Medication during pregnancy

Prescription medications and over-the-counter agents are commonly used during pregnancy.

In a study of 9546 pregnant patients 97.1% reported taking at least one medication during the pregnancy.

The most commonly reported classes of medications taken during pregnancy include: gastrointestinal or anti-emetic agents, antibiotics, pain relievers and analgesics.

30.5% of pregnant persons report having taken at least five medications during pregnancy.

In the study of 1,106,756 pregnant women enrolled in Medicaid, the medication most commonly prescribed were antibiotics.

The overwhelming majority of drugs submitted to the FDA for approval lack data related to pregnancy.

A long delay is common between approval of a new medication and accumulation of data of safety in pregnancy.

Medication safety use data in pregnancy is often not available until several years after availability of the medication.

Evaluation of medications during pregnancy is complicated by the fact that a period of organogenesis may be well underway before patients realize they are pregnant.

Pregnancy is frequently excluded from clinical trials of new agents due to concerns about the safety to the developing fetus.

Relatively few medications are known teratogens: of more than 20,000 medications approved in the US fewer than 100 are classified as having substantial concern during pregnancy.

Drugs and medications should be avoided while pregnant. 

Tobacco, alcohol, marijuana, and illicit drug use during pregnant may be dangerous for the unborn baby and may lead to severe health problems and/or birth defects.

In certain situations the risk of stopping a medication may be worse than risks associated with taking the medication while pregnant: diabetes, epilepsy.

Some dietary supplements are important for a healthy pregnancy, while, others may cause harm to the unborn child.

In the United States reports that there are six million pregnancies with at least 50% of the women taking at least one medication.

A reported 5–10% of women of childbearing age use alcohol or addictive substances: recreational drug use can have serious consequences to the health of the mother, but also the fetus as many medications can cross the placenta and reach the fetus. 

These consequences on the babies include: physical abnormalities, higher risk of stillbirth, neonatal abstinence syndrome, sudden infant death syndrome (SIDS), and others.

Diabetes: Medications that can be used in diabetes during pregnancy include insulin, glyburide and metformin.

Pain Medications: 

Over-the-counter pain-relieving medications include aspirin, acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs).

The safety of these medications vary by class and by strength.

Prescription medications containing opioids while pregnant may cause serious harm to the mother or unborn child.

There is no established association with teratogenicity or elevated occurrence of birth defects and the usage of acetaminophen at any point during a pregnancy.

Acetaminophen use during pregnancy is not associated with risk of autism, ADHD, or intellectual, disability in children.

However, there is potential for fetal liver toxicity in cases of maternal overdose, where the mother consumes more than the recommended daily dose.

Non-steroidal anti-inflammatory medications (NSAIDs): studies do not show increased risk of spontaneous abortion within the first six weeks of pregnancy.

All NSAIDs show association with structural fetal cardiac defects with usage during the early weeks of pregnancy and their use is not recommended.

The anti-depressant paroxetine should be avoided during the first trimester due to concerns about fetal heart malformations.

Certain opioids may cause withdrawal symptoms in newborns, and all opioids should be used with caution during breast-feeding, due to the potential to suppress an infant breathing.

When ibuprofen and naproxen are used within the third trimester, there is a significant increase in the risk of premature closure of the ductus arteriosus with primary pulmonary hypertension in the newborn: it is recommended that pregnant women avoid these medications or use them sparingly.

Usage of aspirin during pregnancy is not recommended. 

Aspirin use during pregnancy has not demonstrated an increased risk of spontaneous abortion, however, its usage during organogenesis and the third trimester can lead to elevated risk of intrauterine growth retardation and maternal hemorrhage.

Opioids may be dangerous for the unborn baby and should not be taken while pregnant.

Most women with epilepsy deliver healthy babies and have a healthy pregnancy.

Some women with epilepsy are at a higher risk for stillborn and of the baby having birth defects such as neural tube defects.

Valproic acid and its derivatives such as sodium valproate and divalproex sodium may cause congenital malformations, and  an increased dose causes decreased intelligence quotient, while it increases the risk of neural tube defects by approximately 20-fold.

80% of pregnant women have experienced heartburn by the end of their third trimester.

Common antacids include aluminum hydroxide/magnesium hydroxide (Maalox) and calcium carbonate (Tums): they do not cross the placenta and are regarded as safe pharmacological options since there are no significant association with maldevelopment or injury to fetus.

Histamine H2 blockers and proton pump inhibitors, can also be used to help relieve heartburn, with no known teratogenic effects or congenital malformations.

Aluminum hydroxide/magnesium hydroxide and calcium carbonate, when consumed, do not cross the placenta and are regarded as safe pharmacological options to treat heartburn, since there are no significant association with maldevelopment or injury to fetus.

Pregnancy increases the risk of clot formation in women due to elevated levels of clotting factors and the risk increases even more immediately after birth and remains elevated up to 3 months after delivery.

In pregnant women, warfarin is contraindicated and should be avoided as it crosses the placental barrier, and has a risk of harming the fetus.

It has been shown that daily warfarin doses up to 5 mg may be beneficial for pregnant women who are at higher risk of thromboembolism.

Low molecular weight heparin  enoxaparin is listed as Pregnancy Category B, meaning animal studies have failed to show harmful effects to the fetus and therefore are safe to use in pregnant women.

Unfractionated heparin is classified as Pregnancy Category C: animal studies have shown potential for adverse effects to the fetus.

UFH can be used in pregnant women as long as the benefits outweigh the risk.

There is not enough evidence to demonstrate the safety and efficacy of DOACs in pregnant women.

Currently, rivaroxaban (Xarelto), dabigatran (Pradaxa), and edoxaban (Savaysa) are DOACs listed under Pregnancy Category C, and apixaban (Eliquis) is listed under Pregnancy Category B.


Bismuth subsalicylate had an increased risk for intrauterine growth retardation, fetal hemorrhage, and maternal hemorrhage within organogenesis in the second/third trimester.

Loperamide has an association with cardiovascular malformation in the first trimester.

Antihistamines: First generation antihistamines have the ability to cross the blood-brain barrier which can result in sedative and anticholinergic effects while effectively treating allergic reactions and nausea and vomiting related to pregnancy. 

Second generation antihistamines do not cross the blood-brain barrier, thus eliminating sedating effects. 

No association between prenatal antihistamine exposure and birth defects, and  during pregnancy they have not been linked to birth defects.

ACE inhibitors and ARB have known fetotoxicities when used during the second or third trimester or both: 

kidney damage or failure, oligohydramnios, anuria, joint contractures, and hypoplasia of the skull.

Agents for high blood pressure in pregnant women include anti-adrenergic and beta-blocking medications, such as methyldopa or metoprolol, respectively.


Decongestants in combination drugs or isolated forms are suggested to be used sparingly during pregnancy. 

Dietary supplements such as folic acid and iron are important for a healthy pregnancy.

Alcohol should not be consumed while pregnant. 

Even a small amount of alcohol is not known to be safe for the unborn baby, as alcohol passes easily from the mother’s bloodstream through the placenta and into the bloodstream of the fetus. 

The fetus is smaller and does not have a fully developed liver, the concentration of alcohol in its bloodstream lasts longer, increasing its detrimental side effects.

The effect  alcohol may have on a developing fetus depends upon the amount and frequency of alcohol consumed as well as the stage of pregnancy. 

Heavy drinking and binge drinking are associated with a higher risk of fetal alcohol spectrum disorders (FASDs). 

The most severe form of FASD is fetal alcohol syndrome (FAS). 

FAS is characterized by slower physical growth, facial abnormalities including smooth philtrum, thin vermilion, and short palpebral fissures, neurological deficits, or smaller head circumference. 

Delayed or uncoordinated motor skills, hearing or vision problems, learning disabilities, behavior problems, and inappropriate social skills compared to same-age peers are also associated with fetal alcohol spectrum disorder.

Fetal alcohol spectrum disorder patients 

are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and develop substance use disorders themselves.

Caffeine: an acceptable intake of caffeine for pregnant women is less than or equal to 200 mg per day.

Consumption of caffeine is not associated with adverse reproductive and developmental effects.

The half-life of caffeine is longer in pregnancy by 8 to 16 more hours.


Use  during pregnancy should be avoided.

There is no known safe dose of cannabis while pregnant.

Use of cannabis may lead to birth defects, pre-term birth, or low birth weight.

Tetrahydrocannabinol (THC), an active ingredient in cannabis, can both cross the placenta and accumulates in high concentrations in breast milk.

Cannabis consumption in pregnancy might be associated with restrictions in growth of the fetus, miscarriage, and cognitive deficits.

Newborns exposed to prenatal cannabis may show signs of increased tremors and altered sleep patterns.

Cannabis is the most frequently used, illicit drug amongst pregnant women.


Use of cocaine in pregnancy is dangerous and can lead to cardiovascular complications like hypertension, myocardial infarction and ischemia, kidney failure, liver rupture, cerebral ischemia, cerebral infarction, and maternal death.

Cardiac muscles become more sensitive to cocaine in the presence of increasing progesterone concentrations of pregnancy.

Cocaine use in pregnancy leads to increased risk for perinatal outcomes: preterm delivery, low birth weight, or reduced birth rate, small size, earlier gestational age at delivery, birth defects, and attention deficit hyperactivity disorder (ADHD).


Methamphetamine use is dangerous for pregnant women and to the unborn baby.

Methamphetamines cross  the placenta and affects the fetus during the gestational stage of pregnancy.

Methamphetamine use in pregnancy may lead to babies born with pre-term delivery, lower birth weight,  smaller head circumference, negatively impacts brain development and behavioral functioning and increases the risk of the baby having ADHD and lower mental processing speed.


Opioids such as heroin, fentanyl, oxycodone and methadone should not be taken while pregnant as they may cause adverse outcomes for the women and unborn child.

Women who use opioids during pregnancy at a higher risk for premature birth, lower birth weight, still birth, specific birth defects, and neonatal abstinence syndrome.

Opioids can cross the placenta and the blood brain barrier to the fetus, and are the main cause of neonatal abstinence syndrome.

The neonatal abstinence syndrome refers to the newborn baby experiencing withdrawal from the opioid they were exposed to during the pregnancy. 

The neonatal abstinence syndrome symptoms may include: tremors, convulsions, twitching, excessive crying, poor feeding or sucking, slow weight gain, breathing problems, fever, diarrhea, and vomiting.


Smoking during pregnancy is dangerous to the unborn baby and may cause pre-term birth, birth defects such as cleft lip or cleft palate, or miscarriage.

Tobacco is the most commonly used substance among pregnant women, at 25%, and nicotine crosses the placenta and accumulates within fetal tissues. 

Children born to women who smoked heavily are more susceptible to behavioral problems such as ADHD, poor impulse control, and aggressive behaviors.

Tobacco contains carbon monoxide, which has the potential to prevent the fetus from receiving sufficient oxygen. 

Tobacco poses risks of premature birth, low birth weight, and an increased risk of sudden infant death syndrome (SIDS) of up to three times compared to infants not exposed to tobacco.

Smoking and pregnancy, combined, cause twice the risk of premature rupture of membranes, placental abruption and placenta previa. 

Women in general who smoke heavily are less likely to become pregnant.

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