Fetal scalp electrodes (FSE) are commonly used to obtain more accurate fetal monitoring as an alternative to external Doppler. An estimated 22% of deliveries involve placement of an FSE [1]. The FSE is especially useful for continuous monitoring in cases of non-reassuring fetal heart tones or large body habitus. Contraindications for FSE include fetal facial or brow presentation, intact fetal membranes, placenta previa, infection with human immunodeficiency virus (HIV), active herpetic lesions, and other infectious risks to the fetus [3]. The distal electrode with a spiral wire tip must be screwed into and penetrate the scalp. The most frequently reported complications of FSE use include cellulitis, abscess, sepsis, and cephalohematoma and meningitis in the fetus, and endometritis, chorioamnionitis, and vaginal or cervical trauma in the mother [1, 2]. Another possible complication is placement of the FSE in the periorbital region, which may result in intraocular injury [4]. We describe a patient delivered in the cephalic left occipital anterior position with an FSE embedded in the left upper eyelid during delivery who fortunately recovered without complication. Periorbital edema in the neonate likely protected the infant from complete eyelid penetration, globe injury, or deeper ocular damage. However, Ophthalmology should be consulted if the FSE is embedded in the periocular region or if there is concern for periocular injury (e.g. laceration or ocular swelling/redness) caused by FSE misplacement, for thorough ophthalmic examination to rule out ocular injury.
Facial or brow presentation of the fetus also increases the likelihood of ocular complications secondary to FSE placement. Risk factors for facial and brow presentations include multiparity and previous Caesarean section [5]. Lower abdominal muscle tone in multiparous patients may lead to pendulum swinging of the fetus' abdomen forward, extending the neck and increasing the likelihood of facial or brow presentation [6]. Delayed engagement of the fetal head and maternal pelvis in multiparous women may also contribute to higher rates of facial or brow presentation. It has been suggested that previous Caesarean section may cause lower uterine segment contractile dysfunction that limits head flexion during delivery [5]. For patients with multiple risk factors for facial or brow presentation, fetal monitoring is ideally performed with an external probe. However, previous studies suggest there is a high prevalence of severe variable decelerations and late decelerations associated with facial presentation that may necessitate an internal device [7, 8]. As such, for patients at greater risk for facial or brow presentation and requiring internal monitoring, clinicians should verify vertex position immediately prior to FSE placement to reduce the likelihood of FSE misplacement, as most cases of facial and brow presentation are not diagnosed until the second stage of labor [9]. In the presented patient case, vertex position had been visualized on ultrasound prior to induction, but review of the medical record did not document that an ultrasound was repeated before FSE placement. If internal fetal monitoring is required for cases of facial or brow presentation, extreme caution should be taken to apply the FSE over forehead, mandible, or other bony structure to avoid injury.
Two previous cases of ocular adnexal injury by an FSE have been reported in ophthalmology literature. The first involved a neonate with an FSE that was inadvertently placed on the left upper eyelid during labor and avulsed by its own weight during caesarean section; further ocular examination identified superficial eyelid lacerations but no globe injury [10]. The second report detailed a case in which the FSE was placed on the right eye, and further examination found that the FSE had penetrated the inferior sclera and torn the peripheral retina [4]. The patient eventually developed lens dislocation and required complete removal of the lens and capsule and anterior vitrectomy three years after initial injury; at eight years of age, visual acuity was 20/200 with a contact lens in the injured eye and 20/20 without correction in the contralateral eye [4].
In conclusion, facial presentation occurs in 1 in 600 births, and brow presentation has a prevalence of 1 in 500-4000 births [11]. Though uncommon, facial or brow malpresentation can increase the risk for misplacement of the FSE. This case report highlights the importance of confirming the fetal position prior to placement of the FSE. If there is suspicion for facial or brow presentation of the fetus, clinicians should avoid using an FSE, if possible, or take extreme care in the placement. Ophthalmology consult is warranted in the event of periorbital injury caused by FSE placement to exclude deeper ocular injury.
