Obstetric ultrasound has become useful in the assessment of the cervix in women at risk for premature delivery. A short cervix preterm is undesirable: A cervical length of less than 25 mm at or before 24 weeks of gestational age is the most common definition of cervical incompetence.

Fetal fibronectin (fFN) has become an important biomarker—the presence of this glycoprotein in the cervical or vaginal secretions indicates that the border between the chorion and deciduas has been disrupted. A positive test indicates an increased risk of preterm birth, and a negative test has a high predictive value. It has been shown that only 1% of women in questionable cases of preterm labor delivered within the next week when the test was negative.

Obstetric ultrasonography can detect fetal abnormalities, detect multiple pregnancies, and improve gestational dating at 24 weeks. The resultant estimated gestational age and due date of the fetus are slightly more accurate than methods based on last menstrual period. Ultrasound is used to measure the nuchal fold in order to screen for Downs syndrome.

Pregnancy detection can be accomplished using one or more various pregnancy tests, which detect hormones generated by the newly formed placenta, serving as biomarkers of pregnancy. Blood and urine tests can detect pregnancy 12 days after implantation. Blood pregnancy tests are more sensitive than urine tests (giving fewer false negatives). Home pregnancy tests are urine tests, and normally detect a pregnancy 12 to 15 days after fertilization. A quantitative blood test can determine approximately the date the embryo was conceived because HCG doubles every 36 to 48 hours. A single test of progesterone levels can also help determine how likely a fetus will survive in those with a threatened miscarriage (bleeding in early pregnancy).

Some disorders and conditions can mean that pregnancy is considered high-risk (about 6-8% of pregnancies in the USA) and in extreme cases may be contraindicated. High-risk pregnancies are the main focus of doctors specialising in maternal-fetal medicine.

Serious pre-existing disorders which can reduce a woman's physical ability to survive pregnancy include a range of congenital defects (that is, conditions with which the woman herself was born, for example, those of the heart or , some of which are listed above) and diseases acquired at any time during the woman's life.

Some studies show that the probability of premature birth is roughly 1% higher for women who smoke during pregnancy going from around -1% to 1%.

A study by the Agency for Healthcare Research and Quality (AHRQ) found that of the 3.8 million births that occurred in the United States in 2011, approximately 6.1% (231,900) were diagnosed with low birth weight (<2,500 g). Approximately 49,300 newborns (1.3%) weighed less than 1,500 grams (VLBW). Infants born at low birth weight are at a higher risk for developing neonatal infection.

LBW is closely associated with fetal and Perinatal mortality and Morbidity, inhibited growth and cognitive development, and chronic diseases later in life. At the population level, the proportion of babies with a LBW is an indicator of a multifaceted public-health problem that includes long-term maternal malnutrition, ill health, hard work and poor health care in pregnancy. On an individual basis, LBW is an important predictor of newborn health and survival and is associated with higher risk of infant and childhood mortality.

Low birth weight constitutes as sixty to eighty percent of the infant mortality rate in developing countries. Infant mortality due to low birth weight is usually directly causal, stemming from other medical complications such as preterm birth, poor maternal nutritional status, lack of prenatal care, maternal sickness during pregnancy, and an unhygienic home environment. According to an analysis by University of Oregon, reduced brain volume in children is also tied to low birth-weight.

According to a study conducted in 2008 by the Pregnancy Risk Assessment Monitoring System (PRAMS) that interviewed women in 26 states in the United States, approximately 13% of women reported smoking during the last 3 months of pregnancy. Of women who smoked during the last 3 months of pregnancy, 52% reported smoking 5 or fewer cigarettes per day, 27% reported smoking 6 to 10 cigarettes per day, and 21% reported smoking 11 or more cigarettes per day.

In the United States, women whose pregnancies were unintended are 30% more likely to smoke during pregnancy than those whose pregnancies were intended.

Factors increasing the risk (to either the woman, the fetus/es, or both) of pregnancy complications beyond the normal level of risk may be present in a woman's medical profile either before she becomes pregnant or during the pregnancy. These pre-existing factors may relate to physical and/or mental health, and/or to social issues, or a combination.

Some common risk factors include:

- Age of either parent

- Adolescent parents

- Older parents

- Exposure to environmental toxins in pregnancy

- Exposure to recreational drugs in pregnancy:

- Ethanol during pregnancy can cause fetal alcohol syndrome and fetal alcohol spectrum disorder.

- Tobacco smoking and pregnancy, when combined, causes twice the risk of premature rupture of membranes, placental abruption and placenta previa. Also, it causes 30% higher odds of the baby being born prematurely.

- Prenatal cocaine exposure is associated with, for example, premature birth, birth defects and attention deficit disorder.

- Prenatal methamphetamine exposure can cause premature birth and congenital abnormalities. Other investigations have revealed short-term neonatal outcomes to include small deficits in infant neurobehavioral function and growth restriction when compared to control infants. Also, prenatal methamphetamine use is believed to have long-term effects in terms of brain development, which may last for many years.

- Cannabis in pregnancy is possibly associated with adverse effects on the child later in life.

- Exposure to Pharmaceutical drugs in pregnancy. Anti-depressants, for example, may increase risks of such outcomes as preterm delivery.

- Ionizing radiation

- Risks arising from previous pregnancies:

- Complications experienced during a previous pregnancy are more likely to recur.

- Many previous pregnancies. Women who have had five previous pregnancies face increased risks of very rapid labor and excessive bleeding after delivery.

- Multiple previous fetuses. Women who have had more than one fetus in a previous pregnancy face increased risk of mislocated placenta.

- Multiple pregnancy, that is, having more than one fetus in a single pregnancy.

- Social and socioeconomic factors. Generally speaking, unmarried women and those in lower socioeconomic groups experience an increased level of risk in pregnancy, due at least in part to lack of access to appropriate prenatal care.

- Unintended pregnancy. Unintended pregnancies preclude preconception care and delays prenatal care. They preclude other preventive care, may disrupt life plans and on average have worse health and psychological outcomes for the mother and, if birth occurs, the child.

- Height. Pregnancy in women whose height is less than 1.5 meters (5 feet) correlates with higher incidences of preterm birth and underweight babies. Also, these women are more likely to have a small pelvis, which can result in such complications during childbirth as shoulder dystocia.

- Weight

- Low weight: Women whose pre-pregnancy weight is less than 45.5 kilograms (100 pounds) are more likely to have underweight babies.

- Obese women are more likely to have very large babies, potentially increasing difficulties in childbirth. Obesity also increases the chances of developing gestational diabetes, high blood pressure, preeclampsia, experiencing postterm pregnancy and/or requiring a cesarean delivery.

- Intercurrent disease in pregnancy, that is, a disease and condition not necessarily directly caused by the pregnancy, such as diabetes mellitus in pregnancy, SLE in pregnancy or thyroid disease in pregnancy.

People infected with CMV develop antibodies to it, initially IgM later IgG indicating current infection and immunity respectively. If the virus is detected in the blood, saliva, urine or other body tissues, it means that the person has an active infection.

When infected with CMV, most women have no symptoms, but some may have symptoms resembling mononucleosis. Women who develop a mononucleosis-like illness during pregnancy should consult their medical provider.

The Centers for Disease Control and Prevention (CDC) does not recommend routine maternal screening for CMV infection during pregnancy because there is no test that can definitively rule out primary CMV infection during pregnancy. Women who are concerned about CMV infection during pregnancy should practice CMV prevention measures.Considering that the CMV virus is present in saliva, urine, tears, blood, mucus, and other bodily fluids, frequent hand washing with soap and water is important after contact with diapers or oral secretions, especially with a child who is in daycare or interacting with other young children on a regular basis.

A diagnosis of congenital CMV infection can be made if the virus is found in an infant's urine, saliva, blood, or other body tissues during the first week after birth. Antibody tests cannot be used to diagnose congenital CMV; a diagnosis can only be made if the virus is detected during the first week of life. Congenital CMV cannot be diagnosed if the infant is tested more than one week after birth.

Visually healthy infants are not routinely tested for CMV infection although only 10–20% will show signs of infection at birth though up to 80% may go onto show signs of prenatal infection in later life. If a pregnant woman finds out that she has become infected with CMV for the first time during her pregnancy, she should have her infant tested for CMV as soon as possible after birth.

Treatment of infants suffering birth asphyxia by lowering the core body temperature is now known to be an effective therapy to reduce mortality and improve neurological outcome in survivors, and hypothermia therapy for neonatal encephalopathy begun within 6 hours of birth significantly increases the chance of normal survival in affected infants.

There has long been a debate over whether newborn infants with birth asphyxia should be resuscitated with 100% oxygen or normal air. It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia. Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen.

IH/BA is also a causitive factor in cardiac and circulatory birth defects the sixth most expensive condition, as well as premature birth and low birth weight the second most expensive and it is one of the contributing factors to infant respiratory distress syndrome (RDS) also known as hyaline membrane disease, the most expensive medical condition to treat and the number one cause of infant mortality.

Recommendations for pregnant women with regard to CMV infection:

- Throughout the pregnancy, practice good personal hygiene, especially handwashing with soap and water, after contact with diapers or oral secretions (particularly with a child who is in day care). Sharing of food, eating and drinking utensils, and contact with toddlers' saliva should be avoided.

- Women who develop a mononucleosis-like illness during pregnancy should be evaluated for CMV infection and counseled about the possible risks to the unborn child.

- Laboratory testing for antibody to CMV can be performed to determine if a woman has already had CMV infection.

- Recovery of CMV from the cervix or urine of women at or before the time of delivery does not warrant a cesarean section.

- The demonstrated benefits of breast-feeding outweigh the minimal risk of acquiring CMV from the breast-feeding mother.

- There is no need to either screen for CMV or exclude CMV-excreting children from schools or institutions because the virus is frequently found in many healthy children and adults.

Treatment with hyperimmune globulin in mothers with primary CMV infection has been shown to be effective in preventing congenital disease in several studies. One study did not show significant decrease in the risk of congenital cytomegalovirus infection.

AOP is usually treated by blood transfusion but the indications for this are still unclear. Blood transfusions have the risk of incompatibility and transfusion reactions as well as viral infections. Also, blood transfusions are costly and add to parental anxiety. The best treatment in prevention is minimizing the amount of blood drawn from the infant. It is found that since blood loss attributable to laboratory testing is the primary cause of anemia among preterm infants during the first weeks of life, we quantified blood lost attributable to phlebotomy overdraw, something that might be avoided. A study was done to see when and if overdraw was a problem. They recorded all of the data that could be of influence such as the test performed, the blood collection container used, the infants location (neonatal intensive care unit (NICU) and intermediate intensive care unit), the infant’s weight sampling and the phlebotomist’s level of experience, work shift, and clinical role. Infants were classified by weight into 3 groups: 2 kg. The volume of blood removed was calculated by subtracting the weight of the empty collection container from that of the container filled with blood. They found that the mean volume of blood drawn for the 578 tests exceeded that requested by the hospital laboratory by 19.0% ± 1.8% per test. The main factors of overdraw was: collection in blood containers without fill-lines, lighter weight infants and critically ill infants being cared for in the NICU.

Neonatal sepsis of the newborn is an infection that has spread through the entire body. The inflammatory response to this systematic infection can be as serious as the infection itself. In infants that weigh under 1500 g, sepsis is the most common cause of death. Three to four percent of infants per 1000 births contract sepsis. The mortality rate from sepsis is near 25%. Infected sepsis in an infant can be identified by culturing the blood and spinal fluid and if suspected, intravenous antibiotics are usually started. Lumbar puncture is controversial because in some cases it has found not to be necessary while concurrently, without it estimates of missing up to one third of infants with meningitis is predicted.

Recombinant EPO (r-EPO) may be given to premature infants to stimulate red blood cell production. Brown and Keith (1999) studied two groups of 40 very low birth weight (VLBW) infants to compare the erythropoietic response between two and five times a week dosages of recombinant human erythropoietin (r-EPO) using the same dose. They established that more frequent dosing of the same weekly amount of r-EPO generated a significant and continuous increase in Hb in VLBW infants. The infants that received five dosages had 219,857 mm³ while infants that received two dosages only had 173,361 mm³. However, the response to r-EPO typically takes up to two weeks and the higher dosages lead to higher Hb. Brown and Keith (1999) study also showed responses between two dosage schedules (two times a week and five times a week). Infants were recruited for gestational age—age since conception—≤27 weeks and 28 to 30 weeks and then randomized into the two groups, each totaling 500 U/kg a week. Brown and Keith found that after two weeks of r-EPO administration, Hb counts had increased and leveled off; the infants who received r-EPO five times a week had significantly higher Hb counts. This was present at four weeks for all infants ≤30 weeks gestation and at 8 weeks for infants ≤27 weeks gestation.

To date, studies of r-EPO use in premature infants have had mixed results. Ohls et al. examined the use of early r-EPO plus iron and found no short-term benefits in two groups of infants (172 infants less than 1000 g and 118 infants 1000–1250 g). All r-EPO treated infants received 400 U/g three times a week until they reached 35 weeks gestational age. The use of r-EPO did not decrease the average number of transfusions in the infants born at less than 1000 g, or the percentage of infants in the 1000 to 1250 group. A multi-center European trial studied early versus late r-EPO in 219 infants with birth weights between 500 and 999 g. An r-EPO close of 750 U/kg/week was given to infants in both the early (1–9 weeks) and late (4–10 weeks) groups. The two r-EPO groups were compared to a control group who did not receive r-EPO. Infants in all three groups received 3 to 9 mg/kg of enteral iron. These investigators reported a slight decrease in transfusion and donor exposures in the early r-EPO group (1–9 weeks): 13% early, 11% late and 4% control group. It is likely that only a carefully selected subpopulation of infants may benefit from its use. Contrary to what just said, Bain and Blackburn (2004) also state in another study the use of r-EPO does not appear to have a significant effect on reducing the numbers of early transfusions in most infants, but may be useful to reduce numbers of late transfusion in extremely low-birth-weight infants. A British task force to establish transfusion guidelines for neonates and young children and to help try to explain this confusion recently concluded that “the optimal dose, timing, and nutritional support required during EPO treatment has yet to be defined and currently the routine use of EPO in this patient population is not recommended as similar reduction in blood use can probably be achieved with appropriate transfusion protocols.”

Previa can be confirmed with an ultrasound. Transvaginal ultrasound has superior accuracy as compared to transabdominal one, thus allowing measurement of distance between placenta and cervical os. This has rendered traditional classification of placenta previa obsolete.

False positives may be due to following reasons:

- Overfilled bladder compressing lower uterine segment

- Myometrial contraction simulating placental tissue in abnormally low location

- Early pregnancy low position, which in third trimester may be entirely normal due to differential growth of the uterus.

In such cases, repeat scanning is done after an interval of 15–30 minutes.

In parts of the world where ultrasound is unavailable, it is not uncommon to confirm the diagnosis with an examination in the surgical theatre. The proper timing of an examination in theatre is important. If the woman is not bleeding severely she can be managed non-operatively until the 36th week. By this time the baby's chance of survival is as good as at full term.

History may reveal antepartum hemorrhage. Abdominal examination usually finds the uterus non-tender, soft and relaxed. Leopold's Maneuvers may find the fetus in an oblique or breech position or lying transverse as a result of the abnormal position of the placenta. Malpresentation is found in about 35% cases. Vaginal examination is avoided in known cases of placenta previa.

U.S. Code of Federal Regulations requires that certain drugs and biological products must be labelled very specifically with respect to their effects on pregnant populations, including a definition of a "pregnancy category." These rules are enforced by the Food and Drug Administration (FDA). The FDA does not regulate labelling for all hazardous and non-hazardous substances and some potentially hazardous substances are not assigned a pregnancy category.

Australia’s categorisations system takes into account the birth defects, the effects around the birth or when the mother gives birth, and problems that will arise later in the child's life caused from the drug taken. The system places them into a category of their severity that the drug could cause to the infant when it crosses the placenta(Australian Government, 2014).

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.

The effects of high blood pressure during pregnancy vary depending on the disorder and other factors. Preeclampsia does not in general increase a woman's risk for developing chronic hypertension or other heart-related problems. Women with normal blood pressure who develop preeclampsia after the 20th week of their first pregnancy, short-term complications--including increased blood pressure--usually go away within about 6 weeks after delivery.

Some women, however, may be more likely to develop high blood pressure or other heart disease later in life. More research is needed to determine the long-term health effects of hypertensive disorders in pregnancy and to develop better methods for identifying, diagnosing, and treating women at risk for these conditions.

Even though high blood pressure and related disorders during pregnancy can be serious, most women with high blood pressure and those who develop preeclampsia have successful pregnancies. Obtaining early and regular prenatal care is the most important thing you can do for you and your baby.

A large investigation into diphtheria-tetanus-pertussis vaccination and potential SIDS association by Berlin School of Public Health, Charité – Universitätsmedizin Berlin concluded: "Increased DTP immunisation coverage is associated with decreased SIDS mortality. Current recommendations on timely DTP immunisation should be emphasised to prevent not only specific infectious diseases but also potentially SIDS."

Many other studies have also reached conclusions that vaccinations reduce the risk of SIDS. Studies generally show that SIDS risk is approximately halved by vaccinations.

Families who are impacted by SIDS should be offered emotional support and grief counseling. The experience and manifestation of grief at the loss of an infant are impacted by cultural and individual differences.

Vaccinating the majority of the population is effective at preventing congenital rubella syndrome.