Complications of pregnancy

Complications of pregnancy are health problems that are caused by pregnancy. In the immediate postpartum period, 87% to 94% of women report at least one health problem.^[1][2] Long term health problems (persisting after 6 months postpartum) are reported by 31% of women.^[3] Severe complications of pregnancy are present in 1.6% of mothers in the US^[4] and in 1.5% of mothers in Canada.^[5] The relationship between age and complications of pregnancy are now being researched with greater impetus.^[6]

In 2013, complications of pregnancy resulted globally in 293,000 deaths, down from 377,000 deaths in 1990. The most common causes of maternal mortality are maternal bleeding, maternal sepsis and other infections, hypertensive diseases of pregnancy, obstructed labor, and pregnancy with abortive outcome, which includes miscarriage, ectopic pregnancy, and elective abortion.^[7]

There is no clear distinction between complications of pregnancy and symptoms and discomforts of pregnancy. However, the latter do not significantly interfere with activities of daily living or pose any significant threat to the health of the mother or baby. Still, in some cases the same basic feature can manifest as either a discomfort or a complication depending on the severity. For example, mild nausea may merely be a discomfort (morning sickness), but if severe and with vomiting causing water-electrolyte imbalance it can be classified as a pregnancy complication (hyperemesis gravidarum).

Maternal problems

The following problems originate mainly in the mother.

Gestational diabetes

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

Hyperemesis gravidarum

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.^[8][9]

Pelvic girdle pain

• Caused by: Pelvic girdle pain (PGP) disorder is complex and multi-factorial and likely to be represented by a series of sub-groups with different underlying pain drivers from peripheral or central nervous system, altered laxity/stiffness of muscles, laxity to injury of tendinous/ligamentous structures to ‘mal-adaptive’ body mechanics. Musculo-Skeletal Mechanics involved in gait and weight bearing activities can be mild to grossly impaired. PGP can begin peri or postpartum. For most women PGP resolves in weeks after delivery but for some it can last for years resulting in a reduced tolerance for weight bearing activities. PGP affects around 45% of women during pregnancy: 25% report serious pain and 8% are severely disabled.^[10]
• Treatment: The degree of treatment is based on the severity. A mild case would require rest, rehabilitation therapy and pain is usually manageable. More severe cases would also include mobility aids, strong analgesics and sometimes surgery. One of the main factors in helping women cope is with education, information and support. Many treatment options are available.

High blood pressure

Potential severe hypertensive states of pregnancy are mainly:

• Preeclampsia = gestational hypertension, proteinuria (>300 mg), and edema. Severe preeclampsia involves a BP over 160/110 (with additional signs). It affects 5-8% of pregnancies.^[11]
• Eclampsia = seizures in a pre-eclamptic patient, affect around 1.4% of pregnancies.^[12]
• Gestational hypertension
• HELLP syndrome = Hemolytic anemia, Elevated liver enzymes and low platelet count. Incidence is reported as 0.5-0.9% of all pregnancies.^[13]
• Acute fatty liver of pregnancy is sometimes included in the preeclamptic spectrum. It occurs in approximately one in 7,000 to one in 15,000 pregnancies.^[14][15]

Deep vein thrombosis

Deep vein thrombosis (DVT) 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.^[16]

• Caused by: Pregnancy-induced hypercoagulability as a physiological response to potential massive bleeding at childbirth.
• Treatment: Prophylactic treatment, e.g. with low molecular weight heparin may be indicated when there are additional risk factors for deep vein thrombosis.^[16]

Anemia

Levels of hemoglobin are lower in the third trimesters. According to the United Nations (UN) estimates, approximately half of pregnant women suffer from anemia worldwide. Anemia prevalences during pregnancy differed from 18% in developed countries to 75% in South Asia.^[17] Treatment varies due to the severity of the anaemia, and can be used by increasing iron containing foods, oral iron tablets or by the use of parenteral iron.

Infection

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.^[18] Pregnant women are more severely affected by, for example, influenza, hepatitis E, herpes simplex and malaria.^[18] The evidence is more limited for coccidioidomycosis, measles, smallpox, and varicella.^[18] Mastitis, or inflammation of the breast occurs in 20% of lactating women.^[19]

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

Peripartum cardiomyopathy

Peripartum cardiomyopathy is decrease in heart function which occurs in the last month of pregnancy, or up to 6 months post-pregnancy. It increases the risk of congestive heart failure, heart arrhythmias, thromboembolism, and cardiac arrest.^[20]

Hypothyroidism

Hypothyroidism (also called Hashimoto's disease) is an autoimmune disease that affects the thyroid in women. This condition can have a profound effect during pregnancy and on the child. The infant may be seriously affected and have a variety of birth defects. Many women with Hashimoto's disease develop an underactive thyroid. The clinician will do an exam and order one or more tests.^[21][22][23]

Fetal and placental problems

The following problems occur in the fetus or placenta, but may have serious consequences on the mother as well.

Ectopic pregnancy

Ectopic pregnancy is implantation of the embryo outside the uterus

• Caused by: Unknown, but risk factors include smoking, advanced maternal age, and prior damage to the Fallopian tubes.
• Treatment: In most cases, keyhole surgery must be carried out to remove the fetus, along with the Fallopian tube. If the pregnancy is very early, it may resolve on its own, or it can be treated with methotrexate, an abortifacient.^[24]

Miscarriage

Miscarriage is the loss of a pregnancy prior to 20 weeks.^[25] In the UK miscarriage is defined as the loss of a pregnancy during the first 23 weeks.^[26]

Placental abruption

Placental abruption is separation of the placenta from the uterus.

• Caused by: Various causes; risk factors include maternal hypertension, trauma, and drug use.
• Treatment: Immediate delivery if the fetus is mature (36 weeks or older), or if a younger fetus or the mother is in distress. In less severe cases with immature fetuses, the situation may be monitored in hospital, with treatment if necessary.

Placenta praevia

Placenta praevia is when the placenta fully or partially covers the cervix.

Multiple pregnancies

Multiples may become monochorionic, sharing the same chorion, with resultant risk of twin-to-twin transfusion syndrome. Monochorionic multiples may even become monoamniotic, sharing the same amniotic sac, resulting in risk of umbilical cord compression and entanglement. In very rare cases, there may be conjoined twins, possibly impairing function of internal organs.

Vertically transmitted infection

The embryo and fetus have little or no immune function. They depend on the immune function of their mother. Several pathogens can cross the placenta and cause (perinatal) infection. Often microorganisms that produce minor illness in the mother are very dangerous for the developing embryo or fetus. This can result in spontaneous abortion or major developmental disorders. For many infections, the baby is more at risk at particular stages of pregnancy. Problems related to perinatal infection are not always directly noticeable.

The term TORCH complex refers to a set of several different infections that may be caused by transplacental infection.

Babies can also become infected by their mother during birth. During birth, babies are exposed to maternal blood and body fluids without the placental barrier intervening and to the maternal genital tract. Because of this, blood-borne microorganisms (Hepatitis B, HIV), organisms associated with sexually transmitted disease (e.g., Gonorrhoea and Chlamydia), and normal fauna of the genito-urinary tract (e.g., Candida) are among those commonly seen in infection of newborns.

Intrauterine bleeding

There have been rare but known cases of intra-uterine bleeding caused by injury inflicted by the fetus with its fingernails or toenails.^[27]

Complications following childbirth

Haemorrhage

Primary postpartum haemorrhage is blood loss following childbirth of more that 500ml (minor) or 1000ml (major) ^[28] Secondary postpartum haemorrhage is abnormal or excessive bleeding after 24 hours and before 12 weeks postnatally.^[29]

Perineal tearing

Perineal tearing is the spontaneous (unintended) tearing of the skin and other soft tissue structures which, in women, separate the vagina from the anus. Perineal tearing occurs in 85% of vaginal deliveries.^[30] At 6 months postpartum, 21% of women still report perineal pain^[3] and 11-49% report sexual problems or painful intercourse.^[3]

Incontinence

Urinary incontinence and fecal incontinence have been linked to all methods of childbirth, with the incidence of urinary incontinence at 6 months postpartum being 3-7% and fecal incontinence 1-3%.^[3]

Postpartum depression

Postpartum depression is a moderate to severe depressive episode starting anytime during pregnancy or within the four weeks following delivery. It occurs in 4-20% of pregnancies, depending on its definition.^[3] In 38% of the cases of postpartum depression, women are still depressed 3 years postpartum.^[31] In 0.2% of pregnancies, postpartum depression leads to psychosis.^[32]

Posttraumatic stress disorder

Research indicates that 13.6% of women suffer from symptoms of Posttraumatic stress disorder at 6 months postpartum.^[33]

General risk factors

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.^[34] These pre-existing factors may relate to physical and/or mental health, and/or to social issues, or a combination.^[35]

Some common risk factors include:

• Age of either parent
  • Adolescent parents
    Further information: Teenage_pregnancy § Medical_outcomes
  • Older parents
    Further information: Paternal age, Maternal age effect, and Pregnancy over age 50
• 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.^[36] Also, it causes 30% higher odds of the baby being born prematurely.^[37]
  • 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.^[38] Other investigations have revealed short-term neonatal outcomes to include small deficits in infant neurobehavioral function and growth restriction when compared to control infants.^[39] Also, prenatal methamphetamine use is believed to have long-term effects in terms of brain development, which may last for many years.^[38]
  • Cannabis in pregnancy is possibly associated with adverse effects on the child later in life.
• Exposure to Pharmaceutical drugs in pregnancy.^[35] Anti-depressants, for example, may increase risks of such outcomes as preterm delivery.^[40]
  Further information: Pregnancy category
  • 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.^[35]
• 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.^[35]
• 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.^[41][42]
• 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.^[35]
• 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.^[35]
• 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.

High-risk 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 reproductive organs, some of which are listed above) and diseases acquired at any time during the woman's life.

Low-risk pregnancy

A Dutch 2010 research showed that "low-risk" pregnancy in the Netherlands may actually carry a higher risk of perinatal death than a "high-risk" pregnancy.^[43]

See also

• extensive List of Obstetrical complications
• List of obstetric topics
• Dermatoses of pregnancy
• Thyroid in pregnancy
• Reproductive Health Supplies Coalition

References