Is Phenergan Safe During Pregnancy?

pregnant woman feeling morning sickness

Morning sickness affects numerous pregnant women. Nearly 70 percent of pregnant women experience gastrointestinal symptoms like vomiting and nausea during their first three months of pregnancy, and Phenergan (medically known as promethazine) is an effective nausea-fighting drug commonly prescribed to counteract morning sickness.

Safety During Pregnancy

Women taking Phenergan during their first trimester or beyond may be concerned about its safety. In 1979, the United States Food and Drug Administration introduced a classification system for the use of prescription drugs during pregnancy. Classification categories are A, B, C, D, or X. Phenergan is a category C drug. As documented in the 4th edition of Drugs in Pregnancy and Lactation, for this category of medications, one of the following two is true:

  • Animal studies show adverse effects on the fetus and there are no controlled studies in women.
  • Studies in women and animals are not available.

In category C, drugs should be given only if the potential benefit outweighs the possible risk to the fetus.

Safety for Baby

Studies and correspondences from the FDA seem to focus on non-teratogenic effects, meaning those effects that do not directly affect the development of the fetus.

  • Dependence and withdrawal: Newborn dependence seems to be of most significant concern. It was reported in a negligible number of newborns whose mothers took this type of drug regularly during pregnancy, along with other drugs. The withdrawal signs may appear in the first few days after birth and include excessive crying, irritability, tremors, vomiting, and diarrhea.
  • Late-term neonatal respiratory depression for baby, universal respiratory depression for mother: Athena Health mentions pregnant mothers should take caution near term birth due to the possible risk of newborn respiratory depression. Respiratory depression is when an infant may not have fully developed lungs and has problems breathing on its own. According to a study by the Canadian Family Physician Journal, most infants who require resuscitation at birth clearly had the onset prenatally, as could be the situation with use of Phenergan during gestation.

  • Blood loss: There is a possible risk of maternal and newborn platelet aggregation impairment (the ability to form blood clots properly) when given Phenergen before and during labor based on limited human data. A study done by Children's Hospital Boston and Harvard Medical School informs that newborn babies with this syndrome, otherwise known as thrombocytopenia, will require ICU admission and platelet blood transfusions in an attempt to decrease the severity of bleeding.

Safety for the Mother

Phenergan side effects in pregnancy may also be potential for the mother. Along with the respiratory depression mentioned above, injected Phenergan also carries the risk of chemical irritation and tissue damage, with the most severe issue being tissue necrosis and gangrene, or the infection and decaying of skin. This may result from leaking of medication into the tissue surrounding the vein, unintentional injection into arteries, and injection of the drug into a nerve or surrounding nerve tissue, according to Epocrates. Surgical intervention may be required in some cases.

Nurse giving shot to patient

Can Phenergen Cause Birth Defects?

If a woman takes Phenergan while she's pregnant, it is unlikely that it will affect her developing baby. There does not appear to be any connection to Phenergan and birth defects. Studies have shown that there is no evidence of an increased risk of the birth defects when taken in the first trimester. The benefits of taking Phenergan appear to outweigh the risks when it comes to alleviating the symptoms of nausea and vomiting during pregnancy. If there are any questions, the doctor will discuss any concerns or any potential risks regarding this medication.

Making a Decision

If a doctor tells a pregnant woman Phenergan is safe during pregnancy, she may trust her doctor knows what's best for her and her baby, assuming the doctor is aware of the current research relating to the treatment of nausea and vomiting during pregnancy. It is always a good idea for a patient to do independent research before agreeing blindly to a new medication. Pregnant woman should make informed decisions about their health and the safety of their unborn babies. When making a decision, it is essential to weigh the benefits against the risks. Potential benefits include:

  • It prevents Hyperemesis gravidarum, a condition that causes severe vomiting, weight loss, and nutrient depletion and can make a woman so ill she is not even able to get out of bed, and she may lose a significant amount of weight. Besides vomiting, those affected may experience symptoms that include depression, dizziness, and fatigue.

  • It prevents extreme weight loss, which can negatively affect a baby's ability to grow while in the womb and is a serious health problem for both mom and baby.
  • It allows weight gain. If Phenergan controls nausea and vomiting for a pregnant woman and allows her to eat enough to gain weight and help her baby grow normally, the benefit of using the medicine may be worth the potential risks.
  • There appears to be no safety issues during birth to the mother. Despite listed risks, the FDA still lists "sedation during childbirth" as one of the approved uses of Phenergan.

The More You Know

The lack of definitive information on treatments for nausea during pregnancy, including Phenergan, can be frustrating for a pregnant woman trying to make treatment decisions. The best way to become informed is to research what studies say about the proposed treatment. This empowers expectant mothers to make informed decisions with the help of their doctors versus simply handing over responsibility for her baby and body to someone else. Once thoroughly informed, a mother should feel confident in knowing she has elected the best possible treatment measure for her and the baby to be.

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Is Phenergan Safe During Pregnancy?