Maternal-Fetal Medicine (also known as high risk pregnancy) is a sub-specialty within Obstetrics and Gynecology that involves pregnancies at risk for complications (see statement by the Society of Maternal Fetal Medicine SMFM).
According to the SMFM, the discipline of Maternal-Fetal Medicine involves the following conditions and patients:

Obstetric complications

• Recurrent pregnancy loss
• Preterm birth prevention
• Asymptomatic (eg, prior second-trimester loss, possible cervical insufficiency)
• Prior preterm birth 
• Mullerian abnormalities
• Short cervical length
• Cervical cerclage
• pessary, progesterone, or other interventions for prevention of PTB
• Symptomatic preterm labor
• Preterm premature rupture of fetal membranes (PPROM)
• Meconium complications
• Malpresentation and malposition
• Shoulder dystocia
• Abnormal third stage of labor
• Placenta accreta, increta, percreta
• Second- or third-trimester vaginal bleeding
• Preeclampsia with severe elements/eclampsia with HELLP syndrome or end-organ damage
• Severe postpartum hemorrhage
• Cesarean hysterectomy
• Acute fatty liver of pregnancy
• Amniotic fluid embolism

MATERNAL COMPLICATIONS

Hypertensive disorders

• Chronic hypertension
• Preeclampsia
• Severe Preeclampsia
• HELLP syndrome

Cardiac disease

• Congenital heart disease
• Arrhythmias
• Valve disease
• Cardiomyopathy
• Pulmonary hypertension
• Coronary artery disease
• Heart transplant
• Cardiac disease (Clark's Group II, III, any valve replacement)

Any antepartum patient admitted for "other than delivery" and patients with postpartum complications 
such as

• severe hemorrhage, 
• refractory infections, 
• complicated preeclampsia, 
• eclampsia and 
• difficult post cesarean complications
• Eating disorders
 
• Severe preeclampsia/eclampsia HELLP syndrome
• Substance abuse
• Transplants

Respiratory disease

• Asthma
• Pneumonia
• Restrictive lung disease
• Pulmonary edema
• Influenza
• Tuberculosis
• Cystic fibrosis

Obesity

 

Endocrinologic disorders

• Addison disease
• Diabetes, insulin-requiring/dependent
• Thyroid disease
• Parathyroid disease
• Pheochromocytoma

Gastrointestinal disease

• Nausea and vomiting in pregnancy; hyperemesis gravidarum
• Eating disorders
• Intrahepatic cholestasis
• Inflammatory bowel disease (ulcerative colitis; Crohn’s disease)
• Gallbladder disease (cholecystitis, cholelithiasis)
• Pregnancy after liver transplantation
• Pancreatitis
• Wilson disease
• Hepatitis
• Acute fatty liver of pregnancy
• Portal hypertension
• Ulcerative colitis
• Crohn's disease

Hematologic diseases

• Maternal anemia and hemoglobinopathies
• Sickle cell disease
• von Willebrand disease
• Thrombotic thrombocytopenia purpura/hemolytic uremic syndrome
• Allo- and autoimmune thrombocytopenia
• Thromboembolic disease, past or current
• Care of the Jehovah’s Witness pregnant woman
• SLE/Other collagen vascular disease

Congenital disorders with potential untoward maternal outcomes:

• Cystic fibrosis
• Marfan's syndrome
• Protein S, C, AT-III deficiency
• Factor 5 Leiden
• Prothrombin mutation

Renal disease (includes renal transplantation)

 

Neurologic diseases:

• Seizure disorders
• Headache
• Multiple sclerosis
• AV malformation
• Berry aneurysm
• Prolactinoma
• Pseudotumor cerebri
• Myasthenia gravis
• Paraplegia/quadriplegia
• Spinal cord injury
• Diabetes insipidus

Psychosocial issues and abuse

• Smoking
• Alcohol abuse
• Drug abuse
• Depression
• Other psychiatric disorders
• Domestic violence

Rheumatologic disorders

• Antiphospholipid syndrome
• Systemic lupus erythematosus
• Rheumatoid arthritis
• Other autoimmune disease

Thromboembolic disorders

• Venous thromboembolism and anticoagulation
• Inherited thrombophilia

Infectious disorders

• Hepatitis A
• Hepatitis B
• Hepatitis C
• Cytomegalovirus (CMV)
• Toxoplasmosis
• Rubella
• Parvovirus
• Varicella
• Herpes
• Coccidomycosis
• Listeria
• HIV
• Gonorrhea
• Chlamydia
• Syphilis
• Trichomonas
• Group B streptococcus
• Vaccination concerns
• Pyelonephritis
• Management of wound infection
• Other life-threatening infections

Trauma and critical care

• Trauma
• Critical care
• Nonobstetric abdominal surgery in the current pregnancy

Skeletal; connective tissue

• Marfan syndrome
• Maternal skeletal dysplasia

Skin Conditions/Dermatoses

 

Fetal anomalies

• Structural abnormalities
• Family history of abnormality
• Aneuploidy or increased risk for aneuploidy
• Teratogen exposure

Fetal complications

• Threatened miscarriage (including medical and surgical management)
• Multifetal pregnancies (including, but not limited to, mono/di twins, mono/mono
• twins, higher-order multiples; fetal growth restriction of 1 fetus; twin-twin transfusion
• syndrome; fetal reduction)
• Growth disorders
• Growth restriction
• Macrosomia
• Infections (eg, cytomegalovirus, toxoplasmosis, parvovirus, Herpes, varicella)
• Fetal death
• Hemolytic disease (red cell alloimmunization)
• Neonatal alloimmune thrombocytopenia
• Nonimmune hydrops
• Immune hydrops

Pregnant women with fetuses at markedly increased risk of adverse outcome, such as:

• Abdominal pregnancy
• Abnormal maternal serum testing
• Fetal hydrops; immune, nonimmune
• Fetal anomaly or cytogenetic abnormality
• Fetal supraventricular tachycardia or congenital heart block
• Incompetent cervix
• Red cell alloimmunization
• Mullerian abnormalities
• Multifetal pregnancies (Twins, Triplets, etc)
• Recurrent prior to preterm deliveries
• Nonobstetric abdominal surgery in the current pregnancy
• Oligohydramnios at <37 weeks gestation
• Placenta accreta, increta, percreta
• Polyhydramnios
• Premature rupture of membranes <34 weeks gestation
• Preterm labor <34 weeks gestation
• Prior second trimester fetal loss
• Prior intrauterine fetal demise
• Recurrent pregnancy loss
• Significant 2nd or 3rd trimester bleeding
• Suspected intrauterine growth restriction
• Twin-to-twin transfusion syndrome

Patients undergoing diagnostic or therapeutic procedures, including:

• Abdominal cerclage
• Chorionic villus sampling
• Comprehensive ultrasound
• Fetal gene therapy
• Fetal blood sampling
• Fetal transfusion
• Fetal muscle/organ biopsy
• Fetal reduction
• Fetal skin sampling
• Fetoscopy/embryoscopy
• Genetic amniocentesis
• Other diagnostic/therapeutic procedures

Fetal testing

Antepartum fetal monitoring

Sonographic assessment of amniotic fluid abnormalities

• Oligohydramnios
• Hydramnios
• Fetal blood sampling/intrauterine transfusion
• Screening for fetal anemia
• Fetal muscle/organ biopsy
• Fetal skin sampling
• Fetal surgery; fetoscopy/embryoscopy

Maternal malignant disease

• Cancer of the Ovary
• Cancer of the Cervix
• Cancer of the Endometrium
• Fallopian Tube Cancer
• Breast Cancer
• Other Cancer