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In a high-risk (at-risk) pregnancy, the mother, fetus, or neonate is at increased risk of morbidity or mortality before or after delivery.
In the US, overall maternal mortality rate is 6/100,000 deliveries; incidence is 3 to 4 times higher in nonwhite women. The most common causes of death are hemorrhage, preeclampsia, pulmonary embolism, and infection.
Perinatal mortality rate in offspring is 11.5/1000 deliveries: 6.7/1000 are fetal, and 4.8/1000 are neonatal (age < 28 days). The most common causes of death are congenital malformations and preterm delivery.
Risk assessment is part of routine prenatal care. Risk is also assessed during or shortly after labor and at any time that events may modify risk status. Risk factors (see Table 1: High-Risk Pregnancy: Pregnancy Risk Assessment ) are assessed systematically because each risk factor present increases overall risk. High-risk pregnancies require close monitoring and sometimes referral to a perinatal center. When referral is needed, transfer before rather than after delivery results in lower neonatal morbidity and mortality rates. The most common reasons for referral before delivery are
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Table 1
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| Pregnancy Risk Assessment |
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Category
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Risk Factors
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Score*
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Preexisting
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Cardiovascular and renal disorders
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Moderate to severe preeclampsia
Chronic hypertension
Moderate to severe renal disorders
Severe heart failure (class II–IV, NYHA classification)
|
10
10
10
10
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History of eclampsia
History of pyelitis (infection of the renal pelvis)
Mild heart failure (class I, NYHA classification)
Mild preeclampsia
Acute pyelonephritis
|
5
5
5
5
5
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History of cystitis
Acute cystitis
History of preeclampsia
|
1
1
1
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Metabolic disorders
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Insulin-dependent diabetes
Previous endocrine ablation
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10
10
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Thyroid disorders
Gestational diabetes
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5
5
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Family history of diabetes
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1
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Obstetric history
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Fetal exchange transfusion because of Rh incompatibility
|
10
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Stillbirth
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10
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Late abortion (16–20 wk)
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10
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Postterm pregnancy (> 42 wk)
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10
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Preterm neonate (< 37 wk and < 2500 g)
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10
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Intrauterine growth restriction (weight < 10th percentile for estimated gestational age)
|
10
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Abnormal fetal position
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10
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Polyhydramnios (hydramnios)
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10
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Multifetal pregnancy
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10
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Previous brachial plexus injury
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10
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Neonatal death
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5
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Cesarean delivery
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5
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Habitual (≥ 3) abortion
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5
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Neonate > 4.5 kg
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5
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Shoulder dystocia
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5
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Multiparity of > 5
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5
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Seizure disorders or cerebral palsy
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5
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Fetal malformations
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1
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Other disorders
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Abnormal cervical cytologic findings
Sickle cell disease
Thrombophilia
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10
10
10
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Positive serologic results for STDs
Severe anemia (Hb < 9 g/dL)
History of TB or purified protein derivative injection site induration ≥ 10 mm
Pulmonary disorders
|
5
5
5
5
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Mild anemia (Hb 9.0–10.9 g/dL)
|
1
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Anatomic abnormalities
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Uterine malformation
Insufficient (incompetent) cervix
|
10
10
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Small pelvis
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5
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Maternal characteristics
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Age ≥ 35 or ≤ 15 yr
Weight < 45.5 or > 91 kg
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5
5
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Psychiatric disorder or intellectual disability (mental retardation)
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1
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Antepartum
|
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Exposure to teratogens
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Certain viral infections (eg, rubella, cytomegalovirus infection)
Flu syndrome (severe)
Excessive use of drugs
|
5
5
5
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Smoking ≥ 1 pack/day
Alcohol (moderate to severe)
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1
1
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Pregnancy complications
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Rh sensitization only
Vaginal spotting
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5
5
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Intrapartum
|
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Maternal
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Moderate to severe preeclampsia
Polyhydramnios (hydramnios) or oligohydramnios
Uterine rupture
Postterm (> 42 wk)
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10
10
10
10
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Mild preeclampsia
Premature rupture of membranes > 12 h
Preterm labor
Primary dysfunctional labor
Secondary arrest of dilation
Labor > 20 h
Second stage > 2.5 h
Medical induction of labor
Precipitous labor (< 3 h)
Primary cesarean delivery
Repeat cesarean delivery
|
5
5
5
5
5
5
5
5
5
5
5
|
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Elective induction of labor
Prolonged latent phase
Oxytocin augmentation
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1
1
1
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Placental
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Placenta previa
Abruptio placentae
Chorioamnionitis
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10
10
10
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Fetal
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Abnormal presentation (breech, brow, face) or transverse lie
Multifetal pregnancy
Fetal bradycardia > 30 min
Prolapsed cord
Fetal weight < 2.5 kg
Fetal acidosis pH ≤ 7
Fetal tachycardia > 30 min
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10
10
10
10
10
10
10
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Operative delivery using vacuum extractor or forceps
Breech delivery, spontaneous or assisted
|
5
5
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*A score of ≥ 10 indicates a high risk.
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NYHA = New York Heart Association; STDs = sexually transmitted diseases.
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Last full review/revision January 2009 by Christian M. Briery, MD; John Morrison, MD
Content last modified January 2013
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