Final answer:
Psychoactive drugs can pass from a mother to her newborn through the placenta and breast milk. These drugs, along with other substances and infections known as teratogens, can cause significant harm to the developing fetus or infant, necessitating careful medical monitoring and management.
Step-by-step explanation:
Psychoactive drugs can pass from a mother to her newborn through the placenta and, to a different extent, through breast milk. Substances like heroin, cocaine, methamphetamine, prescription medicines, and even over-the-counter medicines are all considered teratogens. These substances can transfer from the mother to the fetus or infant, causing potential harm. Babies born with a dependency on drugs like heroin require careful medical supervision to be weaned off the substance to prevent serious complications, including seizures and death. Other teratogens include radiation, viruses such as HIV and herpes, and rubella (German measles). The transplacental transmission of pathogens or drugs can lead to a variety of harmful effects on the fetus including impairment in the development of major organs and systems, cognitive deficits, or even fetal death.
It is crucial for expecting mothers to avoid teratogens, particularly during the first eight weeks after fertilization when the major organs are forming. Exposure during this critical period can have life-long impacts on the child's health. Furthermore, infections like rubella and substance use such as smoking which contains nicotine, are also known to cause significant developmental challenges and health issues in the child.
Mothers also pass antibodies to their infants, either through the placenta or through breast milk. These antibodies provide passive immunity to the newborn against various diseases. However, the transmission of infectious diseases is also a risk, especially at birth if the mother has certain infections like chlamydia or gonorrhea.