What Is a Fetal Pulse Oximeter?

The term fetal pulse oximeter refers to a medical device that non-invasively measures the oxygen saturation (SpO2) in a fetus or newborn. The device differs slightly in its attachment method depending on whether the medical professional uses it to measure a fetus’ oxygen saturation or a newborn’s.

It provides nearly as much information as an arterial blood gas examination to read peripheral oxygen saturation. It does so without risk to the fetus or child.

Measuring Oxygen Saturation Using Pulse Oximetry

In children and adults, a pulse oximeter uses a sensor attached to a thin part of the individual’s body, typically their earlobe or fingertip, to measure or monitor oxygen saturation. In an infant, the oximeter fits onto the child’s foot.

In the case of a fetus, fetal pulse oximetry uses an oximeter that features a probe that rests on the baby’s head. The healthcare provider inserts the fetal pulse oximetry sensors through the dilated cervix during the mother-to-be’s labor. Due to the tiny size of an oximeter, this probe and device don’t get in the way of the mother-to-be’s mobility while conducting real-time fetal monitoring.

How a Fetal Pulse Oximeter Works

These fetal monitoring devices use two modes of application: transmissive and reflection pulse oximetry. The fetal oximetry measuring activity works differently depending on the mode the device uses.

Transmissive Pulse Oximetry

Most devices use the transmissive mode of application. In transmissive mode, the oximeter sends two light wavelengths to a photodetector via the earlobe, foot, fingertip, or head. By pulsating arterial blood with these wavelengths of light, it measures their absorbances but excludes that of the epidermis, muscle mass, bone tissue, venous blood, and fat. (Doctors typically have the patient remove any nail polish in children and adults since it can block the light wavelengths causing issues in accurate measurements.)

Reflection Pulse Oximetry

The lesser-known reflection pulse oximetry uses the feet, chest, or forehead for its measurement. It can lead to erroneous readings due to clumping of the venous blood in the head. This impaired return to the heart can trigger venous and arterial pulses in the forehead, which results in incorrect O2 readings. Inaccurate readings can also arise during anesthesia using mechanical ventilation, endotracheal intubation, or when the patient lies in the Trendelenburg position—supine with the feet above the head.

Choosing a Fetal Oximeter

When shopping for your medical practice, clinic, or hospital, keep in mind a few considerations. Suppose you work in purchasing and procurement, and your physicians or nursing staff don’t actively participate in small-dollar purchases. In that case, you may need to choose the oximeters yourself without expertise in fetal electrocardiography (fetal ECG) or fetal oximetry.

Medical personnel often use the nickname ox meter for this fetal ECG device. Some professional publications even use this cutesy name for the device. 

• Your doctors require both transmissive and reflection oximeters. A fetal pulse oximeter falls under the reflection mode classification.
• Don’t let manufacturers’ design choices for infants and children put you off from their products. Some of the top-quality oximeters for children feature Disney characters in the design. This entertains the child and makes the equipment less scary.
• Consider your hospital or medical facility’s computer systems before purchasing. Most of these devices now come with software that helps track patient information.
• Some fetal pulse ox meters come with accessories, including batteries. This lets the medical professional use them right out of the box. These kits come in handy while in the field, for example, when responding to an emergency outside the hospital. This might occur when organizations and hospitals set up triage outposts in cases of a natural hazard, such as a hurricane.
• Most medical supply websites offer verified reviews from purchasers. Reference these before purchasing and prioritize the choices of facilities the same size and composition as yours.

Take advantage of bulk discounts. Fetal pulse oximeters cost very little, especially compared to typical medical equipment. A well-made ox meter might cost just $19.95. Due to these low prices, many medical supply stores offer bulk discounts, so your clinic or hospital can easily purchase 10 or more for a very small investment. However, OTC oximeters are not cleared by the FDA for medical purposes. Be prepared to spend more if you want FDA-approved oximeters.

Best Choices in Fetal Pulse Oximeters

To make shopping simpler, start by reading reviews on these top devices. These affordable yet powerful ox meters can serve for the long haul for general wellness, sports, or aviation.

Best Overall: FaceLake FL400 Pulse Oximeter Fingertip

This bright blue oximeter takes 24 seconds to obtain an accurate reading. Plus, the FL400 delivers a constant reading of blood oxygen levels. In product tests, FaceLake’s device consistently outperformed other pulse oximeters in reliability and accuracy.

The device includes a plethysmograph and perfusion index that lets you know if you took the pulse rate and SpO2 measurement properly. This eliminates “second guessing” and affords you peace of mind.

The latest version of this device offers an updated hardware design and upgraded firmware. Set the ox meter to detect when the user’s SpO2 and pulse rate exceed parameters. It beeps when either reading exceeds its pre-set maximum.

It comes ready to use. The kit includes a lanyard to make it easy to transport it and two AAA batteries. It comes with a 12-month warranty.

Best for At-Home Use: Zacurate 500BL Navy Blue Fingertip Pulse Oximeter Blood Oxygen Saturation Monitor 

The Zacurate oximeter delivers an accurate reading in 10 seconds and displays the information on a roomy digital LED display. It offers an easy to use function that makes it ideal for at home use. If you need to send an ox meter home with new parents to monitor their newborn’s oxygen saturation, this device offers a reading with a press of a button. It also comes with a 12-month warranty, a lanyard, and two AAA batteries, so you can use it out of the box, plus a silicone cover.

Best for All Ages: mibest OLED Finger Pulse Oximeter, O2 Meter, Dual Color White/Silver

The mibest company designed this pulse oximeter for use with all ages. Use it with infants, children, or adults. The design offers one-button operation, and its display offers three real-time readings—SpO2, pulse rate, and a pulse bar graph that provides pulse signal strength. This dual color oximeter displays data in four directions with your choice of four display modes. 

Adjust the monitor’s brightness level and know when the batteries need replacing since it signals you with a battery-low indicator. This ox meter also comes as a kit with batteries included and a detachable and adjustable lanyard.

Best for Fetal Pulse Oximetry: BabyO2 Baby Oxygen Monitor Foot 

The device comes with an available mobile app that you can set to deliver the alarm to your device. The app lets you set the alarm volume and threshold. The company provides both an Android and Apple iOS app. The device also comes with software for your personal computer. This lets the parents or doctor create reports on the fly to share with medical staff in either .pdf or .csv format.

Unlike designs for adults, this ox meter fits onto the baby’s foot like a sock. The breathable fabric used monitors accurately while providing a comfortable experience for the child. It comes in two sizes of sock wraps, so you can use it as the baby grows. Secured with Velcro, this device can easily get sent home with parents so they can monitor their baby’s oxygen saturation at home.

In Conclusion

Shopping for fetal pulse oximeters doesn’t have to become a complex undertaking. With savvy shopping, you can meet the needs of every age group—unborn, pediatric, and adult. Those designed for fetal monitoring use reflection pulse oximetry, while those for those older than toddler age typically use transmissive pulse oximetry. You can easily tell one used for fetal monitoring according to the leads used to attach to the fetus' head. 

Studying the needs of your medical facility proves key. You can gain a lot of insight from reviews from those in similar size practices. Even if you just started in medical procurement, obtaining these simple, effective devices can improve your facility’s function and cost it only a small investment.