A high-risk pregnancy is one in which the pregnant client or fetus has a higher-than-usual chance of illness or death. Risk is identified at the first visit and reassessed throughout pregnancy, because new problems can arise at any time.

Common risk factors

Overview of major high-risk conditions (details in their own topics)

Adolescent pregnancy

• Higher risk of preterm birth, low birth weight, anemia, hypertensive disorders, STIs, late or limited prenatal care, and depression
• Priority assessment: social support, emotional readiness, relationship safety, schooling, nutrition (calcium 1,300 mg/day; iron)
• Use a nonjudgmental approach and respect confidentiality

Advanced maternal age (35 or older) — higher risk of chromosomal abnormalities, pregnancy loss, gestational diabetes, preeclampsia, placenta previa, cesarean birth, and stillbirth; antenatal fetal testing may be offered late in pregnancy.

Heart disease in pregnancy

• The roughly 40–50% rise in blood volume and cardiac output stresses a diseased heart
• Highest-risk periods: the late second to early third trimester (peak volume, about 28–32 weeks), labor and birth (each contraction adds blood to the circulation), and the first hours to days after birth (autotransfusion from the contracted uterus and mobilization of extravascular fluid)
• Functional class (NYHA) and the modified WHO classification guide care; peripartum cardiomyopathy may appear in late pregnancy or the months after birth

Rh (D) alloimmunization

• An Rh-negative pregnant person carrying an Rh-positive fetus can be exposed to fetal red cells (birth, bleeding, trauma, procedures, loss) and form anti-D antibodies
• The first pregnancy is usually unaffected; in later pregnancies, maternal IgG anti-D crosses the placenta and destroys fetal red cells → hemolytic disease of the fetus and newborn: anemia, jaundice, and in severe cases hydrops fetalis
• Prevention with Rh immune globulin (RhIG) is the key nursing role

Cervical insufficiency — painless cervical dilation in the second trimester without contractions, leading to pregnancy loss or preterm birth. Risk factors: prior second-trimester loss, cervical surgery (cone biopsy, LEEP), cervical trauma, congenital factors.

Hyperemesis gravidarum (HG)

• Nausea and vomiting of pregnancy (NVP) affects most pregnant people and usually settles by 16–20 weeks
• HG is the most severe end: persistent vomiting not explained by other causes, with weight loss (commonly ≥ 5% of prepregnancy weight), ketonuria, dehydration, and electrolyte imbalance
• Linked to high hCG and estrogen: risk is higher with multiple gestation, molar pregnancy, HG in a previous pregnancy, and history of motion sickness or migraine
• Prolonged vomiting → loss of gastric acid and potassium → hypokalemia, hypochloremic metabolic alkalosis; starvation → fat breakdown → ketones (ketosis, and acidosis in severe cases)

Hyperemesis gravidarum

• Frequency, amount, and character of vomiting (bile, blood), ability to keep fluids down, triggers
• Dehydration: dry mucous membranes, poor skin turgor, tachycardia, hypotension, concentrated or decreased urine
• Daily weight and percentage loss
• Signs of hypokalemia (weakness, dysrhythmias), confusion or ataxia (Wernicke encephalopathy)
• Emotional impact: anxiety, depression, inability to work or care for family
• Headache, visual changes, or rising BP with HG before 20 weeks → suspect molar pregnancy (early preeclampsia)

Heart disease — distinguish normal pregnancy symptoms from decompensation: worsening dyspnea, orthopnea, cough, crackles, palpitations, progressive edema, chest pain, syncope

Rh — blood type, Rh, and antibody screen (indirect Coombs) at the first visit and at 24–28 weeks

HG

• Urine ketones and specific gravity
• Electrolytes (potassium, sodium, chloride), BUN/creatinine, magnesium, phosphate
• Liver enzymes (may be mildly raised), TSH/free T4 (hCG-related transient hyperthyroidism is common and usually needs no treatment)
• Ultrasound to detect multiple gestation or molar pregnancy
• Exclude other causes: gastroenteritis, pancreatitis, cholecystitis, hepatitis, pyelonephritis, bowel obstruction

Rh alloimmunization

• Maternal antibody screen (indirect Coombs) — identifies anti-D and titer
• If sensitized: serial titers, fetal Rh genotyping from maternal blood, middle cerebral artery Doppler for fetal anemia
• Kleihauer–Betke test or flow cytometry quantifies fetal–maternal hemorrhage to calculate RhIG dose
• Newborn: blood type and direct Coombs test

Cervical insufficiency — transvaginal ultrasound cervical length (short cervix < 25 mm before 24 weeks)

Heart disease — ECG, echocardiogram, BNP/NT-proBNP

HG — stepwise treatment

1. Diet and lifestyle changes; ginger
2. Pyridoxine (vitamin B6) alone or with doxylamine — first-line drug therapy. Doxylamine causes drowsiness
3. Add antihistamines (dimenhydrinate, diphenhydramine) or dopamine antagonists: metoclopramide (drowsiness, extrapyramidal effects, tardive dyskinesia — limit duration), prochlorperazine, promethazine (sedation; severe tissue injury if given IV and extravasated — boxed warning; deep IM is preferred, never subcutaneous)
4. Ondansetron — effective; QT prolongation (check ECG and correct potassium and magnesium in at-risk clients), constipation, headache; a possible small increase in some birth defects with first-trimester use is discussed with the client
5. IV fluids for dehydration — isotonic fluids (normal saline or lactated Ringer's) with potassium as needed
6. Thiamine before dextrose-containing fluids (and in prolonged vomiting) — prevents Wernicke encephalopathy. Never delay dextrose for hypoglycemia; give thiamine at the same time
7. Refractory: corticosteroids (after 10 weeks, because of a possible oral cleft risk earlier); enteral or parenteral nutrition

Rh immune globulin (RhIG) — for Rh-negative, unsensitized clients

• At about 28 weeks (300 mcg / 1,500 IU IM)
• Within 72 hours after birth if the newborn is Rh-positive (dose adjusted by Kleihauer–Betke if a large bleed); if missed, give as soon as possible, up to 28 days after birth
• After events that may expose fetal cells: bleeding, abdominal trauma, amniocentesis/CVS, external cephalic version, ectopic or molar pregnancy, pregnancy loss or abortion (ACOG 2024: may be forgone for abortion or pregnancy loss before 12 0/7 weeks)
• Not given if already sensitized (antibody screen positive for anti-D not caused by prior RhIG). It is a blood product — obtain consent, give IM (deltoid or gluteal), not IV unless the product is labeled for IV
• Does not help a baby already affected; severe fetal anemia may need intrauterine transfusion

Cervical insufficiency

• History-indicated cerclage at about 12–14 weeks for prior painless second-trimester loss; ultrasound-indicated cerclage for prior preterm birth before 34 weeks and cervical length < 25 mm before 24 weeks; exam-indicated ("rescue") cerclage for painless dilation
• Vaginal progesterone for a short cervix (≤ 20 mm) in a singleton pregnancy
• Elective cerclage removal at 36–37 weeks, or sooner with labor or rupture of membranes
• Bed rest and activity restriction are not recommended — no proven benefit, and they raise VTE and bone-loss risk. Individual advice (e.g., pelvic rest) is from the provider

Heart disease — multidisciplinary cardio-obstetric care; continue safe drugs (e.g., beta blockers); warfarin is teratogenic — usually replaced by heparin (clients with mechanical heart valves: specialist decision); ACE inhibitors and ARBs are contraindicated; planned delivery, usually vaginal with epidural analgesia and an assisted second stage (avoid prolonged pushing).

Listed in priority order.

1. HG: restore fluid and electrolyte balance
   • IV access, isotonic fluids, potassium replacement, thiamine before dextrose
   • IV potassium safety: always diluted and given by infusion pump, never IV push or IM; common peripheral maximum 10 mEq/h per protocol; confirm adequate urine output first; continuous cardiac monitoring at higher rates; watch the site (pain, phlebitis)
   • Strict intake and output, daily weight, urine ketones
   • Monitor the IV site regularly — prolonged infusions and additives (potassium) irritate veins (phlebitis, infiltration)
   • Give antiemetics on schedule and monitor for sedation, EPS, and QT changes
   • Oral intake: rest the gut briefly if ordered, then start with small amounts of clear fluids and dry carbohydrates, advancing as tolerated
2. Heart disease: prevent decompensation
   • Rest in the lateral position, especially with dyspnea or fatigue (avoid supine); limit activity to tolerance but avoid complete immobility (VTE risk)
   • Monitor vital signs, SpO₂, lung sounds, weight, edema, and intake/output; careful IV fluid rates
   • After birth, close monitoring for at least 24–48 hours for fluid overload
3. Rh: confirm type and antibody status, give RhIG on time, document
4. Psychosocial support for all high-risk clients — open-ended questions ("Tell me how you are feeling about all this"), involve the support person, refer to social work or counseling

Nausea and HG

• Eat small, frequent, bland meals; dry crackers or toast before getting out of bed; separate liquids from solids; avoid fatty, spicy foods and strong odors
• Temporarily switch to a prenatal vitamin without iron or take folic acid alone if iron worsens nausea (per provider)
• Do not use any medicine, including over-the-counter pain relievers or herbal remedies, without the provider's approval
• Seek care for inability to keep fluids down for 24 hours, very dark or scant urine, dizziness, weight loss, or vomiting blood

Heart disease — report shortness of breath at rest, need for more pillows, palpitations, chest pain, or rapid weight gain

Rh — explain why RhIG is given at 28 weeks, after birth, and after bleeding or trauma; carry blood type information

Cervical insufficiency — report pelvic pressure, increased watery or mucous discharge, spotting, or cramping

• HG = persistent vomiting + weight loss (≥ 5%) + ketonuria + electrolyte imbalance (often hypokalemia)
• HG priority: fluids and electrolytes; I&O, daily weight, ketones; thiamine before dextrose
• First-line drug: pyridoxine ± doxylamine; ondansetron → QT; metoclopramide → EPS; promethazine → tissue injury
• HG with high BP or headache before 20 weeks → think molar pregnancy
• Heart disease: greatest risk at 28–32 weeks, labor, and early postpartum; rest side-lying; warfarin generally replaced by heparin (mechanical valves: specialist decision); ACE inhibitors/ARBs contraindicated
• RhIG for Rh-negative unsensitized: 28 weeks and within 72 hours after birth of an Rh-positive infant, plus after bleeding/procedures
• RhIG is not given to already sensitized clients
• Cervical insufficiency = painless second-trimester dilation → cerclage (12–14 weeks if history-based); bed rest is not recommended
• Adolescents: assess social support and emotional readiness
• TOLAC only where immediate cesarean is available