Fetal distress is defined as a state of hypoxia and acidosis during pregnancy caused by depletion of oxygen and accumulation of carbon dioxide in the fetus. It can be caused by maternal factors like preeclampsia, anemia, bleeding, or infection, as well as placental or umbilical cord issues that obstruct blood flow. This leads to respiratory acidosis in the fetus and changes in fetal heart rate. Chronic fetal distress can cause intrauterine growth retardation. Clinical manifestations include meconium staining, abnormal fetal heart rate and movement patterns, and acidosis shown on fetal blood samples. Management involves addressing the cause, correcting acidosis, and potentially terminating the pregnancy through forceps delivery or c-section depending on severity of

1. Fetal
distress
LIN QI DE
2005.9.5

2. Definition
Fetal distress is defined as
depletion of oxygen and
accumulation of carbon
dioxide,leading to a state of
“hypoxia and acidosis ” during
intra-uterine life.

3. Etiology
Maternal factors
1) Microvascular ischaemia(PIH)
2) Low oxygen carried by RBC(severe
anemia)
3) Acute bleeding(placenta previa,
placental abruption)
4) Shock and acute infection
5) obstructed of Utero-placental blood flow

4. Etiology
Placenta 、 umbilical factors
1) Obstructed of umbilical blood flow
2) Dysfunction of placenta
3) Fetal factors
4) Malformations of cardiovascular system
5) Intrauterine infection

5. Pathogenesis
Hypoxia 、 accumulation of carbon dioxide
￬
Respiratory Acidosis
￬
Acute
FHR ￪ → FHR ￬→ FHR ￪
fetal
￬
distress
Intestinal peristalsis
￬
Relaxation of the anal sphincter
￬
Meconium aspiration
￬
Fetal or neonatal pneumonia

6. Pathogenesis
Chronic
Fetal
distress
IUGR
(intrauterine growth
retardation)

7. Clinical manifestation
Acute fetal distress
(1)FHR
FHR>180 beats/min (tachycardia)
<100 beats/min (bradycardia)
(LD) Repeated Late deceleration
Placenta dysfunction
(VD) Variable deceleration
Umbilical factors

8. Clinical manifestation
Acute fetal distress
(2) Meconium staining of the amniotic
fluid grade I 、 II 、 III
(3) Fetal movement
Frequently→decrease and weaken
(4) Acidosis
FBS (fetal blood sample)
pH<7.20
pO 2 <10mmHg (15~30mmHg)
CO >60mmHg (35~55mmHg)

9. Clinical manifestation
Chronic fetal distress
(1) Placental function
(24h E3<10mg or E/C<10)
(2) FHR
(3) BPS
(4) Fetal movement
(5) Amnioscopy

10. Management

Remove the induced factors actively

Correct the acidosis:

Terminate the pregnancy
5%NaHCO3 250ML
(1) FHR>160 or <120 bpm
meconium staining (II~III)
(2) Meconium staining grade III
amniotic fluid volume<2cm
(3) FHR<100 bpm continually

11. Management

Terminate the pregnancy
(4) Repeated LD and severe VD
LD
(5) Baseline variability disappear with
(6) FBS pH<7.20
Forceps delivery
Caesarean section