Metoprolol Use During Early Pregnancy: Weighing The Risks And Benefits

is metoprolol safe in early pregnancy

Metoprolol is a medication used to treat high blood pressure, fast heart rate, and migraines. It is part of a class of medications known as beta-blockers. While metoprolol has not been found to increase the risk of congenital malformations, it has been associated with reduced growth of the baby. Animal studies have also revealed increased post-implantation loss, fetolethality, and decreased neonatal survival. Therefore, it is recommended that metoprolol only be used during pregnancy if clearly needed and at the lowest possible dose. Exposure to metoprolol during pregnancy would not usually be regarded as medical grounds for termination, but careful monitoring of fetal growth is advised.

Characteristics Values
Should it be used during pregnancy? Only if clearly needed.
US FDA pregnancy category C
AU TGA pregnancy category C
Miscarriage risk Not known
Birth defects risk Not known
Reduced growth of the baby Observed
Neonatal symptoms Slowed heart rate and low blood sugar
Breastfeeding Passes into breast milk in small amounts

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Metoprolol is a beta-blocker used to treat high blood pressure, fast heart rate, and migraines

Metoprolol is typically used to treat the following:

  • High blood pressure (hypertension): Lowering high blood pressure helps prevent strokes, heart attacks, and kidney problems.
  • Chest pain (angina): Metoprolol can be used to prevent chest pain and improve survival after a heart attack.
  • Heart failure: Metoprolol can lower the risk of death or hospitalization due to heart failure.
  • Heart attack: Metoprolol injection is used during the early phase of a heart attack to lower the risk of death.
  • Migraines: Metoprolol can help prevent migraine headaches, but it should not be used to treat migraines when they occur.

While metoprolol is a useful medication for these conditions, it is important to note that it should not be used by individuals with certain serious heart problems, severe circulation problems, severe heart failure, or a history of slow heartbeats that have caused fainting. Additionally, pregnant women should consult their healthcare providers before taking metoprolol, as it may have potential risks for the unborn baby.

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Animal studies have shown increased post-implantation loss and decreased neonatal survival

Animal studies have revealed that the use of Metoprolol during pregnancy may lead to increased post-implantation loss and decreased neonatal survival. Metoprolol is a medication used to treat high blood pressure, fast heart rate, and migraines. While it is important to consult with healthcare providers before making any changes to medication, the potential risks of Metoprolol use during pregnancy should be carefully considered.

The drug has been associated with an increased risk of post-implantation loss, which refers to the loss of an embryo or fetus after it has implanted in the uterus. This can occur due to various factors, including genetic abnormalities, issues with the uterus or placenta, or exposure to certain substances. In the case of Metoprolol, animal studies have indicated a potential link between the drug and increased post-implantation loss, although the specific mechanisms are not yet fully understood.

Additionally, studies in animals have also shown decreased neonatal survival rates when the mother was administered Metoprolol during pregnancy. Neonatal survival refers to the ability of a newborn to survive beyond the first 28 days of life. This critical period is when newborns are most vulnerable, and any disruptions to their development or exposure to harmful substances can have detrimental effects on their survival. The exact reasons for the decreased neonatal survival rates in the studies are not clear, but it highlights a potential risk associated with Metoprolol use during pregnancy.

It is important to note that these findings are based on animal studies and may not directly translate to humans. However, they do raise concerns about the potential impact of Metoprolol on pregnancy outcomes. Healthcare providers must carefully weigh the benefits of treating a condition against the potential risks to the fetus and newborn when deciding whether to prescribe Metoprolol during pregnancy. In some cases, the benefits of the medication may outweigh the risks, especially if the condition being treated poses a greater threat to the pregnancy.

Furthermore, it is worth mentioning that there are limited data from human pregnancies regarding the effects of Metoprolol. While animal studies provide valuable insights, the effects on human pregnancies may differ due to physiological differences between species. More research is needed to fully understand the impact of Metoprolol on human pregnancy outcomes, including post-implantation loss and neonatal survival.

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There is no evidence of an increased risk of congenital malformations

Metoprolol is a medication used to treat high blood pressure, fast heart rate, and migraines. It is part of a class of medications known as beta-blockers. While it is important to talk to a healthcare provider before starting or stopping any medication during pregnancy, there is currently no evidence of an increased risk of congenital malformations associated with the use of metoprolol during early pregnancy.

Animal studies have not reported an increased chance of birth defects, and a study of a large number of pregnancies found that beta-blockers in general did not increase the chance of heart defects. There are no published data on overall rates of congenital malformation following metoprolol use in pregnancy. However, single case-control studies found no associations between first-trimester metoprolol exposure and hypospadias and posterior cleft palate, respectively. These findings suggest that metoprolol does not increase the risk of congenital malformations when taken during early pregnancy.

In the United States, metoprolol is classified as a Pregnancy Category C drug, which means that animal reproduction studies have shown an adverse effect on the fetus, but there are no adequate and well-controlled studies in humans. The recommendation is that this drug should be used during pregnancy only if clearly needed and, if used, it should be discontinued at least 2 to 3 days prior to the expected delivery date.

While there is no evidence of an increased risk of congenital malformations, there are some other considerations regarding the use of metoprolol during pregnancy. For example, metoprolol has been associated with reduced growth of the baby, but it is unclear if this is due to the drug itself or other factors. Additionally, use of beta-blockers near term may result in neonatal bradycardia, hypotension, and hypoglycaemia. Therefore, it is important for pregnant women taking metoprolol to be carefully monitored by their healthcare providers.

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Metoprolol use has been associated with reduced growth of the baby

Metoprolol is a medication used to treat high blood pressure, fast heart rate, and migraines. It is part of a class of medications known as beta-blockers. While metoprolol does not seem to pose a major teratogenic risk, its use has been associated with reduced growth in the baby. This could be due to the metoprolol itself, the health condition being treated, other factors, or a combination of factors.

The association between metoprolol use and reduced fetal growth has been observed in studies. However, the limited data currently available does not provide convincing evidence that metoprolol exposure in utero has clinically relevant effects on fetal growth. More studies are needed to fully assess this risk. In the meantime, careful monitoring of fetal growth is advised for pregnancies where maternal hypertension is present and/or metoprolol has been administered.

While there is no clear evidence of an increased risk of congenital malformations, metoprolol use during pregnancy, especially in the late stages, may cause symptoms such as a slowed heart rate and low blood sugar in the baby. Animal studies have also shown increased post-implantation loss, fetolethality, and decreased neonatal survival. Therefore, it is recommended to use metoprolol during pregnancy only if clearly needed and to administer the lowest possible dose. If possible, it is advised to discontinue the use of metoprolol 2 to 3 days before the expected delivery date.

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Metoprolol passes into breast milk in small amounts

The excretion of beta-adrenergic blocking drugs, such as metoprolol, into breast milk is largely determined by their protein binding. Those with low binding are more extensively excreted into breast milk. Metoprolol has a protein binding of 10%, which is considered low, and is therefore excreted into breast milk in small amounts.

It is important to monitor breastfed infants for symptoms of beta blockade such as bradycardia and listlessness due to hypoglycemia. However, studies on the use of metoprolol during breastfeeding have not reported any adverse reactions or side effects in breastfed infants.

In one study, metoprolol was undetectable in the plasma of 3- to 5-day-old breastfed infants after maternal doses of 50 or 100 mg twice daily. In another study, a woman who was taking 100 mg of metoprolol daily for hypertension during pregnancy and postpartum had undetectable levels of metoprolol and its active metabolite, alpha-hydroxymetoprolol, in her breastfed infant's serum on days 4 and 182 postpartum.

Overall, while metoprolol does pass into breast milk in small amounts, it is not expected to cause any adverse effects in breastfed infants.

Frequently asked questions

It is not known if metoprolol can make it harder to get pregnant.

Miscarriage can occur in any pregnancy and studies have not been done to see if metoprolol increases this risk.

Animal studies have not reported an increased chance of birth defects. A study of a large number of pregnancies found that beta-blockers did not increase the chance of heart defects. However, there is limited data on metoprolol specifically.

Reduced fetal growth has been observed following exposure to other beta-blockers, but the limited data on metoprolol does not currently provide convincing evidence of this effect.

Metoprolol is a category C drug in the US, meaning animal studies have shown an adverse effect on the fetus but there are no adequate studies in humans. It should be used during pregnancy only if clearly needed and with the lowest possible dose.

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