The Fetal Heart Rate Fluctuation


“If the heart rate accelerated, the researchers surmised the fetuses hadn’t totally grasped the new sounds. If the heart rate decelerated, it meant the fetuses found the nursery rhyme familiar.”(News, July 2015)

Human Life begins with the development of an Embryo at Stage one when a sperm fertilizes an ovum and together, they will form a single cell called Zygote. The zygote is separated quickly resulting in the creating of a multi-cellular organism. Physiological development starts from the very conception of Zygote itself. Prenatal development which includes the development of the embryo starts with fertilization. The stage of human development that begins from the eight complete weeks after fertilization is known as Fetus, the germinal stage of embryonic development, and continues in fetal development until birth.

Fetal’s heart-rate-monitoring measures the heart rate and the rhythm of the fetus. The count of heartbeats of the fetal remains 110 to 160 on an average. It can be varied by 5 to 25 beats per minute. The fetal’s heart-rate may change as the baby responds to the conditions in the mother’s uterus (Weiss, July2020). For the abnormal fetal heart-rate may mean that the baby is not getting enough oxygen or there are some other problems that the baby is facing.

At about 6 weeks, the baby’s heartbeat can usually be detected. At the age of 30 weeks, a fetus can remember sound for 10 minutes. The fetus can respond to the sound and prefers to hear some sounds by their 34th weeks in the ‘utero’. By the 38th week of the pregnancy, the baby’s memory is evident (News, July2015).

A scientist (Alan P. Krueger) and his co-investigator (Garvan) conduct research about early developmental exposure to sound, specifically maternal voice. They asked 32 women to repeat aloud the same 15-second nursery rhyme twice a day for six weeks from their 28th week of pregnancy through their 34th weeks. This result involved measuring the fetus’s heart rates while the unborn babies listened to a recorded female voice repeat the same nursery rhyme that was spoken at home by the mothers.

“If the heart rate accelerated, the researchers surmised the fetuses hadn’t totally grasped the new sounds. If the heart rate decelerated, it means the fetuses found the nursery rhyme familiar.”(News, July2015)

The scientist and its co-investigator found that by the 34th week the heart rate of the fetuses began to decline while listening to the recording. During thirty-eight weeks i.e. four weeks later repeating of the rhyme was stopped by their mothers.

A mother’s voice is the sensory stimulus for an unborn baby. The fetuses are simply responding to their mother’s voice rather than to a familiar pattern of speech. The heart rates of the fetuses were slightly accelerated when this group listened to a recording of a new nursery rhyme.

The fetuses in the experimental group were responding to a nursery rhyme, that they begin to show evidence of the gestational age by 34 weeks. In this way, they have built a capacity of memorizing the things that they hear inside the womb.

The study’s goal was to increase basic knowledge of not only when but ultimately how humans learn and remember. The new technologies that feature the neonatal intensive care units play a vital role in a baby’s experience as it provides preterm infants with a greater scope of survival. It also alters the stimulation patterns for the development of fetuses inside and outside of the womb.

Further study is needed to more fully understand in the context of outgoing development in the last trimester of pregnancy that affects learning and memory.


Work Cited:

  • Robin Elise Weiss. (2020, July 27). How to Determine If Your Baby’s Fetal Heart Rate Is Normal”, 2020,


  • News, N. (2015, July 08). Evidence of Learning and Memory in Fetuses Six Weeks Prior to Birth. Retrieved June 25, 2020,
2 Comments on "The Fetal Heart Rate Fluctuation"
  • Amari Reply
    December 23, 2020 at 9:18 am

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    December 25, 2020 at 5:17 pm

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