What is the management plan for inconsistent fundal height measurements with expected gestational age, referred to as 'fundal heights umbilical'?

From the Guidelines

When fundal height measurements are inconsistent with gestational age, a systematic evaluation is necessary to determine the cause of the discrepancy, and the management plan should involve an ultrasound to assess fetal growth, amniotic fluid volume, and placental location, as well as serial umbilical artery Doppler assessments to monitor for deterioration, as recommended by the Society for Maternal-Fetal Medicine 1. The evaluation should consider various conditions that may affect pregnancy outcomes, including intrauterine growth restriction (IUGR), oligohydramnios, or abnormal fetal position if measurements are small for gestational age, and conditions such as polyhydramnios, multiple gestation, macrosomia, or uterine fibroids if measurements are large for gestational age. Key components of the management plan include:

• Serial ultrasounds to track growth, typically every 3-4 weeks
• Antenatal testing, such as non-stress tests or biophysical profiles, if IUGR is suspected
• Umbilical artery Doppler assessments to monitor for deterioration, with weekly evaluations for pregnancies with severe fetal growth restriction or decreased end-diastolic velocity 1
• Consideration of delivery at 37 weeks of gestation for pregnancies with fetal growth restriction and an umbilical artery Doppler waveform with decreased diastolic flow but without absent/reversed end-diastolic velocity or with severe fetal growth restriction with estimated fetal weight less than the third percentile 1 The use of population-based fetal growth references, such as Hadlock, is recommended to determine fetal weight percentiles 1, and the cerebroplacental ratio may be a useful predictor of adverse outcome among fetuses with FGR, although its value as a stand-alone test is still being researched 1. It is essential to individualize management based on the specific gestational age, fetal well-being, and other sonographic findings, including the presence of structural defects, chromosomal abnormalities, and Doppler abnormalities 1.

From the Research

Fundal Heights Umbilical Measurement and Management

• The management plan for inconsistent fundal height measurements with expected gestational age involves a combination of fundal height and ultrasound to predict small for gestational age at birth 2.
• A longitudinal fundal height calculator can be used to improve the identification of small for gestational age birth weight, while reducing the number of triggered ultrasounds 2.
• The American College of Obstetricians and Gynecologists (ACOG) and other medical societies recommend serial symphysis fundal height measurement for low-risk pregnancies, and increased sonographic surveillance for high-risk pregnancies 3.

Diagnostic Criteria and Testing

• The diagnostic criteria for fetal growth restriction (FGR) and small-for-gestational-age fetuses vary among medical societies, but most agree on the importance of early universal risk stratification for FGR 3.
• Umbilical artery Doppler assessment is required to further guide management after FGR diagnosis, and amniotic fluid volume evaluation is also recommended by some medical societies 3.
• Prenatal diagnostic testing is supported by some medical societies in cases of early, severe FGR or FGR accompanied by structural abnormalities 3.

Screening Tools and Accuracy

• Fundal height is a useful screening tool for fetal growth, but its sensitivity is less than 35% for detecting abnormal intrauterine growth, although specificity is more ideal at >90% 4.
• The accuracy of symphysis fundal height (SFH) for gestational age estimation is poor, with a mean bias of -14.0 days compared to ultrasound-confirmed GA, and 95% limits of agreement of ±42.8 days 5.
• Increasing access to quality ultrasonography early in pregnancy is prioritized to improve gestational age assessment in low- and middle-income countries 5.

Relationship with Preeclampsia

• There is a strong but complex relationship between fetal growth restriction and preeclampsia, with different placental and cardiovascular mechanisms underlying this trend 6.
• The incidence of preeclampsia decreases dramatically from early preterm fetal growth restriction to late preterm and term fetal growth restriction 6.
• Current strategies for first trimester screening of placental dysfunction do not perform well for late-onset fetal growth restriction, with decreasing sensitivity for small-for-gestational-age newborns delivered at later gestational ages 6.