Fetal assessment and monitoring are critical components of the preoperative evaluation for pregnant patients. The objective is to establish fetal well-being and identify any conditions that might increase the risk of adverse outcomes during surgery. Ultrasound is the primary tool for fetal assessment and should be used to confirm gestational age, evaluate fetal growth and amniotic fluid volume, and assess placental location. If there are concerns about fetal growth restriction or placental insufficiency, Doppler studies of the umbilical artery may be necessary to evaluate fetal blood flow.
Non-stress testing (NST) or biophysical profile (BPP) may also be used to assess fetal well-being, particularly in the later stages of pregnancy. An NST monitors fetal heart rate patterns in response to fetal movements, providing indirect information on the fetus's oxygenation status. The BPP combines NST results with ultrasound assessments of fetal movement, tone, breathing, and amniotic fluid volume, offering a comprehensive evaluation of fetal health. Additional fetal monitoring, such as electronic fetal heart rate (FHR) monitoring during surgery, may be considered depending on the gestational age and clinical scenario. This monitoring helps detect early signs of fetal distress, allowing timely intervention to optimize maternal hemodynamics and oxygenation.
If the fetus is viable (typically around 24 weeks gestation), preparations for potential delivery should be made, including having neonatal resuscitation equipment and personnel available in case intraoperative complications necessitate an emergent delivery. A multidisciplinary team approach involving obstetricians, anesthesia providers, neonatologists, and surgeons is essential to coordinate care and ensure that appropriate monitoring and intervention strategies are in place to protect both maternal and fetal health.
| Tool or step | What it evaluates | When used |
|---|---|---|
| Ultrasound | Confirms gestational age; evaluates fetal growth, amniotic fluid volume and placental location | Primary tool for fetal assessment |
| Umbilical artery Doppler | Fetal blood flow | When there are concerns about fetal growth restriction or placental insufficiency |
| Non-stress test | Fetal heart rate patterns in response to fetal movement, giving indirect information on oxygenation status | Particularly in the later stages of pregnancy |
| Biophysical profile | Combines the non-stress test with ultrasound assessment of fetal movement, tone, breathing and amniotic fluid volume | Particularly in the later stages of pregnancy, for a comprehensive evaluation |
| Intraoperative electronic fetal heart rate monitoring | Early signs of fetal distress, prompting optimization of maternal hemodynamics and oxygenation | Depending on gestational age and clinical scenario |
| Delivery preparation | Neonatal resuscitation equipment and personnel on hand for emergent delivery | Once the fetus is viable, typically around 24 weeks gestation |
