Pregnancy with Drugs

Pregnancy with Drugs

 

More than 90% of pregnant women take prescription or nonprescription (over-the-counter) drugs or use social drugs, such as tobacco and alcohol, or illicit drugs at some time during pregnancy. In general, drugs, unless absolutely necessary, should not be used during pregnancy, because many can harm the fetus. About 2 to 3% of all birth defects result from the use of drugs.

 

Drugs taken by a pregnant woman reach the fetus primarily by crossing the placenta, the same route taken by oxygen and nutrients, which are needed for the fetus's growth and development. Drugs can affect the fetus in several ways:

•          act directly on the fetus, causing damage, abnormal development (leading to birth defects), or death.

•           alter the function of the placenta, usually by reducing the supply of oxygen and nutrients to the fetus thus resulting in an underweight and underdeveloped baby.

•          cause the muscles of the uterus to contract forcefully, thus injuring the fetus by reducing its blood supply or triggering preterm labor and delivery.

 

Food and Drug Administration (FDA)

•          Thalidomide caused extreme underdevelopment of arms and legs and defects of the intestine, heart, and blood vessels in the babies

•          Meclizine taken for motion sickness, nausea, and vomiting; causes birth defects in animal.

•          Oral hypoglycemic drugs can cross the placenta and cause low blood sugar level in newborn; preferring use Insulin because not cross the placenta in diabetes in pregnancy.

•          Etretinate used to treat skin disorders, is stored in fat beneath the skin and is released slowly. It can cause birth defects 6 months or longer after women discontinue it. Therefore, women are advised to wait at least 1 year after discontinuing the drug before they become pregnant.

•          Antihypertensives may be needed by pregnant women who have had high blood pressure (a complication called preeclampsia), markedly reduce blood flow to the placenta if they lower blood pressure too rapidly in pregnant women.

•          Digoxin treats heart failure and some abnormal heart rhythms, readily crosses the placenta, has little effect on the baby before or after birth.

 

Some Drugs That Can Cause Problems During Pregnancy

•          Antianxiety Drug – diazepam

•          Antibiotics – chloramphenical, ciprofloxacin, kanamycin, nitrofurantoin, streptomycin, sulfonamides, tetracycline

•          Anticoagulants – heparin, warfarin

•          Anticonvulsants – carbamazepine, phenobarbital, phenytoin, trimethadione, valproate

•          Antihypertensives – angiotensin, thaiazide diuretic

•          Chemotherapy Drug – busulfan, chlorambucil, cyclophosphamide, mercaptopurine, methotrexate

•          Mood-stability Drug – lithium

•          Nonsteriodal Anti-inflammatory Drugs – aspirin, other salicylates

•          Oral hypoglycemics – chlorpropamide, synthetic progestins, diethylstilbestrol

•          <?xml:namespace prefix = st1 />Skin Tx – etretinate, isotretinoin

•          Thyroid Drugs – methimazole, propylthiouracil, radioative iodine

•          Vaccines – live virus vaccine, i.e. MMR, OPV, chicken pox, yellow fever

 

Social Drugs

Cigarette Smoking: The most consistent effect of smoking on the fetus during pregnancy is a reduction in birth weight.  Birth defects of the heart, brain, and face are more common among babies of smokers than among those of nonsmokers, including  sudden infant death syndrome (SIDS), miscarriages, deficiencies in physical growth and in intellectual and behavioral development. These effects are thought to be caused by carbon monoxide and nicotine.

Alcohol: leading known cause of birth defects. The risk of miscarriage, low birth weight about 4 pounds. Fetal alcohol syndrome is one of the most serious consequences of drinking during pregnancy. This syndrome includes inadequate growth before or after birth, facial defects, a small head, mental retardation, and abnormal behavioral development. Abnormal and heart defects are present. Babies of women who drank alcohol during pregnancy may have severe behavioral problems, such as antisocial behavior and attention deficit disorder.

Caffeine: harms the fetus is unclear. It is a stimulant that readily crosses the placenta to the fetus. Thus, it may stimulate the fetus, increasing the heart and breathing rates. Caffeine also may decrease blood flow across the placenta and decreases the absorption of iron (possibly increasing the risk of anemia). Drinking 7-8 cups or more/day increases the risk of having a stillbirth, premature birth, low-birth-weight baby, or miscarriage is also unclear.

Aspartame: Aspartame, an artificial sweetener, appears to be safe during pregnancy when it is consumed in small amounts, such as in amounts used in artificially sweetened foods and beverages. Not suggestion to use a lot.

 

Illicit Drugs

Use of illicit drugs (particularly cocaine and opioids) during pregnancy can cause complications during pregnancy and serious problems in the developing fetus and the newborn. Injecting drug using is Increasing the risk of infections that can affect or be transmitted to the fetus, hepatitis and STD (including AIDS). Fetus growth is more likely to be inadequate, and premature births are more common.

Cocaine: Cocaine readily crosses the placenta and affects the fetus. It constricts blood vessels, reducing blood flow (and the oxygen supply) to the fetus, particularly of the bones and the intestine. Rarely, use of cocaine results in birth defects of the brain, eyes, kidneys, and genital organs. Use of cocaine during pregnancy can also cause complications during pregnancy, about 31% have a preterm delivery and 15% have premature detachment of the placenta (placental abruption). Newborns may have withdrawal symptoms. Their behavior is also affected. Newborns interact less with other people. Babies of cocaine users may be hyperactive, tremble uncontrollably, and have difficulty learning (which may continue through age 5 years or even longer).

Opioids:  such as heroin, methadone, and morphine, readily cross the placenta. Consequently, the fetus may become addicted to them and may have withdrawal symptoms 6 hours to 8 days after birth. However, use of opioids rarely results in birth defects and increases the risk of complications, such as miscarriage, abnormal presentation of the baby, and preterm delivery. Babies of heroin users are more likely to be small.

Amphetamines:Use of amphetamines during pregnancy may result in birth defects, especially of the heart.

Marijuana:harm the fetus is unclear. The main ingredient of marijuana, tetrahydrocannabinol, can cross the placenta and thus may affect the fetus. If marijuana is used heavily during pregnancy, newborns may have behavioral problems.

 

Drugs Used During Labor and Delivery

Local anesthetics, opioids, and other analgesics usually cross the placenta and can affect the newborn. For example, they can weaken the newborn's urge to breathe. Therefore, if these drugs are needed during labor, they are given in the smallest effective doses

 

Resources

•          Drug use during pregnancy, The MERCK manual of medical information-second home edition, online version, http://www.merck.com/mmhe/index.html

•          Teenage pregnancy and drug abuse,

•          Illicit drug use in pregnancy, http://www.marchofdimes.com/professionals/14332_1169.as/

•          Drug abuse and treatment, National Women's Health Information Center, http://www.4woman.gov/

•          Alcohol research group, National research center, Public Heath Institute, http://www.arg.org/studies.html

 

Kris Trairatana