Antibiotics in Pregnancy - Safe or Dangerous?

Pregnant women can take antibiotics? Antibiotics are safe during pregnancy? What to do when pregnant have an infection and need treatment?

Antibiotics in pregnancy
Antibiotics in pregnancy

With the increasing prevalence of chronic diseases and the expansion of the arsenal of antibiotics to treat infections, it is increasingly common to use drugs during pregnancy. Although feared, not all medications taken during pregnancy is necessarily dangerous. In many situations, such as in cases of infections, medications are needed for the welfare of the mother and fetus. One case of urinary tract infection in pregnant, for example, is much more harmful to the fetus than the possible adverse effects of antibiotics.

We must not forget, however, that about 3% of birth defects are still caused by improper use of drugs during pregnancy, especially when they are administered in the first quarter, the stage where the fetus is in the making.

In this article we do a quick review on the benefits and dangers of using antibiotics in pregnancy.

Antibiotics do harm?

Before we talk specifically the prescription of antibiotics in pregnancy, you must first take down some myths about the use of antibiotics in general.

The advent of antibiotics was one of the greatest revolutions of humanity. Diseases which killed millions of people over the centuries have become easily controlled with a treatment consisting in many cases, in making tablets for 7 or 10 days. Nowadays no one cares with an epidemic of bubonic plague and potentially fatal diseases, such as syphilis and tuberculosis, despite still being frequent, have a dramatically lower mortality rate than in the early twentieth century.

Antibiotics are in principle extremely beneficial to the population drugs. The problem with antibiotics arises when its use is done indiscriminately or injudicious. As with any medicine, antibiotics should only be prescribed when there is a clear indication. To prescribe an antibiotic, the doctor needs to know its antimicrobial action spectrum, their mechanisms of action, its adverse effect profile, their contraindications and microbial resistance profile of their community. If they are respected squeegees care, antibiotics will bring more benefits than harm to patients.

In the case of pregnant, the doctor also needs to know what are the safe antibiotics to the developing fetus. There are antibiotics that can be safely used at any time during pregnancy, but there are also those who are proven to be harmful to the fetus. If followed the guidelines, no need to be afraid to take antibiotics during pregnancy. Many antibiotics are allowed during pregnancy been used for decades without serious malformation have been identified problems.

Rating drugs during pregnancy

Just like any other drug, antibiotics are also given a classification according to their potential risk to the fetus. The most common way of classifying the safety of drugs in relation to pregnancy is through FDA classification, American drug agency:
  • Category A - drugs adequately studied in humans, which reveal no problems in the first trimester of pregnancy and there is no evidence of problems in the second and third quarters.
  • Category B - without appropriate drugs in human studies, but the experience in animal showed no risks or side effects of drugs in animals but when studied in humans show no risks.
  • Category C - drugs without adequate studies in humans, but that experience in animals has shown risks to the fetus. In such cases, potential beneficial effects of treatment may outweigh the risks, justifying its use during pregnancy in particular situations.
  • Category D - drugs with appropriate human studies that show evidence of risk to the fetus. They should only be given during pregnancy in cases of serious diseases for which it can not use safer drugs.
  • Category X - medicines with adequate human studies that demonstrate abnormalities in the fetus. Do not use under any circumstances during pregnancy.

There are several other ways to classify fetal risk of drugs, the FDA table was chosen in this article as one of the most common and simple.

Antibiotics during pregnancy

Let alphabetically list the main antibiotics and their respective risk rating. When necessary, I will make some observations.

To facilitate understanding, know that the drugs that fall in the categories A and B are those commonly used in pregnancy. In the case of antibiotics, there are no drugs classified in category A. Antibiotics used in pregnant women are those in category B, but this is not a problem because it is not expected that these drugs cause problems in the fetus.

Category C drugs are sometimes used, generally in specific situations when the drug is needed and there are no alternatives in category A and B.

Drugs classified as category D are contraindicated in pregnancy, and their use is accepted only in extreme situations, when the infection is at high risk to the fetus and there is no safer drugs available. In normal situations it is not acceptable to prescribe an antibiotic Category D for pregnant women.

Medicines classified as category X are those proven to cause malformations and in any case your prescription is accepted.

List of antibiotics - risk category in pregnancy

  • Amikacin - Category D
  • Amoxicillin - Category B
  • Amoxicillin + clavulanic acid - Category B
  • Azithromycin - Category B
  • Cefalotin - Category B
  • Cefazolin - Category B
  • Ceftriaxone - Category B
  • Cefuroxime - Category B
  • Ciprofloxacin - Category C
  • Clarithromycin - Category C
  • Clindamycin - Category B
  • Chloramphenicol - Category C
  • Doxycycline - Category D
  • Erythromycin - Category B
  • Streptomycin - Category D
  • Fosfomycin - Category B
  • Gentamicin - Category D
  • Levofloxacin - Category C
  • Metronidazole - Category B *
  • Minocycline - Category D
  • Neomycin - Category D
  • Nitrofurantoin - Category B **
  • Norfloxacin - Category C
  • Ofloxacin - Category C
  • Oxacillin - Category B
  • Benzathine penicillin - Category B
  • Penicillin V - Category B
  • Piperacillin + Tazobactam - Category B
  • Primaquine - Category C
  • Rifampicin - Category C
  • Sulfamethoxazole + trimethoprim - D Category ***
  • Tetracycline - Category D
  • Tobramycin - Category D
  • Vancomycin - Category B

* Metronidazole is contraindicated (Category X) in the first quarter. From the second quarter, it can be used in pregnant women.

** The nitrofurantoin is contraindicated (Category X) from the 38th week of gestation, because it is related to a high risk of hemolytic anemia in newborns.

*** In special situations, such as in the treatment of Pneumocystis jirovecii for the prophylaxis of toxoplasmosis, encephalitis and treatment of Q fever, sulfamethoxazole + trimethoprim can be prescribed for pregnant.

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