Find information on medical topics, symptoms, drugs, procedures, news and more, written for the health care professional.

* This is a professional Version *

Overview of High-Risk Pregnancy

by Raul Artal, MD

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 ( 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

  • Preterm labor (often due to premature rupture of the membranes)

  • Preeclampsia

  • Hemorrhage

Pregnancy Risk Assessment

Category

Risk Factors

Score*

Preexisting

Cardiovascular and renal disorders

Moderate to severe preeclampsia

10

Chronic hypertension

10

Moderate to severe renal disorders

10

Severe heart failure (class II–IV, NYHA classification)

10

History of eclampsia

5

History of pyelitis (infection of the renal pelvis)

5

Mild heart failure (class I, NYHA classification)

5

Mild preeclampsia

5

Acute pyelonephritis

5

History of cystitis

1

Acute cystitis

1

History of preeclampsia

1

Metabolic disorders

Obesity class III

10

Insulin -dependent diabetes

10

Previous endocrine ablation

10

Thyroid disorders

5

Obesity class II

5

Gestational diabetes

5

Family history of diabetes

1

Obstetric history

Fetal exchange transfusion because of Rh incompatibility

10

Stillbirth

10

Late abortion (16–20 wk)

10

Postterm pregnancy (> 42 wk)

10

Preterm newborn (< 37 wk and < 2500 g)

10

Intrauterine growth restriction (weight < 10th percentile for estimated gestational age)

10

Abnormal fetal position

10

Polyhydramnios (hydramnios)

10

Multifetal pregnancy

10

Previous brachial plexus injury

10

Neonatal death

5

Cesarean delivery

5

Habitual ( 3) abortion

5

Neonate > 4.5 kg

5

Shoulder dystocia

5

Multiparity of > 5

5

Seizure disorders or cerebral palsy

5

Fetal malformations

1

Other disorders

Abnormal cervical cytologic findings

10

Sickle cell disease

10

Thrombophilia

10

Positive serologic results for STDs

5

Severe anemia (Hb < 9 g/dL)

5

History of TB or purified protein derivative injection site induration 10 mm

5

Pulmonary disorders

5

Mild anemia (Hb 9.0–10.9 g/dL)

1

Anatomic abnormalities

Uterine malformation

10

Insufficient (incompetent) cervix

10

Small pelvis

5

Maternal characteristics

Age 35 or 15 yr

5

Weight < 45.5 or > 91 kg

5

Psychiatric disorder or intellectual disability

1

Antepartum

Exposure to teratogens

Group B streptococcal infections

10

Certain viral infections (eg, rubella, cytomegalovirus infections)

5

Flu syndrome (severe)

5

Excessive use of drugs

5

Smoking 1 pack/day

1

Alcohol (moderate to severe)

1

Pregnancy complications

Preterm labor at < 37 wk

10

Preterm premature rupture of membranes

10

Rh sensitization only (not requiring an exchange transfusion)

5

Vaginal spotting

5

Intrapartum

Maternal

Moderate to severe preeclampsia

10

Polyhydramnios (hydramnios) or oligohydramnios

10

Uterine rupture

10

Postterm (> 42 wk)

10

Mild preeclampsia

5

Premature rupture of membranes > 12 h

5

Preterm labor at ≥ 37 wk

5

Primary dysfunctional labor

5

Secondary arrest of dilation

5

Labor > 20 h

5

Second stage > 2.5 h

5

Medical induction of labor

5

Precipitous labor (< 3 h)

5

Primary cesarean delivery

5

Repeat cesarean delivery

5

Elective induction of labor

1

Prolonged latent phase

1

Oxytocin augmentation

1

Placental

Placenta previa

10

Abruptio placentae

10

Chorioamnionitis

10

Fetal

Abnormal presentation (breech, brow, face) or transverse lie

10

Multifetal pregnancy

10

Fetal bradycardia > 30 min

10

Prolapsed cord

10

Fetal weight < 2.5 kg

10

Fetal weight > 4 kg

10

Fetal acidosis pH 7

10

Fetal tachycardia > 30 min

10

Operative delivery using vacuum extractor or forceps

5

Breech delivery, spontaneous or assisted

5

*A score of 10 or more indicates a high risk.

National Institutes of Health's obesity classes based on BMI:

  • Class I: 30–34.9

  • Class II: 35–39.9

  • Class III: > 40

NYHA = New York Heart Association; STDs = sexually transmitted diseases.

Resources In This Article

Drugs Mentioned In This Article

  • Drug Name
    Select Trade
  • PITOCIN

* This is a professional Version *