Doctors caring for very premature babies (born before 28 weeks) often worry about weak bones, which can lead to fractures. Researchers in Saudi Arabia studied 484 premature babies to find the best blood tests for catching bone weakness early. They discovered that measuring a hormone called PTH in the blood was the most accurate way to predict which babies had weak bones on X-rays. This finding could help doctors start treatments sooner to strengthen babies’ bones and prevent injuries.

The Quick Take

  • What they studied: Which blood tests best predict weak bones in very premature babies
  • Who participated: 484 premature babies born before 28 weeks of pregnancy or weighing less than 1000 grams, treated at a major hospital in Saudi Arabia between 2017 and 2024
  • Key finding: A blood test measuring PTH (a bone-related hormone) was the most accurate predictor of weak bones, correctly identifying the problem about 79% of the time
  • What it means for you: If you have a very premature baby, doctors may use this blood test to catch bone weakness early and start treatments to prevent fractures, though more research is needed to confirm these results in other hospitals

The Research Details

Researchers looked back at medical records from 484 premature babies treated between 2017 and 2024 at a hospital in Saudi Arabia. All these babies were part of a special bone health program designed to monitor and protect their bones. The doctors collected blood samples from the babies and measured different substances related to bone health, including PTH, alkaline phosphatase (an enzyme), phosphate, and vitamin D. They also took X-rays of the babies’ bones and had a specialist radiologist (a doctor trained to read X-rays) look at the images to see which babies had weak bones. The radiologist didn’t know the babies’ blood test results when looking at the X-rays, which helps prevent bias.

The researchers then used statistical methods to figure out which blood tests were best at predicting weak bones. They looked at how accurate each test was and found the best cut-off numbers that doctors could use to identify at-risk babies.

This research approach is important because it helps doctors find the simplest, most reliable way to spot bone problems in premature babies before serious complications happen. Premature babies are at high risk for weak bones because they miss important months in the womb when bones normally get stronger. By identifying the best blood test, doctors can start treatments earlier and potentially prevent fractures that could harm these vulnerable babies.

This study has good strengths: it included a large number of babies (484), used a standardized program for bone care, and had a radiologist who didn’t know the blood test results when reading X-rays. However, the study only looked at one hospital in Saudi Arabia, so results might be different in other countries or hospitals. The study is also retrospective, meaning researchers looked back at past records rather than following babies forward in time, which can sometimes miss important details.

What the Results Show

The researchers found that weak bones were common in these premature babies. Most babies (77%) had low phosphate levels in their blood, and about 21% had high alkaline phosphatase levels. When comparing blood tests to X-ray findings, PTH (parathyroid hormone) was the most accurate test, correctly identifying weak bones about 79% of the time. The best cut-off number for PTH was 17.6 pmol/L—babies with higher levels were more likely to have weak bones on X-rays.

Alkaline phosphatase was the second-best test, correctly identifying weak bones about 66% of the time, while phosphate levels were less helpful for prediction. Vitamin D levels were measured but were not as useful for predicting bone weakness in this group of babies.

These findings suggest that PTH should be part of routine blood testing for premature babies, possibly combined with alkaline phosphatase and phosphate measurements, to catch bone problems early.

The study found that biochemical abnormalities (unusual blood test results) were very common in premature babies, with most showing low phosphate levels. This suggests that premature babies routinely need mineral supplementation to support bone development. The combination of multiple blood tests together may provide better prediction than any single test alone, though the study didn’t fully explore this.

Previous research has suggested that premature babies often develop weak bones, but this study provides clearer evidence about which specific blood tests work best for early detection. The finding that PTH is more accurate than alkaline phosphatase is somewhat different from what some older studies suggested, possibly because this research used a more systematic approach and larger group of babies.

The study only included babies from one hospital in Saudi Arabia, so results might not apply to premature babies in other countries with different nutrition, sunlight exposure, or medical practices. The study looked backward at past records rather than following babies forward, which means some information might be missing or recorded differently. The study didn’t follow babies long-term to see if identifying weak bones early actually prevented fractures or improved outcomes. Additionally, the study excluded babies who died very early or had genetic bone diseases, so results may not apply to the sickest premature babies.

The Bottom Line

Based on moderate evidence, doctors caring for very premature babies should consider measuring PTH levels as part of routine bone health screening. This should be combined with alkaline phosphatase and phosphate measurements. Babies with elevated PTH levels may benefit from earlier mineral supplementation or other bone-strengthening treatments. However, these recommendations should be confirmed with additional studies in different hospitals and countries before becoming standard practice everywhere.

Parents of very premature babies (born before 28 weeks or weighing less than 1000 grams) should care about this research, as it could lead to better ways of protecting their baby’s bones. Neonatal doctors and nurses should also pay attention, as it provides guidance on which blood tests to prioritize. This research is less relevant for babies born at full term or with normal birth weights, as they have much lower risk of bone weakness.

Blood test results can be available within days, allowing doctors to start treatments quickly if needed. However, improvements in bone strength typically take weeks to months to develop. Parents shouldn’t expect to see dramatic changes immediately, but early detection and treatment may prevent fractures that could occur months later.

Want to Apply This Research?

  • Track your premature baby’s PTH, alkaline phosphatase, and phosphate blood test results at each measurement (typically every 2-4 weeks in the NICU). Record the dates, values, and whether the baby received mineral supplements or other bone-health treatments.
  • Work with your baby’s medical team to ensure PTH testing is included in routine blood work. Ask doctors to explain what the results mean and what treatments are recommended. Keep a record of all bone-related blood tests and X-ray results to share with follow-up doctors after discharge from the hospital.
  • Create a timeline tracking PTH levels from birth through discharge and into early childhood follow-up visits. Note any treatments given (mineral supplements, vitamin D, etc.) and any bone-related complications. This information helps doctors see patterns and adjust care as needed.

This research provides information about blood tests for detecting weak bones in premature babies but should not replace medical advice from your baby’s doctors. Every baby is different, and treatment decisions should be made by your medical team based on your baby’s individual condition, blood tests, and X-ray results. If you have concerns about your premature baby’s bone health, discuss them with your neonatologist or pediatrician. This study was conducted at one hospital and may not apply to all settings or populations.