A pregnancy at risk for serious complications is considered to be a high risk pregnancy.  A high risk pregnancy may be identified by using a scoring system such as the system developed by Hobel et al . [1]  Risk factors are assigned a score corresponding to the degree of risk. A score of 10 or more indicates a high risk pregnancy that should receive more than routine prenatal care. The table below is a modification of Hobel et al's scoring system. 

PREGNANCY RISK ASSESSMENT [1]

OB History Risk Factor	Points
Previous stillbirth	10
Previous neonatal death	10
Previous premature infant	10
Post-term > 42 weeks	10
Fetal blood transfusion for hemolytic disease	10
Repeated miscarriages	5
Previous infant > 10 pounds	5
Six or more completed pregnancies	5
History of eclampsia	5
Previous cesarean section	5
History of preeclampsia	1
History of fetus with anomalies	1
Medical History Risk Factor	Points
Abnormal PAP test	10
Chronic hypertension	10
Heart disease  NYHA Class II-IV (symptomatic)	10
Insulin dependent  diabetes (> A2)	10
Moderate to severe renal disease	10
Previous endocrine ablation	10
Sickle cell disease	10
Epilepsy	5
Heart disease  NYHA  Class I  (no symptoms)	5
History of TB or PPD >= 10 mm	5
Positive serology (for syphilis)	5
Pulmonary disease	5
Thyroid disease	5
Family History	Points
Family history of diabetes	1
Physical Risk Factor Risk Factor	Points
Incompetent cervix	10
Uterine malformations	10
Maternal age 35 and over or 15 and under	5
Maternal weight < 100 pounds or > 200 pounds	5
Small pelvis	5
Current Pregnancy Risk Factor	Points
Abnormal fetal position	10
Moderate to severe preeclampsia	10
Multiple pregnancy	10
Placenta abruptio	10
Placenta previa	10
Polyhydramnios or oligohydramnios	10
Excessive use of drugs/alcohol	5
Gestational diabetes (A1)	5
Kidney infection	5
Mild preeclampsia	5
Rh sensitization only	5
Severe anemia < 9 g/dL hemoglobin	5
Severe flu syndrome or viral disease	5
Vaginal spotting	5
Bladder infection	1
Emotional problems	1
Mild anemia 9 g/dL hemoglobin	1
Moderate alcohol use	1
Smoking >= 1 pack per day	1

REFERENCE
 1. Hobel CJ Hyvarinen MA et al. Prenatal and intrapartum high-risk screening. Am J Obstet Gynecol. 1973; 117: 1-9.