Uterine hypoplasia

Disease Description (Causes and Symptoms)

• Definition: A condition in which the estimated fetal weight (ultrasound EFW) is below the 10th percentile compared with the average for the same gestational age (generally designated as intrauterine growth restriction, IUGR, or FGR).
• Main pathophysiology: Reduced fetal oxygen and nutrient supply due to maternal–placental circulation insufficiency (reduced placental function) → chronic hypoxia and growth restriction. In severe cases, the fetus reduces peripheral blood flow and redistributes blood flow to the brain (brain-sparing), resulting in disproportionate growth. Reduced amniotic fluid volume (oligohydramnios) occurs due to decreased fetal urine output.
• Main causes
  • Maternal factors: Advanced maternal age/low body weight, chronic hypertension·kidney disease, gestational hypertension·preeclampsia, chronic nutritional deficiency, smoking·alcohol use·medication use, anemia, poor diabetes control, etc.
  • Placental factors: Placental abnormalities, placental insufficiency (reduced blood flow), placenta previa·premature placental abruption, etc.
  • Fetal factors: Chromosomal abnormalities, infection (e.g., CMV), multiple gestation, severe umbilical cord problems, etc.
• Symptoms (clinical signs)
  • Clinically, the uterine fundus is smaller than expected for the gestational age (the fetus is small)
  • Decreased fetal movement (changes in fetal movement perceived by the mother)
  • Reduced amniotic fluid volume and low estimated fetal weight on ultrasound

Treatment Methods

• General principles: Evaluate and correct the cause and decide between conservative management and delivery according to fetal status and gestational age
• Monitoring and diagnostic tests
  • Periodic ultrasound (growth curve, estimated weight, amniotic fluid volume) — usually at 1-week intervals or more frequently depending on the condition
  • Doppler studies (umbilical artery, middle cerebral artery, uterine artery) — absent end-diastolic flow/reversed flow in the umbilical artery is a warning sign
  • Nonstress test (NST), biophysical profile (BPP)
• Conservative treatment
  • Correction of the maternal condition: Treatment and optimization of hypertension·anemia·nutritional deficiency·diabetes
  • Elimination of risk factors: Smoking cessation·alcohol cessation·discontinuation of medications, nutritional supplementation
  • Hospital observation (in severe cases), periodic fetal monitoring (NST/BPP/Doppler)
  • Glucocorticoids (to induce fetal lung maturation): Administration may be considered when preterm birth is possible and the gestational age is near the relevant period (generally 24–34 weeks)
  • Transfer to an appropriate facility and preparation for the NICU as needed, including promotion of fetal maturation
• Decision on delivery (induction/cesarean section)
  • The timing of delivery is determined according to gestational age and fetal status (Doppler abnormalities, abnormal NST, severely reduced amniotic fluid volume, etc.)
  • Delivery is recommended in cases of fetal distress (irreversible Doppler abnormalities, repeated nonreassuring tests, etc.)
  • The delivery method depends on obstetric factors such as fetal status, pelvic size, and history of cesarean section (an emergency cesarean section may be more likely)
• Medication/procedure-specific considerations
  • There are no medications that directly promote fetal growth. Treatment of maternal diseases (hypertension, anemia, etc.) takes priority.
  • Maternal oxygen therapy has limited evidence and is not routinely recommended.
• Precautions (risk of complications and self-management)
  • Severe IUGR increases the risk of fetal death, hypoxia/acidosis during delivery, preterm birth, and hypoglycemia·hypothermia·infection after low birth weight
  • During hospital observation, immediate emergency evaluation is needed if decreased fetal movement, vaginal bleeding, leakage of amniotic fluid, or severe headache·visual disturbance (suspicious for preeclampsia) occurs

Checklist Before an Outpatient Visit (Including Preparation Items and Example Questions)

• Items to bring
  • List of currently used medications·supplements (including doses and duration of use)
  • Previous obstetric and gynecologic records (previous deliveries, miscarriages, history of cesarean section) and medical documentation of chronic diseases (hypertension, diabetes, kidney disease, etc.)
  • Previous ultrasound·test results (photos·reports if possible)
  • Record of recent weight changes and diet·smoking·alcohol·medication history
  • Record of changes in fetal movement (when it began to decrease and how much it has decreased)
• Symptoms to inform the medical staff of in advance when visiting the outpatient clinic
  • Decreased fetal movement, vaginal bleeding, abdominal pain, leakage of amniotic fluid, severe headache·visual disturbance, etc.

Examples of General Questions to Ask the Doctor

• "What percentile is the fetus's current estimated weight compared with the gestational age?"
• "Which tests will be used for monitoring, and how often will they be performed?"
• "What are the side effects of this medication (the prescribed medication), and what effects can it have on the fetus?"
• "How is the timing of delivery determined? How likely is preterm delivery?"
• "What is the prognosis? What are the risks of long-term effects (such as neurodevelopmental effects)?"

Examples of Disease-Specific Questions

• "Are there signs of reversed flow or absent end-diastolic flow on the umbilical artery Doppler? If so, should immediate delivery be considered?"
• "What is the current amniotic fluid volume (AFI or MVP)? How will changes in amniotic fluid volume affect the decision about delivery?"

(Urgent notice) If fetal movement suddenly decreases or vaginal bleeding·severe abdominal pain·leakage of amniotic fluid·symptoms of severe hypertension occur, go immediately to the emergency room or the obstetrics and gynecology department in charge.