Internal fetal monitoring involves the placement of an electrode directly onto the scalp of the baby while it is still in the womb. This test is performed to evaluate the baby's heart rate as well as the variability of heartbeats at the time of labor.
While IFM is most often used during high-risk births, it can also be used in a low-risk birth if the care team is unable to get an accurate reading from external monitoring techniques, such as auscultation and EFM.
How Internal Fetal Monitoring Is Performed
The IFM is inserted through the cervix to the part of the baby's body closest to the opening (typically the scalp). If the mother has not broken her water, an amniotomy.A fetal electrode will then be placed by screwing a tiny wire into the top layers of the baby's scalp.
Advantages of Internal Fetal Monitoring
Internal fetal monitoring allows for direct monitoring of the baby's heart as opposed to an auscultation which is an indirect form of monitoring. Auscultation employs the use of a device that listens through the woman's stomach, either in the form of a stethoscope or an ultrasound fetoscope. Auscultation is the most common technique used for low-risk pregnancies.
Despite its advantages, there are a number of risks associated with IFM, including:
- Bruising or scratching of the baby's scalp
- The risk infection to the mother or baby from an outside source
- The restriction of movement for the mother which can make labor more painful and difficult
- The risk of infection from mother to child (IFM is contraindicated in women with HIV, herpes, and hepatitis)
The IFM procedure itself has attracted controversy among some practitioners who believe it is unnecessarily invasive. Some studies have suggested that its use is associated with higher, rather than lower, rates of cesarean births and forceps delivery.
One study conducted in 2013 reported that, of 3,944 women in whom IFM was used, 18.6 percent ended up getting a cesarean versus 9.7 percent who didn't have an IFM. The rates of fever in women was also nearly three times higher (11.7 percent versus 4.5 percent).
No differences in the health were seen in babies exposed to IFM compared to those who were not.
- Harper, L.; Shanks, A.; Tuuli, M.; et al. "The Risks and Benefits of Internal Monitors in Laboring Patients." Am J Obstet Gynecol. 2013; 209(1): 38.e1-38.e6.