and fetus as well as possible teratogeny. This chapter aims to discuss the anti-infective agents to broaden the understanding of the fundamental concepts, practical applications of the drugs prescribed and the necessary care for pregnant women.

The use of medication during pregnancy represents a challenge for health professionals, since the incorrect use leads to harmful effects not only on the pregnant woman but also on the fetus. Most anti-infective agents administered to pregnant women cross the placental barrier and expose the developing fetus to their pharmacological effects, which may be teratogenic. Because of the relatively common occurrence of some infections during pregnancy, there is a great importance of studying them, therefore, knowing the classification of the drugs and identifying which agents are safe during pregnancy will both be discussed in this chapter.

Among the infections that can affect women during pregnancy, about 10% are represented by urinary tract infections (UTI), which are the most common type of infection during pregnancy. Depending on the part of the urinary tract they affect, they are known as Cystitis and Asymptomatic Bacteriuria, when they occur in the lower tract, or pyelonephritis when the infection in the lower tract ascends. All clinical types of UTI can lead to serious maternal and fetal complications. Thus, differently to the non-pregnant patient, all UTIs during pregnancy, including those with asymptomatic infection, need treatment. When we identify more than one episode in the same pregnancy, prophylactic treatment is recommended.

During pregnancy, the occurrence of Sexually Transmitted Infections (STI) is a problem aggravated by the presence of the fetus, which presents difficulties in the use of certain drugs and the physiological adaptations of this phase in the pregnancypuerperal cycle. The World Health Organization (WHO) estimates that 448 million new STIs worldwide occur each year, of which the most frequent are associated with human papillomavirus (HPV), Chlamydia trachomatis, Neisseria gonorrhoeae.

The use of antiretrovirals in pregnant women is mandatory to suppress HIV replication and prevent mother-to-child vertical transmission, and some drugs are available to compound such therapeutic regimens. Infectious disease specialists and obstetricians have to work together with the aim to diminish the teratogenic effects of each drug and to protect the fetus from the virus. Herein, the most popular antiretroviral drugs are discussed, regarding their mechanism of action, adverse events and safety of use in pregnancy.

This chapter discusses genital changes in the gestational period and their influences in the vaginal microbiome. Using the latest scientific evidence, the most common genital infections will be shown, as well as the best methods of diagnosis and the use of antibacterials agents in the gestational period, with their recommended strength.

Toxoplasmosis is a global parasitic disease that can be transmitted from mother-to-child when the infection is acquired for the first time during pregnancy. Clinical manifestations of congenital disease include retinochoroiditis, cerebral calcifications, and hydrocephalus. Prenatal testing for toxoplasmosis is routinely offered in many countries so that infected mothers can be treated with antibiotics to reduce the risk of mother-to-child transmission. The diagnosis of toxoplasmosis during pregnancy is complicated because determining whether infection occurred prior to conception or during pregnancy is critical, besides the fact that false-positive tests are common and that there is lack of standardization among these tests. If maternal infection is confirmed before 18 weeks of gestation and the fetus is not yet infected the use of spyramicin is recommended to prevent mother-to-child transmission, as this drug has a high concentration in the placenta and has no teratogenic effects. If infection is presumed or confirmed in the fetus, the treatment should be switched to pyrimethamine, sulfadiazine and folinic acid (PSF) until the end of the gestational period to prevent further damage to the newborn. When maternal infection is confirmed after 18 weeks of gestation, the use of PSF is required, and should be used until delivery. However, these drugs can present some adverse effects, such as paresthesia, pruritus, urticaria, diarrhea, nausea, and vomiting for spiramycin, and arrhythmia, erythema multiforme, pancytopenia, hematuria, and eosinophilic pneumonitis for pyrimethamine. There is an urgent need for having safer drugs on hand that are a suitable chemotherapy or prophylaxis for children and pregnant women, and further studies are needed to address this.

Natural remedies are widely used by pregnant women as they are perceived to be more “natural” and safe and also to avoid pharmaceutical treatment. Although some natural remedies can be used during pregnancy, some plants are not safe and for most of them, there is a lack of clinical evidence of safety. In addition, some natural remedies have a potential risk of herb-drug interactions. Many studies can be found in the literature, specifically on treating infections, but most are non-clinical studies. The main natural anti-infective remedies used by pregnant women are cranberry, echinacea, barberry, hydrastis, raspberry and garlic. The strongest clinical evidence was found in cranberry and echinacea, mainly to treat urinary tract infection recurrence and cold infection, respectively, these seem to be safe, but the efficacy is not clear. Natural remedies lack studies with methodological rigor conducted with standardized extracts with defined active compounds content for the guarantee of reliable results.