Tobacco smoking and pregnancy is related to many effects on health and reproduction, in addition to the general health effects of tobacco. A number of studies have shown that tobacco use is a significant factor in miscarriages among pregnant smokers, and that it contributes to a number of other threats to the health of the fetus.

Ideally, women should not smoke before, during or after pregnancy. If this is not the case, however, the daily number of cigarettes can be reduced to minimize the risks for both the mother and child. This is particularly important for women in developing countries where breastfeeding is essential for the child's overall nutritional status.

Alcohol in pregnancy is the use of alcohol (also known formally as ethanol) during gestation. This also includes the time period between conception and awareness of the pregnancy. Alcohol use not only can result in Fetal Alcohol Spectrum Disorder (FASD), but it can result in one or many other disorders and conditions. Not all women who consume alcohol during pregnancy will have a baby with all of the features and characteristics of FASP. Alcohol use during pregnancy also can cause spontaneous abortion, stillbirth, low birthweight, and prematurity. Not all infants exposed to alcohol in utero will have defects related to the alcohol consumption. Alcohol use during pregnancy can also result in the inability to care for an infant after the birth if the drinking continues. The use of alcohol during pregnancy is associated with domestic violence and potential harm to the infant.

Drug use during pregnancy can have temporary or permanent effects on the fetus. Any drug that acts during embryonic or fetal development to produce a permanent alteration of form or function is known as a teratogen. Drugs may refer to both pharmaceutical drug and recreational drugs.

Hyperemesis gravidarum is the presence of severe and persistent vomiting, causing dehydration and weight loss. It is more severe than the more common morning sickness and is estimated to affect 0.5–2.0% of pregnant women.

Gestational diabetes is when a woman without diabetes develops high blood sugar levels during pregnancy.

Different body systems in the infant grow, mature and develop at specific times during gestation. The consumption of alcohol during one or more of these developmental stages may only result in one or few conditions.

From conception and to the third week, the most susceptible systems and organs are the brain, spinal cord, and heart. Though these body systems complete their development later in the pregnancy, the effects of alcohol consumption early in the pregnancy can result in defects to these systems and organs.

During the fourth week of gestation, the limbs are being formed and it is at this point that alcohol can effect the development of arms, legs, fingers and toes. The eyes and ears also form during the fourth week and are more susceptible to the effects of alcohol.

By the sixth week of gestation, the teeth and palate are forming and alcohol consumption at this time will affect these structures.

By the 20th week of gestation the formation of organs and organ systems is well-developed. The infant is still susceptible to the damaging effects of alcohol.

The baby’s brain, body, and organs are developing throughout pregnancy and can be affected by exposure to alcohol at any time. Because every pregnancy is different, drinking alcohol may hurt one baby more than another. A child that has been affected by alcohol before birth may be appear 'normal' at birth. Intellectual disabilities may not appear until the child begins school.

It is recommended for women planning pregnancy to stop smoking. It is important to examine these effects because smoking before, during and after pregnancy is not an unusual behavior among the general population and can have detrimental health impacts, especially among both mother and child as a result. In 2011, approximately 10% of pregnant women in data collected from 24 states reported smoking during the last three months of their pregnancy.

Withdrawal from marijuana can initiate a preterm birth and meconium staining.

An infant born addicted to amphetamines is more likely to be born prematurely. It may also be small for gestational age. It may show signs of respiratory distress, infection, exaggerated startle reflex, sleep pattern disturbances. After the infant is born it may have poor weight gain, frequent infections, developmental delays and emotional problems.

Slowed growth is well documented in fetuses, but it is not as clear whether older children remain smaller or catch up to their peers. Some studies show that growth remains slowed for as many as ten years. PCE may also interfere with the way the motor system matures. Motor effects that have been documented include poorer reflexes and quality of movement in infants. PCE may have an effect on the neuroendocrine system, but more study is needed to determine whether it does and what the effects are.

A review of the literature reported that cocaine use causes congenital defects between 15 and 20% of the time; however another large-scale study found no difference in rates of birth anomalies in PCE and non-PCE infants. It has been suggested that some birth defects could be due to cocaine's disruption of blood vessel growth.

Most PCE-related congenital defects are found in the brain, heart, genitourinary tract, arms and legs.

Cocaine use by pregnant mothers may directly or indirectly contribute to defects in the formation of the circulatory system and is associated with abnormalities in development of the aorta. Heart malformations can include a missing ventricle and defects with the septum of the heart, and can result in potentially deadly congestive heart failure. Genital malformations occur at a higher-than-normal rate with PCE.

The liver and lungs are also at higher risk for abnormalities. Cloverleaf skull, a congenital malformation in which the skull has three lobes, the brain is deformed, and hydrocephalus occurs, is also associated with PCE. Like birth defects, small head size, and stroke are risks in PCE.

The apprehension is not necessarily data driven and is a cautionary response to the lack of clinical studies in pregnant women. The indication is a trade-off between the adverse effects of the drug, the risks associated with intercurrent diseases and pregnancy complications, and the efficiency of the drug to prevent or ameliorate such risks. In some cases, the use of drugs in pregnancy carries benefits that outweigh the risks. For example, high fever is harmful for the fetus in the early months, thus the use of paracetamol (acetaminophen) is generally associated with lower risk than the fever itself. Similarly, diabetes mellitus during pregnancy may need intensive therapy with insulin to prevent complications to mother and baby. Pain management for the mother is another important area where an evaluation of the benefits and risks is needed. NSAIDs such as Ibuprofen and Naproxen are probably safe for use for a short period of time, 48–72 hours, once the mother has reached the second trimester. If taking aspirin for pain management the mother should never take a dose higher than 100 mg.

Pregnancy over age 50 has, over recent years, become more possible for women, due to recent advances in assisted reproductive technology, in particular egg donation. Typically, a woman's fecundity ends with menopause, which by definition is 12 consecutive months without having had any menstrual flow at all. During perimenopause, the menstrual cycle and the periods become irregular and eventually stop altogether, but even when periods are still regular, the egg quality of women in their forties is lower than in younger women, making the likelihood of conceiving a healthy baby also reduced, particularly after age 42. It is important to note, that the female biological clock can vary greatly from woman to woman. A woman's individual level of fertility can be tested through a variety of methods.

Men also experience a decline in fertility as they age, for example, the average time to pregnancy if a man is under 25 is just over 4.5 months but nearly two years if a man is over 40 (if the woman is under 25). The risk of genetic defects is greatly increased due to the paternal age effect. Children with fathers aged 40 or older are more than five times as likely to have an autism spectrum disorder than children fathered by men aged under 30. Researchers estimate that compared to a male fathering a child in his early 20's - there is double the chance of the child getting schizophrenia when the father is age 40, and triple the risk of schizophrenia when the father is age 50 (though, for most people this means the risk goes from approximately 1 in 121 when a man is 29, to 1 in 47 when a man is age 50 to 54). Men's fertility declines throughout the lifespan, with the volume of a man’s semen and sperm motility (the ability of sperm to move towards an egg) decrease continually between the ages of 20 and 80. The risk of dwarfism and miscarriage also increases as men age

In the United States, between 1997 and 1999, 539 births were reported among mothers over age 50 (four per 100,000 births), with 194 being over 55.

The oldest mother to date to conceive, was 71 years, and the youngest mother, 5 years old. According to statistics from the Human Fertilisation and Embryology Authority, in the UK more than 20 babies are born to women over age 50 per year through in-vitro fertilization with the use of donor oocytes (eggs).

Maria del Carmen Bousada de Lara is the oldest verified mother; she was aged 66 years 358 days when she gave birth to twins; she was 130 days older than Adriana Iliescu, who gave birth in 2005 to a baby girl. In both cases the children were conceived through IVF with donor eggs. The oldest verified mother to conceive naturally (listed currently in the Guinness Records) is Dawn Brooke (UK); she conceived a son at the age of 59 years in 1997 while taking oestrogen.

Prenatal cocaine exposure (PCE), theorized in the 1970s, occurs when a pregnant woman uses cocaine and thereby exposes her fetus to the drug. "Crack baby" was a term coined to describe children who were exposed to crack (freebase cocaine in smokable form) as fetuses; the concept of the crack baby emerged in the US during the 1980s and 1990s in the midst of a crack epidemic. Other terms are "cocaine baby" and "crack kid". Early studies reported that people who had been exposed to crack in utero would be severely emotionally, mentally, and physically disabled; this belief became common in the scientific and lay communities. Fears were widespread that a generation of crack babies were going to put severe strain on society and social services as they grew up. Later studies failed to substantiate the findings of earlier ones that PCE has severe disabling consequences; these earlier studies had been methodologically flawed (e.g. with small sample sizes and confounding factors). Scientists have come to understand that the findings of the early studies were vastly overstated and that most people who were exposed to cocaine "in utero" do not have disabilities.

No specific disorders or conditions have been found to result for people whose mothers used cocaine while pregnant. Studies focusing on children of six years and younger have not shown any direct, long-term effects of PCE on language, growth, or development as measured by test scores. PCE also appears to have little effect on infant growth.

However, PCE is associated with premature birth, birth defects, attention deficit hyperactivity disorder, and other conditions. The effects of cocaine on a fetus are thought to be similar to those of tobacco and less severe than those of alcohol. No scientific evidence has shown a difference in harm to a fetus between crack and powder cocaine.

PCE is very difficult to study because it very rarely occurs in isolation: usually it coexists with a variety of other factors, which may confound a study's results. Thus, studies have failed to clearly show that PCE has negative cognitive effects, partly because such effects may be due to concurrent factors. Pregnant mothers who use cocaine often use other drugs in addition, or they may be malnourished and lacking in medical care. Children in households where cocaine is abused are at risk of violence and neglect, and those in foster care may experience problems due to unstable family situations. Factors such as poverty that are frequently associated with PCE have a much stronger influence on children's intellectual and academic abilities than does exposure to cocaine in isolation. Thus researchers have had difficulty in determining which effects result from PCE and which result from other factors in the children's histories.

Generally it is preferable to describe specific signs in lieu of declaring "fetal distress" that include:

- Decreased movement felt by the mother

- Meconium in the amniotic fluid ("meconium stained fluid")

- Non-reassuring patterns seen on cardiotocography:

- increased or decreased fetal heart rate (tachycardia and bradycardia), especially during and after a contraction

- decreased variability in the fetal heart rate

- late decelerations

- Biochemical signs, assessed by collecting a small sample of baby's blood from a scalp prick through the open cervix in labor

- fetal metabolic acidosis

- elevated fetal blood lactate levels (from fetal scalp blood testing) indicating the baby has a lactic acidosis

Some of these signs are more reliable predictors of fetal compromise than others. For example, cardiotocography can give high false positive rates, even when interpreted by highly experienced medical personnel. Metabolic acidosis is a more reliable predictor, but is not always available.

There are many causes of "fetal distress" including:

- Breathing problems

- Abnormal position and presentation of the fetus

- Multiple births

- Shoulder dystocia

- Umbilical cord prolapse

- Nuchal cord

- Placental abruption

- Premature closure of the fetal ductus arteriosus

- Uterine rupture

- Intrahepatic cholestasis of pregnancy, a liver disorder during pregnancy

In terms of FASD, growth deficiency is defined as significantly below average height, weight or both due to prenatal alcohol exposure, and can be assessed at any point in the lifespan. Growth measurements must be adjusted for parental height, gestational age (for a premature infant), and other postnatal insults (e.g., poor nutrition), although birth height and weight are the preferred measurements. Deficiencies are documented when height or weight falls at or below the 10th percentile of standardized growth charts appropriate to the population.

Criteria for FASD are least specific in the IOM diagnostic system ("low birth weight..., decelerating weight not due to nutrition..., [or] disproportional low weight to height" p. 4 of executive summary), while the CDC and Canadian guidelines use the 10th percentile as a cut-off to determine growth deficiency. The "4-Digit Diagnostic Code" allows for mid-range gradations in growth deficiency (between the 3rd and 10th percentiles) and severe growth deficiency at or below the 3rd percentile. Growth deficiency (at severe, moderate, or mild levels) contributes to diagnoses of FAS and pFAS, but not ARND or static encephalopathy.

Growth deficiency is ranked as follows by the "4-Digit Diagnostic Code":

- Severe: Height and weight at or below the 3rd percentile.

- Moderate: Either height or weight at or below the 3rd percentile, but not both.

- Mild: Either height or weight or both between the 3rd and 10th percentiles.

- None: Height and weight both above the 10th percentile.

In the initial studies that discovered FAS, growth deficiency was a requirement for inclusion in the studies; thus, all the original people with FAS had growth deficiency as an artifact of sampling characteristics used to establish criteria for the syndrome. That is, growth deficiency is a key feature of FASD because growth deficiency was a criterion for inclusion in the study that defined FAS. This suggests growth deficiency may be less critical for understanding the disabilities of FASD than the neurobehavioral sequelae to the brain damage.

The key of FASD can vary between individuals exposed to alcohol during pregnancy. While consensus exists for the definition and diagnosis of FAS, minor variations among the systems lead to differences in definitions and diagnostic cut-off criteria for other diagnoses across the FASD continuum. The central nervous system damage criteria particularly lack clear consensus. A working knowledge of the key features is helpful in understanding FASD diagnoses and conditions, and each is reviewed with attention to similarities and differences across the four diagnostic systems. More than 400 problems, however, can occur with FASD.

Developmental toxicity is any structural or functional alteration, reversible or irreversible, which interferes with homeostasis, normal growth, differentiation, development or behavior, and which is caused by environmental insult (including drugs, lifestyle factors such as alcohol, diet, and environmental toxic chemicals or physical factors). It is the study of adverse effects on the development of the organism resulting from exposure to toxic agents before conception (either parent), during prenatal development, or post-natally until puberty. The substance that causes developmental toxicity from embryonic stage to birth is called teratogens. The effect of the developmental toxicants depends on the type of substance, dose and duration and time of exposure.

Certain Pathogens are also included since the toxins they secrete are known to cause adverse effects on the development of the organism when the mother or fetus is infected. Developmental toxicology is a science studying adverse developmental outcomes. This term has widely replaced the early term for the study of primarily structural congenital abnormalities, teratology, to enable inclusion of a more diverse spectrum of congenital disorders. Typical factors causing developmental toxicity are radiation, infections (e.g. rubella), maternal metabolic imbalances (e.g. alcoholism, diabetes, folic acid deficiency), drugs (e.g. anticancer drugs, tetracyclines, many hormones, thalidomide), and environmental chemicals (e.g. mercury, lead, dioxins, PBDEs, HBCD, tobacco smoke). The first-trimester exposure is considered the most potential for developmental toxicity.

Once fertilization has taken place, the toxicants in the environment can pass through the mother to the developing embryo or fetus across the placental barrier. The fetus is at greatest risk during the first 14th to 60th day of the pregnancy when the major organs are being formed. However, depending on the type of toxicant and amount of exposure, a fetus can be exposed toxicant at any time during pregnancy. For example, exposure to a particular toxicant at one time in the pregnancy may result in organ damage and at another time in the pregnancy could cause death of the fetus and miscarriage. There are a number of chemicals, biological agents (such as bacteria and viruses), and physical agents (such as radiation) used in a variety of workplaces that are known to cause developmental disorders. Developmental disorders can include a wide range of physical abnormalities, such as bone or organ deformities, or behavioral and learning problems, such as a mental retardation. Exposures to some chemicals during pregnancy can lead to the development of cancer later in the life of the child and are called transgenerational carcinogens. Exposure to toxicants during the second and the third trimester of a pregnancy can lead to slow fetal grown and result in low birth weight.

Tobacco use has predominantly negative effects on human health and concern about health effects of tobacco has a long history. Research has focused primarily on cigarette tobacco smoking. In 1950, Richard Doll published research in the "British Medical Journal" showing a close link between smoking and lung cancer. Four years later, in 1954, the British Doctors Study, a study of some 40,000 doctors over 20 years, confirmed the suggestion, based on which the government issued advice that smoking and lung cancer rates were related.

Tobacco smoke contains more than fifty chemicals that cause cancer. Tobacco also contains nicotine, which is a highly addictive psychoactive drug. When tobacco is smoked, nicotine causes physical and psychological dependency. Cigarettes sold in underdeveloped countries tend to have higher tar content, and are less likely to be filtered, potentially increasing vulnerability to tobacco smoking related disease in these regions.

Tobacco use is the single greatest cause of preventable death globally. As many as half of people who use tobacco die from the results of this use. The World Health Organization (WHO) estimates that each year tobacco causes about 6 million deaths (about 10% of all deaths) with 600,000 of these occurring in non smokers due to second hand smoke. In the 20th century tobacco is estimated to have caused 100 million deaths. Similarly, the United States Centers for Disease Control and Prevention describes tobacco use as "the single most important preventable risk to human health in developed countries and an important cause of premature death worldwide."

Tobacco use leads most commonly to diseases affecting the heart, liver and lungs. Smoking is a major risk factor for heart attacks, strokes, chronic obstructive pulmonary disease (COPD) (including emphysema and chronic bronchitis), and cancer (particularly lung cancer, cancers of the larynx and mouth, and pancreatic cancer). It also causes peripheral vascular disease and hypertension. The effects depend on the number of years that a person smokes and on how much the person smokes. Starting smoking earlier in life and smoking cigarettes higher in tar increases the risk of these diseases. Also, environmental tobacco smoke, or secondhand smoke, has been shown to cause adverse health effects in people of all ages. Tobacco use is a significant factor in miscarriages among pregnant smokers, and it contributes to a number of other health problems of the fetus such as premature birth, low birth weight, and increases by 1.4 to 3 times the chance of sudden infant death syndrome (SIDS). Incidence of erectile dysfunction is approximately 85 percent higher in male smokers compared to non-smokers.

Several countries have taken measures to control the consumption of tobacco with usage and sales restrictions as well as warning messages printed on packaging. Additionally, smoke-free laws that ban smoking in public places such as workplaces, theaters, and bars and restaurants reduce exposure to secondhand smoke and help some people who smoke to quit, without negative economic effects on restaurants or bars. Tobacco taxes that increase the price is also effective, especially in developing countries.

The risk of pregnancy complications increases as the mother's age increases. Risks associated with childbearing over the age of 50 include an increased incidence of gestational diabetes, hypertension, delivery by caesarean section, miscarriage, preeclampsia, and placenta previa. In comparison to mothers between 20 and 29 years of age, mothers over 50 are at almost three times the risk of low birth weight, premature birth, and extremely premature birth; their risk of extremely low birth weight, small size for gestational age, and fetal mortality was almost double.

Fetal alcohol spectrum disorders (FASD) is a term that constitutes the set of conditions that can occur in a person whose mother drank alcohol during the course of pregnancy. These effects can include physical and cognitive problems. FASD patient usually has a combination of these problems. Extent of effect depends on exposure frequency, dose and rate of ethanol elimination from amniotic fluid. FAS disrupts normal development of the fetus, which may cause certain developmental stages to be delayed, skipped, or immaturely developed. Since alcohol elimination is slow in a fetus than in an adult and the fact that they do not have a developed liver to metabolize the alcohol, alcohol levels tend to remain high and stay in the fetus longer. Birth defects associated with prenatal exposure to alcohol can occur in the first three to eight weeks of pregnancy before a woman even knows that she is pregnant.

In most cases Ballantyne syndrome causes fetal or neonatal death and in contrast, maternal involvement is limited at the most to preeclampsia.

Green Tobacco Sickness (GTS) is a type of nicotine poisoning caused by the transdermal absorption of nicotine from the surface of wet tobacco plants. Tobacco harvesters, whose clothing becomes saturated from tobacco wet with rain or morning dew, are at high risk of developing GTS. Workers can avoid getting this sickness by waiting to harvest until the tobacco leaves are dry, or by wearing a rain suit. Wet clothing that has come in contact with tobacco leaves should be removed immediately and the skin washed with warm soapy water.

Nicotine from other sources, including nicotine gum, a nicotine patch or electronic cigarette, or other tobacco products like cigarettes or smokeless tobacco, appears to reduce the risk of GTS due to the body adapting to the intake of nicotine.

Symptoms of GTS include nausea, vomiting, headache, dizziness, and severe weakness. These symptoms may be accompanied by fluctuations in blood pressure or heart rate. Abdominal cramping, chills, increased sweating, salivation and difficulty breathing are also common. The illness will resolve on its own within one to two days, but symptoms may be so severe as to require emergency medical treatment.

Worldwide there are an estimated 33 million tobacco farm workers, with a substantial proportion living in developing countries. A recent international review reported that between 8-89% of tobacco harvesters may be affected in the course of a season (this wide variation probably being due to differences between study methodologies as well as a range of working conditions). The long-term health outcomes for individuals exposed to nicotine transdermally for extended periods of time are not known.

Nicotine dependence, or tobacco use disorder, is a state of dependence upon nicotine. There are different ways of measuring nicotine dependence. Some nicotine dependence assessments focus on key physical dependence outcomes like the development of tolerance which allows people to smoke heavily. Other assessments ask about psychosocial outcomes or underlying mechanisms of dependence. These different assessments either characterize dependence as a continuous construct or use cut-offs to diagnose whether or not a person is dependent.

Nicotine dependence is especially a concern among some populations such as those with co-occurring mental illness. There are evidence-based nicotine dependence treatments that include both medication and psychosocial interventions that can significantly increase a smoker’s chances of quitting successfully.

The problem of distinguishing (or not) between Ballantyne syndrome and preeclampsia is reflected in the diversity of terminology used and in the debate that surrounds the subject. It seems much more likely that an etiology of severe fetal hydrops may cause Ballantyne syndrome when the fetal status greatly worsens and that the syndrome is only a manifestation of the extreme severity of the fetus-placental pathology. Platelet count, aspartate transaminase, alanine transaminase, and haptoglobin are usually unaffected and may be used to distinguish mirror syndrome from HELLP syndrome.