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Complications of pregnancy

Medical condition

  • 24 min read
  • 4 chapters
810 women die every day from preventable causes related to pregnancy and childbirth, 94% occur in low and lower middle-income countries
UN Women · CC BY-SA 3.0 igo

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Common complications of pregnancy include anemia, gestational diabetes, infections, gestational hypertension, and pre-eclampsia. Presence of these types of complications can have implications on monitoring lab work, imaging, and medical management during pregnancy.

Severe complications of pregnancy, childbirth, and the puerperium are present in 1.6% of mothers in the US, and in 1.5% of mothers in Canada. In the immediate postpartum period (puerperium), 87% to 94% of women report at least one health problem. Long-term health problems (persisting after six months postpartum) are reported by 31% of women.

In 2016, complications of pregnancy, childbirth, and the puerperium resulted in 230,600 deaths globally, down from 377,000 deaths in 1990. The most common causes of maternal mortality are maternal bleeding, postpartum infections including sepsis, hypertensive diseases of pregnancy, obstructed labor, and unsafe abortion.

Complications of pregnancy can sometimes arise from abnormally severe presentations of symptoms and discomforts of pregnancy, which usually do not significantly interfere with activities of daily living or pose any significant threat to the health of the birthing person or fetus. For example, morning sickness is a fairly common mild symptom of pregnancy that generally resolves in the second trimester, but hyperemesis gravidarum is a severe form of this symptom that sometimes requires medical intervention to prevent electrolyte imbalance from severe vomiting.

Maternal problems

The following problems originate in the mother; however, they may have serious consequences for the fetus as well.

Gestational diabetes

Gestational diabetes is when a woman, without a previous diagnosis of diabetes, develops high blood sugar levels during pregnancy. There are many non-modifiable and modifiable risk factors that lead to the development of this complication. Non-modifiable risk factors include a family history of diabetes, advanced maternal age, and ethnicity. Modifiable risk factors include maternal obesity. There is an elevated demand for insulin during pregnancy which leads to increased insulin production from pancreatic beta cells. The elevated demand results from increased maternal calorie intake, weight gain, and increased prolactin and growth hormone production. Gestational diabetes increases the risk for further maternal and fetal complications such as the development of pre-eclampsia, the need for cesarean delivery, preterm delivery, polyhydramnios, macrosomia, shoulder dystocia, fetal hypoglycemia, hyperbilirubinemia, and admission into the neonatal intensive care unit. The increased risk is correlated with how well the gestational diabetes is controlled during pregnancy, with poor control associated with worsened outcomes. A multidisciplinary approach is used to treat gestational diabetes. It involves monitoring blood-glucose levels, nutritional and dietary modifications, lifestyle changes such as increasing physical activity, maternal weight management, and medication such as insulin.

Hyperemesis gravidarum

Hyperemesis gravidarum is the presence of severe and persistent vomiting, causing dehydration and weight loss. It is similar, although more severe than the common morning sickness. It is estimated to affect 0.3–3.6% of pregnant women and is the greatest contributor to hospitalizations under 20 weeks of gestation. Most often, nausea and vomiting symptoms during pregnancy are resolved in the first trimester; however, some continue to experience symptoms. Hyperemesis gravidarum is diagnosed by the following criteria: greater than 3 vomiting episodes per day, ketonuria, and weight loss of more than 3 kg or 5% of body weight. Several non-modifiable and modifiable risk factors predispose women to the development of this condition, such as a female fetus, psychiatric illness history, high or low BMI pre-pregnancy, young age, African American or Asian ethnicity, type I diabetes, multiple pregnancies, and a history of pregnancy affected by hyperemesis gravidarum. There are currently no known mechanisms for the cause of this condition. This complication can cause nutritional deficiency, low pregnancy weight gain, dehydration, and vitamin, electrolyte, and acid-based disturbances in the mother. It has been shown to cause low birth weight, small size for gestational age, preterm birth, and poor APGAR scores in the infant. Treatments for this condition focus on preventing harm to the fetus while improving symptoms and commonly include fluid replacement and consumption of small, frequent, bland meals. First-line treatments include ginger and acupuncture. Second-line treatments include vitamin B6 ± doxylamine, antihistamines, dopamine antagonists, and serotonin antagonists. Third-line treatments include corticosteroids, transdermal clonidine, and gabapentin. Treatments chosen are dependent on the severity of symptoms and response to therapies.

Pelvic girdle pain

Pelvic girdle pain (PGP) disorder is pain in the area between the posterior iliac crest and gluteal fold, beginning peri or postpartum caused by instability and limitation of mobility. It is associated with pubic symphysis pain and sometimes radiation of pain down the hips and thighs. For most pregnant individuals, PGP resolves within three months following delivery, but for some, it can last for years, resulting in a reduced tolerance for weight-bearing activities. PGP affects around 45% of individuals during pregnancy: 25% report serious pain, and 8% are severely disabled. Risk factors for complication development include multiparity, increased BMI, physically strenuous work, smoking, distress, history of back and pelvic trauma, and previous history of pelvic and lower back pain. This syndrome results from a growing uterus during pregnancy that causes increased stress on the lumbar and pelvic regions of the mother, thereby resulting in postural changes and reduced lumbopelvic muscle strength, leading to pelvic instability and pain. It is unclear whether specific hormones in pregnancy are associated with complication development. PGP can result in poor quality of life, predisposition to chronic pain syndrome, extended leave from work, and psychosocial distress. Many treatment options are available based on symptom severity. Non-invasive treatment options include activity modification, pelvic support garments, analgesia with or without short periods of bed rest, and physiotherapy to increase the strength of gluteal and adductor muscles, reducing stress on the lumbar spine. Invasive surgical management is considered a last-line treatment if all other treatment modalities have failed and symptoms are severe.

High blood pressure

Potential severe hypertensive states of pregnancy are mainly:

  • Pre-eclampsia – gestational hypertension, proteinuria (>300 mg), and edema. Severe pre-eclampsia involves a BP over 160/110 (with additional signs). It affects 5–8% of pregnancies.
  • Eclampsia – seizures in a pre-eclamptic patient, affecting around 1.4% of pregnancies.
  • Gestational hypertension can develop after 20 weeks but has no other symptoms and may resolve itself, but it can develop into pre-eclampsia.
  • HELLP syndrome – Hemolytic anemia, elevated liver enzymes and a low platelet count. Incidence is reported as 0.5–0.9% of all pregnancies.
  • Acute fatty liver of pregnancy is sometimes included in the pre-eclamptic spectrum. It occurs in approximately one in 7,000 to one in 15,000 pregnancies.

Women who have chronic hypertension before their pregnancy are at increased risk of complications such as premature birth, low birthweight, or stillbirth. Women who have high blood pressure and had complications in their pregnancy have three times the risk of developing cardiovascular disease compared to women with normal blood pressure who had no complications in pregnancy. Monitoring pregnant women's blood pressure can help prevent both complications and future cardiovascular diseases.

Venous thromboembolism

Venous thromboembolism, consisting of deep vein thrombosis and pulmonary embolism, is a major risk factor for postpartum morbidity and mortality, especially in highly developed countries. A combination of pregnancy-exacerbated hypercoagulability and additional risk factors such as obesity and thrombophilias makes pregnant women vulnerable to thrombotic events The prophylactic measures that include the usage of low molecular weight heparin can significantly reduce risks associated with surgery, particularly in high-risk patients. Awareness among healthcare givers and prompt response in early identification and management of venous thromboembolism during pregnancy and the postpartum period are both crucial for prompt response. Deep vein thrombosis, a form of venous thromboembolism, has an incidence of 0.5 to 7 per 1,000 pregnancies, and is the second most common cause of maternal death in developed countries after bleeding.

  • Caused by: Pregnancy-induced hypercoagulability as a physiological response in preparation for the potential bleeding during childbirth.
  • Treatment: Prophylactic treatment, e.g., with low molecular weight heparin may be indicated when additional risk factors for deep vein thrombosis are present.

Anemia

Anemia is a globally recognized pregnancy complication and is a condition with a low hemoglobin level in one of the trimesters. Such physiological modifications are more pronounced among individuals who suffer from undernutrition as well as chronic diseases associated with hemoglobin reversion, like sickle cell anemia. Prevention of anemia during pregnancy is complicated and is often treated by a team effort of dietary supplementation, iron therapy, and continuous assessment of the mother and fetal indices in a multidisciplinary approach. As an additional measure, emphasis is placed on the astute determination of the respective triggering points, and the application of optimal prenatal care to better maternal and fetal outcome.

Levels of hemoglobin are lower in the third trimester. According to the United Nations (UN) estimates, approximately half of pregnant individuals develop anemia worldwide. Approximately half of pregnant women experience iron deficiency with or without anemia. Anemia prevalence during pregnancy differed from 18% in developed countries to 75% in South Asia; culminating to a global rate of 38% of pregnancies worldwide.

Treatment varies due to the severity of the anaemia, and can be achieved by increasing iron-containing foods, oral iron tablets, or by the use of parenteral iron.

Infection

Pregnancy is a critical period for the expectant mom to experience additional dangers associated with infections. Moreover, a mother and baby's health is exposed to danger when she is in this condition. The prenatal physiology complexity and immunity modulation inherently increase the risk of influenza, hepatitis E, and cytomegalovirus transmission. Avoidance actions like vaccines and strict infectious control protocols can be given priority in the policies aimed at limiting the risk of transmission among high-risk populations. In addition, early diagnosis and management of maternal infections are among the main methods to prevent vertical transmission and fetal aberrations.

A pregnant woman is more susceptible to certain infections. This increased risk is caused by an increased immune tolerance in pregnancy to prevent an immune reaction against the fetus, as well as secondary to maternal physiological changes, including a decrease in respiratory volumes and urinary stasis due to an enlarging uterus. Pregnant individuals are more severely affected by, for example, influenza, hepatitis E, herpes simplex and malaria. The evidence is more limited for coccidioidomycosis, measles, smallpox, and varicella. Mastitis, or inflammation of the breast, occurs in 20% of lactating individuals.

Some infections are vertically transmissible, meaning that they can affect the child as well.

Peripartum cardiomyopathy

Peripartum cardiomyopathy is a heart failure caused by a decrease in left ventricular ejection fraction (LVEF) to <45%, which occurs towards the end of pregnancy or a few months postpartum. Symptoms include shortness of breath in various positions and/or with exertion, fatigue, pedal edema, and chest tightness. Risk factors associated with the development of this complication include maternal age over 30 years, multi-gestational pregnancy, family history of cardiomyopathy, previous diagnosis of cardiomyopathy, pre-eclampsia, hypertension, and African ancestry. The pathogenesis of peripartum cardiomyopathy is not yet known; however, it is suggested that multifactorial potential causes could include autoimmune processes, viral myocarditis, nutritional deficiencies, and maximal cardiovascular changes, which increase cardiac preload. Peripartum cardiomyopathy can lead to many complications such as cardiopulmonary arrest, pulmonary edema, thromboembolisms, brain injury, and death. Treatment of this condition is very similar to treatment of non-gravid heart failure patients; however, the safety of the fetus must be prioritized. For example, for anticoagulation due to increased risk for thromboembolism, low molecular weight heparin, which is safe for use during pregnancy, is used instead of warfarin, which crosses the placenta.

Hypothyroidism

Hypothyroidism (commonly caused by Hashimoto's disease) is an autoimmune disease that affects the thyroid by causing low thyroid hormone levels. Symptoms of hypothyroidism can include low energy, cold intolerance, muscle cramps, constipation, and memory and concentration problems. It is diagnosed by the presence of elevated levels of thyroid-stimulating hormone or TSH. Patients with elevated TSH and decreased levels of free thyroxine or T4 are considered to have overt hypothyroidism. Those with elevated TSH and normal levels of free T4 are considered to have subclinical hypothyroidism. Risk factors for developing hypothyroidism during pregnancy include iodine deficiency, history of thyroid disease, visible goiter, hypothyroidism symptoms, family history of thyroid disease, history of type 1 diabetes or autoimmune conditions, and history of infertility or fetal loss. Various hormones during pregnancy affect the thyroid and increase thyroid hormone demand. For example, during pregnancy, there is increased urinary iodine excretion as well as increased thyroxine binding globulin and thyroid hormone degradation, which all increase thyroid hormone demands. This condition can have a profound effect on the mother and fetus during pregnancy. The infant may be seriously affected and have a variety of birth defects. Complications in the mother and fetus can include pre-eclampsia, anemia, miscarriage, low birth weight, stillbirth, congestive heart failure, impaired neurointellectual development, and, if severe, congenital iodine deficiency syndrome. This complication is treated by iodine supplementation, levothyroxine, which is a form of thyroid hormone replacement, and close monitoring of thyroid function.

Acute fatty liver of pregnancy

Acute fatty liver of pregnancy (ALFP) is a rare but serious complication of pregnancy that can result in extensive morbidity or mortality to the mother and fetus. AFLP happens when fat builds up inside the liver. It is thought to be caused by the buildup of fat cells within the microvesicles of live cells due to mitochondrial dysfunction in fat breakdown (fatty acid β-oxidation). This can prevent the liver from functioning normally; however, its exact mechanism is not clearly understood. Diagnosis is supported by abnormal ultrasound findings of the liver or microvascular fatty infiltration of biopsy of the liver. AFLP may cause symptoms of excessive fatigue, vomiting, stomach pain, or jaundice. Individuals may also have low blood sugar, trouble thinking clearly, or bleeding problems.

Summary of signs and symptoms

  • Vomiting
  • Abdominal pain
  • Excessive thirst/urination
  • Encephalopathy

AFLP is a medical emergency and requires urgent delivery. Children of mothers with ALFP are at risk of low blood sugar, dilated cardiomyopathy, neuromyopathy, and sudden infant death syndrome.

Swansea Criteria for the diagnosis of AFLP. The presence of ≥6 abnormal variables had positive predictive value of 85% and negative predictive value of 100 percent for finding microvascular steatosis:

AFLP can lead to acute liver failure. Acute liver failure is a medical emergency, and prompt recognition and treatment with dialysis, delivery, and other supportive measures have been shown to decrease the risk of both maternal and fetal complications.

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