There have been many assessments of tests aimed at predicting pre-eclampsia, though no single biomarker is likely to be sufficiently predictive of the disorder. Predictive tests that have been assessed include those related to placental perfusion, vascular resistance, kidney dysfunction, endothelial dysfunction, and oxidative stress. Examples of notable tests include:

- Doppler ultrasonography of the uterine arteries to investigate for signs of inadequate placental perfusion. This test has a high negative predictive value among those individuals with a history of prior pre-eclampsia.

- Elevations in serum uric acid (hyperuricemia) is used by some to "define" pre-eclampsia, though it has been found to be a poor predictor of the disorder. Elevated levels in the blood (hyperuricemia) are likely due to reduced uric acid clearance secondary to impaired kidney function.

- Angiogenic proteins such as vascular endothelial growth factor (VEGF) and placental growth factor (PIGF) and anti-angiogenic proteins such as soluble fms-like tyrosine kinase-1 (sFlt-1) have shown promise for potential clinical use in diagnosing pre-eclampsia, though evidence is sufficient to recommend a clinical use for these markers.

- Recent studies have shown that looking for podocytes (specialized cells of the kidney) in the urine has the potential to aid in the prediction of preeclampsia. Studies have demonstrated that finding podocytes in the urine may serve as an early marker of and diagnostic test for preeclampsia.

Pre-eclampsia can mimic and be confused with many other diseases, including chronic hypertension, chronic renal disease, primary seizure disorders, gallbladder and pancreatic disease, immune or thrombotic thrombocytopenic purpura, antiphospholipid syndrome and hemolytic-uremic syndrome. It must be considered a possibility in any pregnant woman beyond 20 weeks of gestation. It is particularly difficult to diagnose when preexisting disease such as hypertension is present. Women with acute fatty liver of pregnancy may also present with elevated blood pressure and protein in the urine, but differ by the extent of liver damage. Other disorders that can cause high blood pressure include thyrotoxicosis, pheochromocytoma, and drug misuse.

Convulsions during pregnancy that are unrelated to pre-eclampsia need to be distinguished from eclampsia. Such disorders include seizure disorders as well as brain tumor, aneurysm of the brain, and medication- or drug-related seizures. Usually the presence of the signs of severe pre-eclampsia precede and accompany eclampsia, facilitating the diagnosis.

Another core feature of pre-eclampsia is proteinuria, which is the presence of excess protein in the urine. To determine if proteinuria is present, the urine can be collected and tested for protein; if there is 0.3 grams of protein or more in the urine of a pregnant woman collected over 24 hours, this is one of the diagnostic criteria for pre-eclampsia and raises the suspicion that a seizure is due to eclampsia.

In cases of severe eclampsia or pre-eclampsia, the level of platelets in the blood can be low in a condition termed thrombocytopenia. A complete blood count, or CBC, is a test of the blood that can be performed to check platelet levels.

Other investigations include: renal function test (RFT), liver function tests (LFT), coagulation screen, 24-hour urine creatinine, and fetal/placental ultrasound.

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.

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.

In general, the indications for anticoagulation during pregnancy are the same as the general population. This includes (but is not limited to) a recent history of deep venous thrombosis (DVT) or pulmonary embolism, a metallic prosthetic heart valve, and atrial fibrillation in the setting of structural heart disease.

In addition to these indications, anticoagulation may be of benefit in individuals with lupus erythematosus, individuals who have a history of DVT or PE associated with a previous pregnancy, and even with individuals with a history of coagulation factor deficiencies and DVT not associated with a previous pregnancy.

In pregnant women with a history of recurrent miscarriage, anticoagulation seems to increase the live birth rate among those with antiphospholipid syndrome and perhaps those with congenital thrombophilia but not in those with unexplained recurrent miscarriage.

If a small amount of bleeding is seen in early pregnancy a physician may request:

- A quantitative human chorionic gonadotropin (hCG) blood test to confirm the pregnancy or assist in diagnosing a potential miscarriage

- Transvaginal pelvic ultrasonography to confirm that the pregnancy is not outside of the uterus

- Blood type and Rh test to rule out hemolytic disease of the newborn

For bleeding seen in later pregnancy tests may include:

- Complete blood count (CBC) and blood type and screen

- Ultrasound to determine placental location

- Kleihauer-Betke (KB) test especially if there was maternal trauma

Blood pressure control can be accomplished before pregnancy. Medications can control blood pressure. Certain medications may not be ideal for blood pressure control during pregnancy such as angiotensin-converting enzyme (ACE) inhibitors and Angiotensin II (AII) receptor antagonists. Controlling weight gain during pregnancy can help reduce the risk of hypertension during 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.

The PNMR refers to the number of perinatal deaths per 1,000 total births. It is usually reported on an annual basis. It is a major marker to assess the quality of health care delivery. Comparisons between different rates may be hampered by varying definitions, registration bias, and differences in the underlying risks of the populations.

PNMRs vary widely and may be below 10 for certain developed countries and more than 10 times higher in developing countries . The WHO has not published contemporary data.

Bed rest has not been found to improve outcomes and therefore is not typically recommended.

Mothers whose fetus is diagnosed with intrauterine growth restriction by ultrasound can use management strategies based on monitoring and delivery methods. One of these monitoring techniques is an umbilical artery Doppler. This method has been shown to decrease risk of morbidity and mortality before and after parturition among IUGR patients.

Time of delivery is also a management strategy and is based on parameters collected from the umbilical artery doppler. Some of these include: pulsatility index, resistance index, and end-diastolic velocities, which are measurements of the fetal circulation.

Pregnant patients may have bleeding from the reproductive tract due to trauma, including sexual trauma, neoplasm, most commonly cervical cancer, and hematologic disorders. Molar pregnancy (also called hydatiform mole) is a type of pregnancy where the sperm and the egg have joined within the uterus, but the result is a cyst resembling a grape-like cluster rather than an embryo. Bleeding can be an early sign of this tumor developing.

Miscarriage is the loss of a pregnancy prior to 20 weeks. In the UK miscarriage is defined as the loss of a pregnancy during the first 23 weeks.

With treatment, maternal mortality is about 1 percent, although complications such as placental abruption, acute renal failure, subcapsular liver hematoma, permanent liver damage, and retinal detachment occur in about 25% of women. Perinatal mortality (stillbirths plus death in infancy) is between 73 and 119 per 1000 babies of woman with HELLP, while up to 40% are small for gestational age. In general, however, factors such as gestational age are more important than the severity of HELLP in determining the outcome in the baby.

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.

Unfractionated heparin, low molecular weight heparin, warfarin (not to be used during pregnancy) and aspirin remain the basis of antithrombotic treatment and prophylaxis both before and during pregnancy.

While the consensus among physicians is the safety of the mother supersedes the safety of the developing fetus, changes in the anticoagulation regimen during pregnancy can be performed to minimize the risks to the developing fetus while maintaining therapeutic levels of anticoagulants in the mother.

The main issue with anticoagulation in pregnancy is that warfarin, the most commonly used anticoagulant in chronic administration, is known to have teratogenic effects on the fetus if administered in early pregnancy. Still, there seems to be no teratogenic effect of warfarin before six weeks of gestation. However, unfractionated heparin and low molecular weight heparin do not cross the placenta.

Early neonatal mortality refers to a death of a live-born baby within the first seven days of life, while late neonatal mortality covers the time after 7 days until before 28 days. The sum of these two represents the neonatal mortality. Some definitions of the PNM include only the early neonatal mortality. Neonatal mortality is affected by the quality of in-hospital care for the neonate. Neonatal mortality and postneonatal mortality (covering the remaining 11 months of the first year of life) are reflected in the Infant Mortality Rate.

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.

There is no specific treatment, but is monitored closely to rapidly identify pre-eclampsia and its life-threatening complications (HELLP syndrome and eclampsia).

Drug treatment options are limited, as many antihypertensives may negatively affect the fetus. Methyldopa, hydralazine, and labetalol are most commonly used for severe pregnancy hypertension.

The fetus is at increased risk for a variety of life-threatening conditions, including pulmonary hypoplasia (immature lungs). If the dangerous complications appear after the fetus has reached a point of viability, even though still immature, then an early delivery may be warranted to save the lives of both mother and baby. An appropriate plan for labor and delivery includes selection of a hospital with provisions for advanced life support of newborn babies.

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.

HELLP syndrome can be difficult to diagnose due to the variability of symptoms among pregnant women (frequently a woman will have no symptoms other than general abdominal pain), and early diagnosis is key in reducing morbidity. If not treated in a timely manner, a woman can become critically ill or die due to liver rupture/hemorrhage or cerebral edema.

In a woman with possible HELLP syndrome, a batch of blood tests is performed: a full blood count, a coagulation panel, liver enzymes, electrolytes, and renal function studies. Often, fibrin degradation product levels are determined, which can be elevated. Lactate dehydrogenase is a marker of hemolysis and is elevated (>600 U/l). Proteinuria is present but can be mild.

In one 1995 study, a positive D-dimer test in the presence of pre-eclampsia was reported to be predictive of woman who will develop HELLP syndrome.

The diagnostic criteria for and subtypes of HELLP vary across studies, which "makes comparison of published data difficult." The classifications include:

- Criteria developed at the University of Tennessee:

- HELLP is characterized by hemolysis on peripheral blood smear with serum lactate dehydrogenase >600 IU/l; serum aspartate aminotransferase >70 IU/l; and platelet count <100,000/μl.

- Partial HELLP syndrome is characterized by one or two features of HELLP.

- Criteria developed at the University of Mississippi, as of 1999:

- "The diagnosis of HELLP syndrome required the presence of thrombocytopenia (perinatal platelet nadir ≤150,000 cells/μl), evidence of hepatic dysfunction (increased aspartate aminotransferase level of ≥40 IU/l, increased alanine aminotransferase level of ≥40 IU/l, or both, with increased lactate dehydrogenase (LDH) level of ≥600 IU/l), and evidence of hemolysis (increased LDH level, progressive anemia)..."

- "Class 1 HELLP syndrome featured severe thrombocytopenia with a platelet nadir of ≤50,000 cells/μl, class 2 HELLP syndrome featured moderate thrombocytopenia with a platelet nadir between >50,000 and ≤100,000 cells/μl, and class 3 HELLP syndrome featured mild thrombocytopenia with a platelet nadir between >100,000 and ≤150,000 cells/μl."

- Criteria developed at the University of Mississippi, as of 2006: "For a patient to merit a diagnosis of HELLP syndrome, class 1 requires severe thrombocytopenia (platelets ≤50,000/μl), evidence of hepatic dysfunction (AST [aspartate aminotransferase] and/or ALT [alanine aminotransferase] ≥70 IU/l), and evidence suggestive of hemolysis (total serum LDH ≥600 IU/l); class 2 requires similar criteria except thrombocytopenia is moderate (>50,000 to ≤100,000/μl); and class 3 includes patients with mild thrombocytopenia (platelets >100,000 but ≤150,000/μl), mild hepatic dysfunction (AST and/or ALT ≥40 IU/l), and hemolysis (total serum LDH ≥600 IU/L)."

It is the goal of evolutionary medicine to find treatments for diseases that are informed by the evolutionary history of a disease. It has been suggested that gestational hypertension is linked to insulin resistance during pregnancy. Both the increase in blood sugar that can lead to gestational diabetes and the increase in blood pressure that can lead to gestational hypertension are mechanisms that mean to optimize the amount of nutrients that can be passed from maternal tissue to fetal tissue. It has been suggested that techniques used to combat insulin insensitivity might also prove beneficial to those suffering from gestational hypertension. Measures to avoid insulin resistance include avoiding obesity before pregnancy, minimizing weight gain during pregnancy, eating foods with low glycemic indexes, and exercising.