What are the causes of fetal hypoxia?

Mar 18, 2025 Source: Cainiu Health

Dr. Zhang Lu

Introduction

Under normal circumstances, fetal hypoxia may be caused by factors such as the umbilical cord, amniotic fluid, anemia, pregnancy-induced hypertension, or placental insufficiency. Symptomatic management is usually required through general treatment, medication, and other methods. Pregnant women should attend regular prenatal checkups at the hospital to monitor their own health status and the development of the fetus.

Generally, fetal hypoxia may be caused by factors such as umbilical cord abnormalities, amniotic fluid issues, maternal anemia, gestational hypertension, or placental insufficiency. Symptomatic management usually involves general supportive care and medication therapy. If symptoms are severe, prompt medical attention is recommended, with treatment following medical guidance. Detailed explanations are as follows:

1. Umbilical Cord Factors

Abnormal umbilical cord length, nuchal cords (cord around the fetal neck), or cord torsion may impair blood flow through the umbilical cord, hindering oxygen delivery to the fetus and resulting in fetal hypoxia. This may manifest as abnormal fetal movements, such as decreased or absent fetal movement. Pregnant women should learn how to correctly monitor fetal movements and promptly seek medical attention when abnormalities are detected.

2. Amniotic Fluid Factors

Oligohydramnios (low amniotic fluid) can restrict fetal movement space, impair fetal respiratory movements, and interfere with substance exchange between the placenta and fetus, thereby reducing oxygen supply to the fetus. It may be accompanied by decreased fetal activity and increased uterine sensitivity. Pregnant women are advised to undergo regular prenatal checkups to monitor amniotic fluid levels. In cases of oligohydramnios, amniotic fluid volume can be increased through procedures such as amnioinfusion.

3. Anemia

Poor nutrition, excessive blood loss, or impaired hematopoietic function can lead to maternal anemia. Anemia reduces the number of red blood cells or hemoglobin levels in the mother's blood, impairing oxygen transport capacity and thus affecting oxygen supply to the fetus. Symptoms may include fatigue, pallor, and weakness. It is recommended to follow medical advice to use medications such as ferrous sulfate sustained-release tablets, iron(II) fumarate tablets, or ammonium ferric citrate vitamin B1 syrup II to alleviate symptoms.

4. Gestational Hypertension

If a pregnant woman has a family history of hypertension or abnormal placental implantation, she may develop gestational hypertension. Hypertension during pregnancy is a common complication that may cause placental vascular sclerosis, impairing blood flow and leading to fetal hypoxia due to insufficient oxygen supply. Symptoms may include headache, visual disturbances, nausea, and vomiting. Pregnant women should follow medical guidance for treatment with medications such as labetalol hydrochloride tablets, nifedipine tablets, or methyldopa tablets.

5. Placental Insufficiency

As pregnancy progresses, the placenta may age or develop abnormally, impairing its normal function of oxygen and nutrient exchange, thereby reducing oxygen supply to the fetus and causing hypoxia. This is often accompanied by symptoms such as decreased fetal movement and oligohydramnios. Close monitoring of fetal heart rate changes is necessary, and cesarean section or induction of labor may be required to terminate the pregnancy promptly if indicated.

Pregnant women should attend regular prenatal checkups at the hospital to monitor maternal health and fetal development.

References

[1] Wei Qiping. Correlation between ultrasound monitoring of middle cerebral artery and umbilical artery parameters in late pregnancy and adverse perinatal outcomes. Modern Diagnosis and Treatment, 2023, 34(10): 1506-1508.

[2] Zhang Hongwei. Clinical significance of middle cerebral artery and umbilical artery resistance indices measured by color Doppler ultrasound in diagnosing fetal hypoxia. China Practical Medicine, 2023, 18(17): 60-62.

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