Background
In absence of ultrasound, symphysis-fundal height (SFH) can assess maternal-fetal well-being as it is associated with gestational age, fetal weight and amniotic fluid volume. However, other modifiers of SFH, including maternal infections, nutrient deficiencies and inflammation (MINDI), have not been widely explored.
Objectives
Our objectives were two-fold: 1) to assess prevalence of low SFH in indigenous Panamanian women using both PAHO and INTERGROWTH-21 standards and 2) to explore associations of SFH with maternal health indicators: infections (oral, skin, urogenital, nematode infections), nutrient deficiencies [protein and iron indicators (ferritin, serum iron, serum transferrin receptor, hepcidin), folate, vitamins A, D, B12] and inflammation [leukocytes, C-reactive protein, cytokines].
Methods
For this cross-sectional study, low-SFH-for-gestational-age was assessed using PAHO and INTERGROWTH < 10th centile in 174 women ≥16 weeks’ gestation. Bootstrapping selected MINDI variables for inclusion in multivariable fractional polynomial (MFP) logistic regressions for low-SFH. Associations of MINDI variables with hepcidin were also investigated.
Results
Prevalence of low-SFH was 8% using PAHO, but using INTERGROWTH, 50.6% had SFH < 10th centile, including 37.9% <3rd centile. Both PAHO-SFH < 10% and INTERGROWTH-SFH < 3rd centiles were associated with higher hepcidin (OR 1.12, p = 0.008 and OR = 3.04. p = 0.001, respectively) and with lower TNF-α (OR = 0.73, p = 0.012 and OR = 0.93, p = 0.015, respectively). Wood smoke exposure increased the odds of PAHO-SFH < 10th centile (OR = 1.19, p = 0.009) whereas higher BMI decreased the odds of INTERGROWTH-SFH < 3rd centile (OR = 0.87, p = 0.012). Lower pulse pressure (OR = 0.90, p = 0.009) and lower inflammatory responses [lower lymphocytes (OR = 0.21, p = 0.026), IL-17 (OR = 0.89, p = 0.011)] distinguished SFH < 3rd centile from SFH 3–10 using INTERGROWTH-21standards. The MFP regression for hepcidin controlling for SFH (Adj R2 = 0.40, p = 0.001) revealed associations with indicators of inflammation (CRP, p < 0.0001; IL-17, p = 0.012), acidic urinary pH (p = 0.008) and higher intake of supplements (p = 0.035).
Conclusion
Associations of low SFH with MINDI variables, including hepcidin, highlight its potential for early detection of multicausal in-utero growth faltering.
LAY SUMMARY
Symphysis-fundal height (SFH) is a measure of maternal-fetal well-being and is commonly used when sonography is not available to assess gestational age and the health of fetal-maternal unit. This simple non-invasive indicator uses a tape measure to measure the distance between the symphysis pubis and the highest point of the growing uterus. This distance was compared with two international standards: PAHO and INTERGROWTH. Using PAHO, 8% of women had low SFH (<10th centile for gestational age), but using INTERGROWTH standards, more than half of the women had low SFH with 37.5% having very low SFH (below the 3rd centile for gestational age). A SFH < 3rd centile was associated with higher hepcidin, a protein that decreases iron availability in blood as a defense against infections. In our study, low SFH was also associated with indicators of inflammation, malnutrition and a lower maternal blood pressure. This study supports the use of SFH in remote areas to identify pregnant women at risk of a poor pregnancy outcomes.
