EFFECTS OF MATERNAL HYPOXIA ON FETAL OXYGENATION AND FETAL ADAPTIVE PHYSIOLOGICAL RESPONSES DURING PREGNANCY

Abstract

Background: The condition of maternal hypoxia in pregnancy is a major clinical disorder that may negatively impact the fetal oxygenation and result in compensatory physiological adjustments to the fetus. The low level of maternal oxygen can lead to the impaired placental functioning, and poor neonatal outcomes, especially in the resource constrained environment where anemia and respiratory diseases are prevalent.

Objective: To evaluate the effects of maternal hypoxia on fetal oxygenation and fetal adaptive physiological responses during pregnancy.

Methods: The presented descriptive cross-sectional research was carried out at Mardan Medical Complex/ Bacha Khan Medical College Mardan between January 2024 and January 2025. Non-probability consecutive sampling was used to include 72 pregnant women whose gestational age was 24 weeks and above. Pulse oximetry was used to measure maternal oxygen saturation, and hypoxia was determined as SpO 2 less than 90%. Fetal oxygenation was measured with umbilical cord blood gas analysis and placental and fetal circulation was measured with Doppler ultrasound. Neonatal outcomes in terms of birth weight, APGAR score, and NICU admission were captured. The SPSS version 25 was used to analyse the data and p ≤0.05 was regarded as statistically significant.

Results: Maternal hypoxia was observed in 31.9% of participants and was significantly associated with maternal anemia (p = 0.001), respiratory illness (p = 0.006), and smoking exposure (p = 0.01). Hypoxic pregnancies demonstrated significantly impaired fetal oxygenation, including increased acidosis (60.9% vs 16.3%, p < 0.001), low cord pO₂ (69.6% vs 16.3%, p < 0.001), and elevated lactate levels (p = 0.001). Fetal adaptive responses such as brain-sparing effect were significantly higher in hypoxic cases (69.6% vs 18.4%, p < 0.001). Adverse neonatal outcomes, including low birth weight (p = 0.01), low APGAR score (p = 0.01), and increased NICU admissions (p = 0.004), were significantly associated with maternal hypoxia.

Conclusion: Maternal hypoxia significantly compromises fetal oxygenation and leads to adaptive physiological changes and adverse neonatal outcomes. Early detection and management of maternal hypoxia are essential to improve maternal and fetal health outcomes.