Swelling (especially in the hands and face) was originally considered an important sign for a diagnosis of pre-eclampsia. However, because swelling is a common occurrence in pregnancy, its utility as a distinguishing factor in pre-eclampsia is not high. Pitting edema (unusual swelling, particularly of the hands, feet, or face, notable by leaving an indentation when pressed on) can be significant, and should be reported to a health care provider.

In general, none of the signs of pre-eclampsia are specific, and even convulsions in pregnancy are more likely to have causes other than eclampsia in modern practice. Further, a symptom such as epigastric pain may be misinterpreted as heartburn. Diagnosis, therefore, depends on finding a coincidence of several pre-eclamptic features, the final proof being their regression after delivery.

HELLP syndrome is defined as hemolysis (microangiopathic), elevated liver enzymes (liver dysfunction), and low platelets (thrombocytopenia). This condition may occur in 10–20% of patients with severe pre-eclampsia and eclampsia and is associated with increased maternal and fetal morbidity and mortality. In 50% of instances, HELLP syndrome develops preterm, while 20% of cases develop in late gestation and 30% during the post-partum period.

The seizures of eclampsia typically present during pregnancy and prior to delivery (the antepartum period), but may also occur during labor and delivery (the intrapartum period) or after the baby has been delivered (the postpartum period). If postpartum seizures develop, it is most likely to occur within the first 48 hours after delivery. However, late postpartum seizures of eclampsia may occur as late as 4 weeks after delivery.

Unfortunately, there is no single test to predict or diagnose preeclampsia. Key signs are increased blood pressure and protein in the urine (proteinuria). Other symptoms that seem to occur with preeclampsia include persistent headaches, blurred vision or sensitivity to light, and abdominal pain.

All of these sensations can be caused by other disorders; they can also occur in healthy pregnancies. Regular visits are scheduled to track blood pressure and level of protein in urine, to order and analyze blood tests that detect signs of preeclampsia, and to monitor fetal development more closely.

No single diagnostic test currently exists to predict the likelihood of developing gestational hypertension. High blood pressure is the major sign in diagnosing gestational hypertension. Protein in the urine, proteinuria, is a key indicator of the condition. Some women with gestational hypertension may present asymptomatic, but a number of symptoms are associated with the condition.

Symptoms

- Edema

- Sudden weight gain

- Blurred vision or sensitivity to light

- Nausea and vomiting

- Persistent headaches

- Increased blood pressure

A classification of hypertensive disorders of pregnancy uses 4 categories:

1. chronic hypertension;

2. preeclampsia-eclampsia;

3. preeclampsia superimposed on chronic hypertension;

4. gestational hypertension (transient hypertension of pregnancy or chronic hypertension identified in the latter half of pregnancy).

This terminology is preferred over the older but widely used term pregnancy-induced hypertension (PIH) because it is more precise. The newer terminology reflects simply relation of pregnancy with either the onset or first detection of hypertension and that the question of causation, while pathogenetically interesting, is not the important point for most health care purposes. This classification treats HELLP syndrome as a type of preeclampsia rather than a parallel entity.

Eclampsia is a disorder of pregnancy characterized by seizures in the setting of pre-eclampsia. Typically the pregnant woman develops hypertension and proteinuria before the onset of a convulsion (seizure).

- Long-lasting (persistent) headaches

- Blurry vision

- Photophobia (i.e. bright light causes discomfort)

- Abdominal pain

- Either in the epigastric region (the center of the abdomen above the navel, or belly-button)

- And/or in the right upper quadrant of the abdomen (below the right side of the rib cage)

- Altered mental status (confusion)

Any of these symptoms may present before or after a seizure occurs. It is also possible that none of these symptoms will develop.

Other cerebral signs may immediately precede the convulsion, such as nausea, vomiting, headaches, and cortical blindness. If the complication of multi-organ failure ensues, signs and symptoms of those failing organs will appear, such as abdominal pain, jaundice, shortness of breath, and diminished urine output.

Gestational hypertension or pregnancy-induced hypertension (PIH) is the development of new hypertension in a pregnant woman after 20 weeks gestation without the presence of protein in the urine or other signs of preeclampsia. Hypertension is defined as having a blood pressure

greater than 140/90 mm Hg.

There are 2 major categories of IUGR: symmetrical and asymmetrical. Some conditions are associated with both symmetrical and asymmetrical growth restriction.

Asymmetrical IUGR is more common (70%). In asymmetrical IUGR, there is restriction of weight followed by length. The head continues to grow at normal or near-normal rates (head sparing). A lack of subcutaneous fat leads to a thin and small body out of proportion with the liver. Normally at birth the brain of the fetus is 3 times the weight of its liver. In IUGR, It becomes 5-6 times. In these cases, the embryo/fetus has grown normally for the first two trimesters but encounters difficulties in the third, sometimes secondary to complications such as pre-eclampsia. Other symptoms than the disproportion include dry, peeling skin and an overly-thin umbilical cord. The baby is at increased risk of hypoxia and hypoglycaemia. This type of IUGR is most commonly caused by extrinsic factors that affect the fetus at later gestational ages. Specific causes include:

- Chronic high blood pressure

- Severe malnutrition

- Genetic mutations, Ehlers–Danlos syndrome

Preterm infants usually show physical signs of prematurity in reverse proportion to the gestational age. As a result, they are at risk for numerous medical problems affecting different organ systems.

- Neurological problems include apnea of prematurity, hypoxic-ischemic encephalopathy (HIE), retinopathy of prematurity (ROP), developmental disability, transient hyperammonemia of the newborn, cerebral palsy and intraventricular hemorrhage, the latter affecting 25 percent of babies born preterm, usually before 32 weeks of pregnancy. Mild brain bleeds usually leave no or few lasting complications, but severe bleeds often result in brain damage or even death. Neurodevelopmental problems have been linked to lack of maternal thyroid hormones, at a time when their own thyroid is unable to meet postnatal needs.

- Cardiovascular complications may arise from the failure of the ductus arteriosus to close after birth: patent ductus arteriosus (PDA).

- Respiratory problems are common, specifically the respiratory distress syndrome (RDS or IRDS) (previously called hyaline membrane disease). Another problem can be chronic lung disease (previously called bronchopulmonary dysplasia or BPD).

- Gastrointestinal and metabolic issues can arise from neonatal hypoglycemia, feeding difficulties, rickets of prematurity, hypocalcemia, inguinal hernia, and necrotizing enterocolitis (NEC).

- Hematologic complications include anemia of prematurity, thrombocytopenia, and hyperbilirubinemia (jaundice) that can lead to kernicterus.

- Infection, including sepsis, pneumonia, and urinary tract infection

A study of 241 children born between 22 and 25 weeks who were currently of school age found that 46 percent had severe or moderate disabilities such as cerebral palsy, vision or hearing loss and learning problems. 34 percent were mildly disabled and 20 percent had no disabilities, while 12 percent had disabling cerebral palsy.

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.

Preterm birth causes a range of problems.

The main categories of causes of preterm birth are preterm labor induction and spontaneous preterm labor. Signs and symptoms of preterm labor include four or more uterine contractions in one hour. In contrast to false labour, true labor is accompanied by cervical dilatation and effacement. Also, vaginal bleeding in the third trimester, heavy pressure in the pelvis, or abdominal or back pain could be indicators that a preterm birth is about to occur. A watery discharge from the vagina may indicate premature rupture of the membranes that surround the baby. While the rupture of the membranes may not be followed by labor, usually delivery is indicated as infection (chorioamnionitis) is a serious threat to both fetus and mother. In some cases, the cervix dilates prematurely without pain or perceived contractions, so that the mother may not have warning signs until very late in the birthing process.

A review into using uterine monitoring at home to detect contractions and possible preterm births in women at higher risk of having a preterm baby found that it did not reduce the number of preterm births. The research included in the review was poor quality but it showed that home monitoring may increase the number of unplanned antenatal visits and may reduce the number of babies admitted to special care when compared with women receiving normal antenatal care.

HELLP usually begins during the third trimester; rare cases have been reported as early as 21 weeks gestation. Often, a woman who develops HELLP syndrome has already been followed up for pregnancy-induced hypertension (gestational hypertension), or is suspected to develop pre-eclampsia (high blood pressure and proteinuria). Up to 8% of all cases occur after delivery.

Women with HELLP syndrome often appear non-toxic. Early symptoms can include:

- In 90% of cases, either epigastric pain described as "heartburn" or right upper quadrant pain develops.

- In 90% of cases, malaise occurs.

- In 50% of cases, nausea or vomiting happen.

Gradual but marked onset of headaches (30%), blurred vision, and paresthesia (tingling in the extremities) can occur. Edema may occur, but its absence does not exclude HELLP syndrome. Arterial hypertension is a diagnostic requirement, but may be mild. Rupture of the liver capsule and a resultant hematoma may occur. If a woman has a seizure or coma, the condition has progressed into full-blown eclampsia.

Disseminated intravascular coagulation is also seen in about 20% of all women with HELLP syndrome, and in 84% when HELLP is complicated by acute renal failure. Pulmonary edema is found in 6% of all women with HELLP syndrome, and when HELLP is complicated by acute renal failure, pulmonary edema is found in 44% of women with the syndrome.

A woman with symptoms of HELLP can be misdiagnosed in the early stages, increasing the risk of liver failure and morbidity. Rarely, after a caesarean section surgery, a woman may have signs and symptoms of a shock condition mimicking either pulmonary embolism or reactionary haemorrhage.

Low birth weight (LBW) is defined by the World Health Organization as a birth weight of a

infant of 2,499 g or less, regardless of gestational age. Subcategories include very low birth weight (VLBW), which is less than 1500 g (3 pounds 5 ounces), and extremely low birth weight (ELBW), which is less than 1000 g (2 pounds 3 ounces). Normal weight at term delivery is 2500–4200 g (5 pounds 8 ounces – 9 pounds 4 ounces).

Intrauterine hypoxia occurs when the fetus is deprived of an adequate supply of oxygen. It may be due to a variety of reasons such as prolapse or occlusion of the umbilical cord, placental infarction and maternal smoking. Intrauterine growth restriction (IUGR) may cause or be the result of hypoxia. Intrauterine hypoxia can cause cellular damage that occurs within the central nervous system (the brain and spinal cord). This results in an increased mortality rate, including an increased risk of sudden infant death syndrome (SIDS). Oxygen deprivation in the fetus and neonate have been implicated as either a primary or as a contributing risk factor in numerous neurological and neuropsychiatric disorders such as epilepsy, ADHD, eating disorders and cerebral palsy.

HELLP syndrome is a life-threatening pregnancy complication usually considered to be a variant or complication of pre-eclampsia. Both conditions usually occur during the later stages of pregnancy, or sometimes after childbirth. "HELLP" is an abbreviation of the three main features of the syndrome: Hemolysis, Elevated Liver enzymes, and Low Platelet count. The syndrome may be associated with serious liver manifestations, including death of liver cells due to inadequate blood flow and oxygen delivery, bleeding, and rupture.

Hypercoagulability in pregnancy is the propensity of pregnant women to develop thrombosis (blood clots). Pregnancy itself is a factor of hypercoagulability (pregnancy-induced hypercoagulability), as a physiologically adaptive mechanism to prevent "post partum" bleeding. However, when combined with an additional underlying hypercoagulable states, the risk of thrombosis or embolism may become substantial.

LBW is either caused by preterm birth (that is, a low gestational age at birth, commonly defined as younger than 37 weeks of gestation) or the infant being small for gestational age (that is, a slow prenatal growth rate), or a combination of both.

In general, risk factors in the mother that may contribute to low birth weight include young ages, multiple pregnancies, previous LBW infants, poor nutrition, heart disease or hypertension, untreated coeliac disease, drug addiction, alcohol abuse, and insufficient prenatal care. Environmental risk factors include smoking, lead exposure, and other types of air pollutions.

Pregnancy-induced hypercoagulability is probably a physiologically adaptive mechanism to prevent "post partum" hemorrhage. Pregnancy changes the plasma levels of many clotting factors, such as fibrinogen, which can rise up to three times its normal value. Thrombin levels increase. Protein S, an anticoagulant, decreases. However, the other major anticoagulants, protein C and antithrombin III, remain constant. Fibrinolysis is impaired by an increase in plasminogen activator inhibitor-1 (PAI-1 or PAI) and plasminogen activator inhibitor-2 (PAI-2), the latter synthesized from the placenta. Venous stasis may occur at the end of the first trimester, due to enhanced compliance of the vessel walls by a hormonal effect.

Also, pregnancy can cause hypercoagulability by other factors, e.g. the prolonged bed rest that often occurs "post partum" that occurs in case of delivery by forceps, vacuum extractor or Caesarean section.

A study of more than 200,000 women came to the result that admission to inpatient care during pregnancy was associated with an 18-fold increase in the risk of venous thromboembolism (VTE) during the stay, and a 6-fold increase in risk in the four weeks after discharge, compared with pregnant women who did not require hospitalization. The study included women admitted to hospital for one or more days for reasons other than delivery or venous thromboembolism.

Pregnancy after the age of 35 augments the risk of VTE, as does multigravidity of more than four pregnancies.

Pregnancy in itself causes approximately a five-fold increased risk of deep venous thrombosis. Several pregnancy complications, such as pre-eclampsia, cause substantial hypercoagulability.

Hypercoagulability states as a pre-existing condition in pregnancy include both acquired ones, such as antiphospholipid antibodies, and congenital ones, including factor V Leiden, prothrombin mutation, proteins C and S deficiencies, and antithrombin III deficiency.

There are various causes for intrauterine hypoxia (IH). The most preventable cause is maternal smoking. Cigarette smoking by expectant mothers has been shown to have a wide variety of deleterious effects on the developing fetus. Among the negative effects are carbon monoxide induced tissue hypoxia and placental insufficiency which causes a reduction in blood flow from the uterus to the placenta thereby reducing the availability of oxygenated blood to the fetus. Placental insufficiency as a result of smoking has been shown to have a causal effect in the development of pre-eclampsia. While some previous studies have suggested that carbon monoxide from cigarette smoke may have a protective effect against preeclampsia, a recent study conducted by the Genetics of Pre-Eclampsia Consortium (GOPEC) in the United Kingdom found that smokers were five times more likely to develop pre-eclampsia.

Nicotine alone has been shown to be a teratogen which affects the autonomic nervous system, leading to increased susceptibility to hypoxia-induced brain damage.

Maternal anemia in which smoking has also been implicated is another factor associated with IH/BA. Smoking by expectant mothers causes a decrease in maternal nucleated red blood cells (NRBC), thereby reducing the amount of red blood cells available for oxygen transport.

The perinatal brain injury occurring as a result of birth asphyxia, manifesting within 48 hours of birth, is a form of hypoxic ischemic encephalopathy.

Failure to thrive, seizures, irritability, lack of energy, and difficulty in breathing can be associated with hypertension in newborns and young infants. In older infants and children, hypertension can cause headache, unexplained irritability, fatigue, failure to thrive, blurred vision, nosebleeds, and facial paralysis.

Hypertension occurs in approximately 8–10% of pregnancies. Two blood pressure measurements six hours apart of greater than 140/90 mm Hg is diagnostic of hypertension in pregnancy. High blood pressure in pregnancy can be classified as pre-existing hypertension, gestational hypertension, or pre-eclampsia.

Pre-eclampsia is a serious condition of the second half of pregnancy and following delivery characterised by increased blood pressure and the presence of protein in the urine. It occurs in about 5% of pregnancies and is responsible for approximately 16% of all maternal deaths globally. Pre-eclampsia also doubles the risk of death of the baby around the time of birth. Usually there are no symptoms in pre-eclampsia and it is detected by routine screening. When symptoms of pre-eclampsia occur the most common are headache, visual disturbance (often "flashing lights"), vomiting, pain over the stomach, and swelling. Pre-eclampsia can occasionally progress to a life-threatening condition called eclampsia, which is a hypertensive emergency and has several serious complications including vision loss, brain swelling, seizures, kidney failure, pulmonary edema, and disseminated intravascular coagulation (a blood clotting disorder).

In contrast, gestational hypertension is defined as new-onset hypertension during pregnancy without protein in the urine.

Hypertensive encephalopathy is most commonly encountered in young and middle-aged people who have hypertension. Overall, the condition is rare even among people with hypertension. Studies report that from 0.5 to 15% of people with malignant hypertension develop hypertensive encephalopathy. With the development of methods for detection and treatment of hypertension, hypertensive encephalopathy has been becoming more rare.

Symptoms of hypertensive encephalopathy typically start to occur 12–48 hours after a sudden and sustained increase in blood pressure. The first manifestation of these symptoms is a severe headache. Headache occurs in greater than 75% of patients. The patient becomes restless. Alterations in consciousness may follow several hours later, which include impaired judgement and memory, confusion, somnolence and stupor. If the condition is not treated, these neurological symptoms may worsen and ultimately turn into a coma. Other symptoms may include increased irritability, vomiting, diplopia, seizures, twitching and myoclonus of the limbs. Alterations in vision (vision blurring, hemivisual field defects, color blindness, cortical blindness) are common. They occur in 4 out of 11 cases (Jellinek et al. 1964). Hemiparesis, intracerebral hemorrhage, aphasia may also occur, but they are less common.