Does Fetal Heart Rate Dictate the Gender of a Child?

During my recent “Woman’s Health Rotation”, i had the pleasure of conducting a large number of pre-natal exams with expecting mothers.  I was repeatedly asked if it was possible to determine the gender of their soon to be son/daughter by assessing the heart rate of the unborn child (more commonly referred to as the fetal heart rate).  The measurement/assessment of the fetal heart rate is a standard portion of every pre-natal exam, and the expected norm is between 120 to 160 beats per minute (outside of this range is considered abnormal).  I found the above query rather perplexing, and not knowing the answer to the question, i decided to investigate!

A review of this claim reveals the following:

-the most common claim regarding the above query is that a male fetus will have a heart rate of under 140 beats per minute and a female fetus will have a heart rate over 140 beats per minute (strangely no claim is made for  a fetal heart rate of exactly 140 beats per minute)

-the main physiological basis given for the above claim is that females typically have a higher “metabolic rate” than males, and consequently a female fetus will have a higher heart rate than a male fetus 

A review of current literature reveals the following:

-there is no basis for the claim that the gender of a fetus will dictate heart rate.  Additionally there is no plausible mechanism to explain why a specific fetal heart rate would indicate a specific gender of a fetus.  Additionally, females do not typically have higher “metabolic rate” than men, and men do not typically have a higher “metabolic rate” than women.  Metabolic rate is not dictated solely by gender, but instead is dictated by a multitude of different factors  

-much like children or adults, fetal heart rate is not dictated by gender but instead by underlying pathology, overall health, and activity level

-a fetus’s heart rate will vary throughout the day depending on activity level (for example when the fetus is sleeping a lower heart rate is expected that when the fetus is awake and moving)

-a review of PubMed reveals that several small separate studies were conducted in the 1990’s to determine if fetal heart rate could be used to determine the gender of an unborn child, and no correlation/relationship was found.  A 2006 study conducted by McKenna, Ventolini,  Neiger, and Downing determined that “Contrary to beliefs commonly held by many pregnant women and their families, there are no significant differences between male and female FHR during the first trimester”. 

So what does this all mean?

There is no basis to the claim that fetal heart rate can “predict” the gender of an unborn child.  The claim that fetal heart rate can predict the gender of an unborn child seems to be “an old wife’s tale” that has been passed on from generation to generation with no actual evidence to support it. 

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2 Responses to “Does Fetal Heart Rate Dictate the Gender of a Child?”

  1. Matthew Says:

    My sons fetal heart rate was 155 bpm, does that make him a girl?

    • theskepticalsamurai Says:

      Matt…

      read the article my friend…and all your quesitons will be answered! haha

      Either that…or i have some potentially “bad news” to tell you about your “son”!

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