Determining how long a baby stayed inside the womb is a core skill for midwives practicing in Nigeria. Gestational age assessment helps us separate babies born too early from those who arrived on time but are too small for their dates. We rely on two main methods: looking at the mother's last menstrual period and early ultrasound scans, or examining the baby's body right after birth. When records are missing or unreliable—a common situation in many rural Nigerian primary health centers—physical and neurological examinations become our primary tools. Knowing the exact gestational age guides our immediate care, helps us spot prematurity complications like breathing trouble, and ensures the baby receives appropriate feeding support.
The New Ballard Score is an expanded tool used to estimate gestational age from 20 weeks up to 44 weeks. It improved upon earlier scoring systems by including extremely premature infants, going down to 20 weeks gestation. The system is split into two distinct categories: neuromuscular maturity and physical maturity. Each category contains six specific criteria scored from -1 to 5. Midwives add the scores from both sections together to find a final numerical total, which corresponds directly to a specific gestational age in weeks on the scoring chart. Performing this assessment requires patience and should ideally be done within the first 12 hours of life for preterm infants, as neurological tone changes rapidly over the first few days.
Neuromuscular criteria measure how the baby's nervous system controls muscle tone. As a fetus matures, muscle tone shifts from extreme flexibility to strong flexion.
Physical maturity criteria evaluate anatomical changes that occur as pregnancy progresses. Unlike neurological signs, physical features change more slowly over days, giving midwives a slightly wider window for evaluation.
Calculating the final Ballard score requires careful attention to detail. Midwives examine each of the 12 criteria and assign a score ranging from -1 to 5 based on the standardized scoring chart printed on the assessment tool. After grading all six neuromuscular and six physical items, the midwife adds the individual numbers together to get a composite score. This total score—which can range from -10 to 50—is then located on the reference table to find the corresponding gestational age in weeks. A common mistake in busy labour wards is rushing the physical inspection or guessing scores without checking the criteria guide. Taking time to reference the chart properly ensures accurate classification, which directly impacts the baby's ongoing care plan.
Once the gestational age is calculated, the midwife classifies the newborn into a standard category: preterm (before 37 completed weeks), term (between 37 and 41 completed weeks), or post-term (42 weeks and beyond). This classification is then combined with birth weight percentiles to determine if the baby is appropriate, small, or large for gestational age. For example, a baby born at 36 weeks weighing 1.8 kg requires monitoring for hypothermia, hypoglycemia, and jaundice. Midwives use these insights to educate mothers on proper thermal care, encourage early initiation of breastfeeding, and decide when the newborn is ready for discharge from the facility.