THIS MEDICATION CAN CAUSE HARM TO YOUR BABY:
Aspirin should not be taken during the third trimester of pregnancy or within 1 week of delivery unless your doctor determines that it is absolutely necessary. Taking aspirin during the third trimester can cause heart abnormalities, bleeding problems, and death of the baby. Many experts also do not recommend the use of aspirin for treating pain or fever at any time during pregnancy. Several studies have associated aspirin with birth defects, miscarriage, low birth weight, intrauterine growth restriction, and death of the baby.
What is aspirin?
Aspirin is a pain reliever available as tablets and chewable tablets as well as some other formats. It is available with or without a prescription. Always ask your doctor before using any product containing aspirin.
What is aspirin used to treat?
Aspirin is used to treat fever and mild to moderate pain caused by headaches, arthritis, muscle aches, or menstrual periods. It can also be used to treat inflammation associated with some medical conditions, including arthritis and lupus. Additionally, daily low-dose aspirin is used as a blood thinner and can prevent heart attacks or strokes in people who have recently experienced one of these events.
How does aspirin work?
Aspirin decreases the production of some substances in the body that are involved in inflammation and blood clot formation. It also acts in the brain to dilate blood vessels and improve blood flow, which reduces fever.
If I am taking aspirin, can it harm my baby?
Aspirin crosses the placenta and may cause harm to your baby. The FDA warns that aspirin should not be used during the third trimester of pregnancy unless your doctor determines that treatment is absolutely necessary. Taking aspirin during the third trimester of pregnancy can cause premature closure of the ductus arteriosus. The ductus arteriosus is an artery present in the hearts of babies while they are in the womb. It redirects blood away from your baby’s lungs and back to the body. This is because your baby does not use their lungs while in the womb. Instead, your baby gets oxygen directly from the placenta. After delivery, your baby starts to breathe through the lungs, and the ductus arteriosus closes. If the ductus arteriosus closes before delivery, serious health problems can occur in your baby, including heart abnormalities, heart failure, persistent pulmonary hypertension, fetal hydrops (abnormal fluid accumulation in the body and around the organs), or death of the baby. In addition to the risk of premature closure of the ductus arteriosus, aspirin should not be taken within 1 week of labor and delivery because it can prolong labor and cause severe bleeding in the mom and baby.
Aside from the risks of aspirin use in the third trimester, taking aspirin during any trimester of pregnancy has been associated with intrauterine growth restriction (when babies are born smaller than normal for their age), bleeding abnormalities, and death of the baby. Higher doses of aspirin for treating pain or fever are not recommended for use in pregnant women. If pain therapy or a fever reducer is needed, alternative medications, such as acetaminophen, are recommended.
Although controversial, some experts consider low-dose aspirin (81 mg/day) safe for use during pregnancy. It has been used to manage some autoimmune diseases, such as antiphospholipid syndrome and lupus. It may also be beneficial for babies who are not growing properly in the womb and for expecting moms who are at risk for high blood pressure during pregnancy or preeclampsia. The American College of Obstetricians and Gynecologists (ACOG) has recommended the use of daily low-dose (60 to 80 mg) aspirin starting late in the third trimester for expecting moms who have a history of preeclampsia in more than one pregnancy or early-onset preeclampsia and premature delivery. The U.S. Preventative Services Task Force recommends the use of low-dose aspirin (81 mg/day) after 12 weeks of pregnancy for expecting moms who have a high risk for preeclampsia. Some experts have suggested that more studies are needed to determine if the benefits of low-dose aspirin treatment outweigh the potential risks. Your doctor will evaluate the potential risks of aspirin therapy and determine if low-dose aspirin is medically necessary.
Evidence and Risks
Taking aspirin regularly during pregnancy has been associated with low birth weight, death of the baby, and delivery complications (cesarean section).
Low-dose aspirin (81 mg/day) has been used in some moms with lupus to reduce the likelihood of miscarriage. Using low-dose aspirin for this purpose was not found to cause complications in the baby.
Some studies have looked at the effects of low-dose aspirin in preventing high blood pressure and preeclampsia in high-risk moms. Aspirin toxicity was not observed in babies after long-term use of low-dose aspirin for these purposes. Premature closure of the ductus arteriosus and other complications associated with aspirin therapy near delivery were also not observed. More studies are needed to determine the effects of low-dose aspirin for these purposes.
Aspirin has been associated with intrauterine growth restriction, aspirin toxicity, and persistent pulmonary hypertension in some studies and reports.
When aspirin is taken at doses of 325 to 650 mg the week before delivery, the clotting ability of the baby may be impaired. Bleeding complications have been observed in babies whose moms took aspirin within 1 week of delivery. The use of aspirin near delivery has also been associated with a higher rate of intracranial hemorrhage (bleeding in the skull) in premature or low birth weight babies.
A study that looked at 22 expecting moms who were exposed to aspirin at the time of conception or during pregnancy found a higher risk of miscarriage. This risk was greater if aspirin was taken near the time of conception and if the medication was taken for more than 1 week.
It is unclear if aspirin is associated with a higher risk of birth defects. Two large studies found that more moms who had a baby with a birth defect reported using aspirin compared to moms who delivered a healthy baby. Another study found a 3 times higher rate of aspirin use in the first trimester among moms who had a baby with oral clefts. One study found a higher risk of gastroschisis (a birth defect in the abdominal wall causing the intestines to be located outside of the body) in expecting moms who took aspirin. Studies have also found a possible association between aspirin and birth defects in the heart, but several other studies did not find a higher risk of birth defects in the heart or birth defects overall.
A study looked at pregnancy outcomes from the National Birth Defects Prevention Study for 4625 expecting moms who had taken any nonsteroidal anti-inflammatory medication, including 703 who took aspirin. Although the study concluded that nonsteroidal anti-inflammatory medications overall do not appear to be major teratogens, aspirin was associated with several specific birth defects, including birth defects in the brain, spinal cord, eyes, limbs, heart, and lip/mouth.
Taking full-dose aspirin during the first trimester of pregnancy has also been associated with a lower IQ in the newborn, but another study could not confirm this association.
Bottom line: Aspirin should not be taken during the third trimester of pregnancy or within 1 week of labor and delivery unless your doctor determines that it is ab
solutely necessary. Taking aspirin during the third trimester can increase the risk of bleeding, delivery complications, and a heart defect, which could cause death of the baby. Some experts advise against the use of higher dose aspirin to treat pain or fever at any time during pregnancy. Taking aspirin during pregnancy has been associated with several complications, including birth defects, toxicity, intrauterine growth restriction, low birth weight, and death of the baby.
If I am taking aspirin and become pregnant, what should I do?
If you become pregnant while taking aspirin, you should contact your doctor immediately. Some studies have associated the use of aspirin at the time of conception with a higher risk of miscarriage. Your doctor will determine if aspirin is medically necessary or if it should be discontinued.
If I am taking aspirin, can I safely breastfeed my baby?
It is not recommended to take some aspirin formulations while breastfeeding. Your doctor will evaluate the risks to your baby and determine if aspirin is medically necessary. The metabolite of aspirin (salicylate) passes into breast milk. Giving aspirin to infants is associated with Reye’s syndrome, but it is unknown if Reye’s syndrome can be caused by exposure to aspirin from breast milk. Alternative medications are preferred for treating moms who would require high-dose or long-term aspirin therapy. The American Academy of Pediatrics has classified aspirin as a medication that should be used cautiously by nursing moms because it has been associated with significant effects in breastfed babies. The data available on the effects of aspirin in the breastfed baby consists of only a few case reports and a small study. A report described a breastfeeding mom who was taking high-dose aspirin. Her baby developed a condition characterized by acidic blood, which was considered probably caused by aspirin exposure from breast milk. Another report described a breastfeeding mom who took aspirin for a fever. Five days later, her baby developed a fever, low platelet count, petechiae (red patches on the skin caused by bleeding), and lack of appetite. These symptoms were considered probably related to aspirin. One other report considered aspirin exposure from breast milk to be responsible for a blood disorder that developed in a breastfed baby. In a small study, 15 moms who took aspirin reported no side effects in their breastfed babies. Although high dose aspirin is not recommended by many experts, some experts consider low-dose aspirin (intended to prevent blood clots) to be mostly safe during breastfeeding.
Bottom line: Nursing is not recommended while taking some aspirin formulations. The metabolite of aspirin passes into breast milk. Several reports have described health problems that developed in breastfed babies who were exposed to aspirin. Your doctor will determine if aspirin is medically necessary or if an alternative medication should be prescribed.
If I am taking aspirin, will it be more difficult to get pregnant?
Low-dose aspirin can increase pregnancy rates in women suffering from chronic inflammation. A study found that low-dose aspirin increased live birth rates in women with high levels of high-sensitivity C-reactive protein (a protein in the blood that is an indicator of chronic inflammation) who had 1 or 2 previous pregnancy losses.
Aspirin may also make some birth control methods ineffective. Two cases described pregnancies in women who had intrauterine devices. Failure of the devices to prevent pregnancy was associated with the anti-inflammatory properties of aspirin.
If I am taking aspirin, what should I know?
Aspirin should not be taken during the third trimester or within 1 week before labor and delivery unless your doctor determines that it is absolutely necessary. Taking this medication during the third trimester can cause heart abnormalities, bleeding, and death of the baby. Some experts advise against the use of aspirin for treating pain or fever at any time during pregnancy. Several studies have observed a higher risk of birth defects, miscarriage, intrauterine growth restriction, low birth weight, and death of the baby with aspirin use.
Nursing is not recommended with some aspirin formulations. The metabolite of aspirin passes into breast milk. Several reports have described health problems in breastfed babies exposed to aspirin through breast milk.
If I am taking any medication, what should I know?
This report provides a summary of available information about the use of aspirin during pregnancy and breastfeeding. Content is from the product label unless otherwise indicated.
You may find Pregistry's expert reports about the individual medications used to treat pain here, our report about pain here, and our report about fever here. Additional information can also be found in the resources below.
For more information about aspirin during and after pregnancy, contact http://www.womenshealth.gov/ (800-994-9662 [TDD: 888-220-5446]) or check the following links.
American Heart Association: Patent Ductus Arteriosus (PDA)
Lexicomp: Aspirin: Drug Information
The American College of Obstetricians and Gynecologists: Hypertension in Pregnancy.