It is difficult to monitor how long opiates stay in a baby's system during pregnancy because it is not easy or ethical to do such studies on a human fetus. In addition, finding opiates in a newborn's system can't predict exactly when he was exposed. How long an opiate stays in a fetus or newborn is complicated and depends on several factors.
Opiates and the Fetus
According to researchers from the University Hospital Zurich and others, the characteristics of opiates allow them to cross the placenta into the fetus within an hour of maternal use. How soon an opiate gets into fetal tissues and how long it stays in his system depends on complex factors.
What Influences Opiates in a Fetus?
In the absence of human fetal testing, many conclusions on the factors that influence how the human fetus handles opiates come from work with pregnant sheep and other lab studies. According to the textbook Maternal Substance Abuse and the Developing Nervous System, after a maternal opiate dose, the following factors can influence how long the drug stays in the fetus:
- The type of opiate and how quickly the fetus metabolizes it:
- Short-acting opiates, such as heroin, won't stay in a fetus' system long. Short-acting opiates are more rapidly metabolized by the liver and excreted into the fetus' urine and stool.
- Longer acting opiates, such as methadone, are metabolized slowly and will stay in his system longer.
- The dose of opiate used and how frequently the woman takes it has a profound effect on how quickly opiates are metabolized.
- Other drugs present can affect how quickly an opiate gets metabolized or gets across the placenta to the fetus.
- The health of the placenta can be affected by medical problems such as diabetes; this will affect how much drug gets into the fetus.
- As a pregnancy advances into the third-trimester, drugs metabolize more quickly and less gets into the fetus.
- Genetic factors in the fetus can determine how quickly he metabolizes an opiate and excrete it in his urine and stool.
Effects of Opiates on Pregnancy and the Fetus
According to the authors of Maternal Substance Abuse and the Developing Nervous System, there are two main sources of opiate effects on the fetus:
- Direct effects on the development of the fetal nervous system, the behavior and health of the fetus, and the outcome of the pregnancy.
- Decrease in the function of the placenta which in turn affects the nourishment, growth and development of the fetus.
Effect on Fetal Nervous System and Behavior
According to Maternal Substance Abuse and the Developing Nervous System reference, at low doses and intermittent use, opiates excite the central nervous system but suppress it at higher and prolonged doses. Some of the fetal functions affected include:
- Breathing pattern
- Heart rate
- Sleep-wake cycles, resulting in disturbed sleep pattern
- Brain EEG patterns
Opiate Dependence and Withdrawal
As in the mother, prolonged exposure to opiates can lead to a physical drug dependence in the fetus. The fetus will also show signs of withdrawal if the mother misses a dose. Fetal opiate dependence is associated with increased risk of fetal death. Physical dependence and withdrawal are less likely with adequate methadone maintenance treatment of the mother during pregnancy.
Effects on Pregnancy Outcomes and Fetal Growth
According to the American Congress of Obstetricians and Gynecologists, if you take opiates during pregnancy, or abruptly stop them, you increase the risk of:
- Miscarriage and stillbirth
- Preterm labor and preterm birth
- Premature rupture of membranes
- Premature separation of the placenta
- Passage of meconium with a risk of meconium aspiration
- Poor intrauterine growth of the fetus, resulting in low birth weight of the baby
Pregnant women who are maintained on methadone substitution therapy throughout pregnancy are at less risk for preterm birth or low birth weight babies. There is inconclusive evidence of an increased risk of birth defects with maternal use of any opiate, but there might be a small risk in the first trimester.
Opiates and the Newborn
An opiate might still be detectable in a newborn's system at birth. According to the American Academy of Pediatrics (AAP), whether it's present and detectable at birth and how long it stays in his system after that depends on:
- Which specimen is used for drug detection in the newborn
- The opiate and how quickly the drug is metabolized by the fetal liver and excreted in the urine out of the baby's system
- When the mother took her last dose
- How long the mother took the drug during pregnancy
Some opiates, such as heroin, are quickly metabolized and may not be detectable in a newborn's urine or blood shortly after birth, but evidence of long-term exposure may be detectable in other specimens.
Detecting Opiates in the Newborn
According the American Association of Pediatrics reference, in the newborn "there is no biological specimen that, when obtained randomly, identifies prenatal drug use with 100% accuracy." In other words, if a specimen is negative it doesn't rule out recent drug exposure.
Each of the three most common specimens used to detect opiates and other drugs in the newborn gives a general, not a specific, idea of how long the baby was exposed:
- Urine: Urine is the most frequently used specimen for detecting recent exposure to opiates in a newborn. The presence of opiates in urine right after birth reflects use by the mother within a few days of delivery. Urine testing is quick, but a negative result does not rule out the possibility that the mother used opiates during pregnancy, especially if the newborn's urine sample is small in the first day of life.
- Meconium: Opiates in meconium can reflect exposure in the past several months, but results take a few days. Opiates and other drugs are thought to collect in meconium from the second trimester on. The accuracy of the results can be affected by the amount of the stool and when it is collected.
- Hair: The presence of drugs in hair reflects several months of exposure as substances stay in hair a long time. Testing is not as simple, and other contaminants in the sample can affect the results of the screening for opiates.
Detecting opiates in umbilical cord blood immediately at birth reflects recent maternal use and fetal exposure but cannot pinpoint when a drug was taken or how long it was in the fetal system.
Effects of Opiates on the Newborn
According to the AAP reference, effects of maternal opiate use during pregnancy can be seen in a newborn and may have lasting effects. Continuing problems for drug addicted babies include hyperactivity, poor sleep patterns, short attention span, and poor memory in childhood.
The most significant problems for an opiate-exposed newborn are neonatal abstinence syndrome, an increased risk of newborn death or sudden infant death syndrome (SÌDS).
Neonatal Abstinence Syndrome
The neonatal abstinence syndrome (NAS) includes irritability, poor feeding, dysfunctional sleep and high-pitched crying. It occurs when the opiate-dependent newborn is withdrawn from the mother's opiates at birth. The syndrome can be severe and a baby with NAS can spend several weeks in a hospital.
How soon NAS occurs and its severity depends on when the mother last used the opiate, how quickly the drug gets out of a baby's system and which opiate the mother used.
- Short-lasting opiates: Newborns exposed during pregnancy to short acting opiates, such as heroin or Percocet, or the opiate replacement buprenorphine, will have withdrawal symptoms within 48 to 72 hours.
- Longer-acting opiates: With opiates such as methadone withdrawal starts later, usually three to seven days after birth, and is more severe.
Statistics from the National Institute on Drug Addiction note that between 2000 and 20 12 the incidence of neonatal abstinence syndrome increased five-fold, accompanying a similar increase in maternal use of illicit and prescription opiates during pregnancy.
Give an Accurate History
Many factors affect how long opiates stay in a baby's system. Because use of opiates during pregnancy can affect your baby's health before and after birth, give your doctor or midwife an accurate history of your drug use so they can provide you and your baby with the right care and services.