Monitoring Baby's Growth Through Medical Tests

Monitoring the baby's growth throughout pregnancy provides valuable information about fetal well-being and the adequacy of the placental supply of oxygen and nutrients. Babies who are growing too slowly may be at risk of complications during labour and the neonatal period, while those growing too rapidly may be associated with maternal conditions such as gestational diabetes. Regular growth assessment is therefore a critical component of prenatal care.

In India, where the incidence of low birth weight remains significant, monitoring fetal growth helps identify at-risk babies early, allowing for timely intervention. Obstetricians in Visakhapatnam utilise a combination of clinical assessments and diagnostic tests to track growth trajectories and ensure that each baby is developing within expected parameters.

Growth monitoring is not a one-time assessment but a continuous process throughout pregnancy. Serial measurements plotted on growth charts over time are more informative than single measurements, as they reveal trends that indicate whether growth is progressing normally, slowing, or accelerating.

At each prenatal visit from approximately 24 weeks onwards, the doctor measures the fundal height, which is the distance from the pubic bone to the top of the uterus. This simple measurement, recorded in centimetres, roughly corresponds to the gestational age in weeks. A fundal height that is significantly smaller or larger than expected may prompt further investigation.

The doctor also assesses the baby's position, listens to the fetal heartbeat, and asks the mother about fetal movements. These clinical observations, combined with the mother's own awareness of her baby's activity patterns, provide a baseline assessment of fetal well-being that complements the information obtained from tests.

Ultrasound is the primary diagnostic tool for assessing fetal growth in detail. During a growth scan, the sonographer measures the baby's head circumference, biparietal diameter, abdominal circumference, and femur length. These measurements are used to calculate an estimated fetal weight, which is then plotted on standardised growth charts for the gestational age.

Serial growth scans, typically performed every two to four weeks in monitored pregnancies, allow the doctor to track the growth trajectory. A baby who was previously growing along the 50th percentile but has dropped to the 10th percentile may have growth restriction, even if the actual weight is still within the normal range. It is the trend that matters most.

Growth scans also assess the volume of amniotic fluid, the condition of the placenta, and the baby's overall proportions. Discordant growth between the head and body may suggest asymmetrical growth restriction, while symmetrically small measurements may indicate a constitutionally small baby or an early onset growth problem.

Doppler ultrasound measures blood flow velocity in the umbilical artery, middle cerebral artery, and other fetal and maternal vessels. In the context of growth monitoring, umbilical artery Doppler is the most commonly used, as it reflects placental function. Normal blood flow patterns indicate adequate placental support, while abnormal patterns suggest compromised placental function.

Absent or reversed end-diastolic flow in the umbilical artery is a concerning finding that indicates severe placental insufficiency. This finding often influences the timing of delivery, as it suggests that the baby may not tolerate continued time in the womb. Doppler studies are invaluable in managing the balance between the risks of prematurity and the risks of an adverse intrauterine environment.

The non-stress test monitors the baby's heart rate in response to its own movements. A reactive test, where the heart rate increases appropriately with movement, is reassuring. A non-reactive test may prompt further evaluation with a biophysical profile, which combines ultrasound assessment of fetal movement, tone, breathing, and amniotic fluid with the non-stress test result.

These tests are typically performed in the third trimester, particularly for pregnancies identified as high-risk or where growth concerns have been raised. They provide a snapshot of the baby's current condition and help the doctor make decisions about the ongoing management plan, including whether continued monitoring is appropriate or whether delivery should be considered.

When growth monitoring identifies concerns, the doctor develops a management plan tailored to the specific findings. Mild growth restriction with normal Doppler and adequate amniotic fluid may be managed with increased surveillance and maternal rest. More significant findings may require hospitalisation, antenatal corticosteroids for lung maturity, and planning for early delivery.

Open communication between the mother and the medical team ensures that monitoring results are understood and that decisions are made collaboratively. Mothers should ask questions about what the results mean, what changes to the care plan are being made, and what signs they should watch for at home. This partnership between patient and provider is essential for achieving the best possible outcome for the baby.