What are the Effects of Teratogens on Premature Births

Premature birth is giving birth to a baby of less than thirty seven weeks gestation period. A baby has less time to develop and mature in the womb. Preemie babies have increased risk of various medical and developmental problems which include pradycardia, intraventricular hemorrhage, weighing less than full term babies, immature lungs, pneumonia, jaundice, patent ductus arteriosus sepsis, necrotizing enterocolitis, retinopathy of prematurity, apnea and mental retardation. These problems occur because their organs did not have enough time to develop. Premature babies need special medical care until time there organ systems can work on their own in a neonatal intensive care unit (NICU) which has specialized medical staff and equipment. A teratogen is any medication, chemical, infectious disease or environmental agent that a mother may be exposed to during her pregnancy which interferes with the normal embryonic development. A fetus is thought to be affected by teratogens about ten to fourteen weeks after conception as this is the period that the mother and embryo have a common blood supply.

Smoking and nicotine
Smoking during pregnancy increases the chances of preterm delivery. Smoking may also lead to a premature rupture of the membranes, a condition that almost always results in a premature birth. It may lead to sudden infant death syndrome. It also appears to increase the risk of women developing the placental problems that can contribute to premature birth. Nicotine depresses the appetite at a time the mother should be gaining weight. This results in insufficient nourishment for the fetus and hence reduced growth. Smoking reduces the ability of the lungs to absorb oxygen. Depriving the fetus of oxygen makes it not to grow as fast as it should and contribute to a decrease in quality for night-time sleep for the baby. Smoking causes problems with the brain, cardiovascular system and respiratory system like asthma as have smaller airways. Women who smoke during pregnancy give birth to babies who are lighter and smaller in all dimensions than babies of non-smokers. Smoking also affects the blood pressure of the developing baby. This in turn affects its development and its learning abilities.

Alcohol
Alcohol contributes to birth of pre-mature babies who have behavioral, neurological and skeletal problems. Alcohol breaks down into a cell damaging compound in the mothers body which is readily absorbed by the fetus. Alcohol consumption during pregnancy leads to a cluster of birth defects known as fetal alcohol syndrome. This pattern of malformations is comprised of microcephaly (small skull), abnormal facial features, heart defects, mental retardation, impeded growth, hyperactivity and learning disabilities. This is because it interferes with the nutritional process by limiting the digestion and storage of important nutrients that a baby requires to develop normally. Even moderate consumption of alcohol can cause development problems in babies.

Abusing illicit drugs
Cocaine, phencyclidine and methamphetamine stimulate the central nervous system. They reduce the mothers appetite causing the blood vessels to constrict, make heart beat faster, blood pressure to rise. Drugs can also alter the functionality of the placenta by causing blood vessels to constrict and hence reduce supply of oxygen and nutrients to the fetus. This results in an underdeveloped baby and also hinders the growth of the fetus and can cause a condition called abruptio placentae (partial separation of the placenta from the uterus wall which results in bleeding). A drug like cocaine has a low molecular weight and is lipophilic hence it easily diffuses over the placenta. If the mother takes these drugs late in pregnancy the baby may suffer from neonatal abstinence syndrome where the baby experiences withdrawal symptoms like sleeplessness, irritability, diarrhea, tremors, sucking difficulties and muscle spasms. Drug abuse may also lead to (hypoglycemia) low blood sugar, breathing difficulties and intracranial hemorrhage. Inhalants like glue and paint contain an organic solvent toluene which causes premature births of babies with malformations.

Infections and diseases
The placenta cannot filter small disease carriers like viruses. Children can be born with diseases transmitted from the mother like malaria, mumps, syphilis and other venereal diseases. Infections such as sexually transmitted diseases like gonorrhea and chlamydia cause premature births. Rubella is a viral disease which when conducted within the first three months of pregnancy can result to giving birth to a premature baby with congenital problems like heart disease, cataracts, deafness, microcephaly and mental retardation. Toxemia is another condition that results to preterm babies who are smaller than average for their gestation age. Women with toxemia may go into convulsions or coma which causes the mother to strain and this is passed over to the fetus. Anoxia is also another condition that results into babies that are not well developed. This is because it causes the brain of the child not to receive enough oxygen and thus not develop properly. Toxoplasma results in premature births. It is a protozoan parasite which is able to cross the placenta. It results to growth retardation, neurological abnormalities, seizure and psychomotor retardation. Toxoplasma infection has also been linked with head and eye malfunctions.

Medication
Some medications have adverse effects during pregnancy and may cause the muscles of the uterus to contract forcefully and thus trigger preterm delivery. This forcefully contraction may also indirectly injure the fetus by reduction of its blood supply. Women are advised to consult a doctor before taking any drugs. Angiotensin-converting enzyme (ACE) inhibitors which are used to treat high blood pressure can cause growth restrictions and problems with infants kidney. Isotretinoin which is used to treat acne causes congenital abnormalities which include cleft palate, under development of the outer jaw, neural tube defects and abnormalities of the outer ear. Ergotamine and methysergide which are antimigraine drugs are used to set off migraine attacks but lead to premature labor. Anticoagulants are used to treat heart diseases and stroke. When taken during pregnancy the result in premature babies with facial malformations and mental retardation. There is also a high risk of uncontrolled bleeding.

Environmental chemical substances
Some chemical substances like mercury lead to premature births and have adverse effects on the baby. Mercury which is found in some types of fish is also associated with neurological cerebral palsy resembling, congenital abnormalities and mental retardation. Lead and cadmium impair the function of enzymes involved in production of energy and this leads to death of cells or impaired cell production and hence causes fetal growth restriction and neurological disorders. X-rays lead to problems with fetal development like spina bifida, cleft palate, blindness, abnormalities of the arms and legs or microcephaly. The type of condition that the baby is affected by depends on the dose of x-rays radiation and how old the pregnancy is. Chemotherapy which is used to treat cancer is linked with congenital disorders. Such a treatment should be delayed until birth to prevent pre-mature births and its associated abnormalities.

Caffeine
High caffeine intake may slightly cause pre-mature labor or aggravate other factors that cause preterm labor. Caffeine has been found to cross through the placenta to the baby. It can also lead to low birth weight. Recent research has shown that women who consumed more than five hundred milligrams of coffee a day gave birth to babies with faster heart and breathing rates. In the first few days of birth they spend more time awake. Although caffeine intake has negative implications on the birth of premature babies, it has been used for the past twenty five years to apnea of prematurity. Apnea is a condition in which babies who have been born prematurely stop breathing for fifteen to twenty seconds when they are sleeping.

Conclusion
A healthy lifestyle can go a long way toward preventing preterm labor and premature birth. To prevent premature births, a mother should ensure that she does not smoke, take drugs like cocaine, or consume alcohol and that she avoids exposure to environmental chemicals during pregnancy. Instead she should have a healthy diet, exercise regularly, have plenty of rest and seek early prenatal care. Premature births resulting from chronic medical conditions require regular care and frequent visits to the doctor so as to receive advice on the type of medication to use. Recently there have been teratogen information services which are available through genetic centers and in hospitals whose role is to give awareness on the known teratogens and the risks associated with them.

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