Although many parents find out the gender of their baby via ultrasound about halfway through their pregnancy, the 18 to 20 week wait can seem excruciatingly long for some expecting parents. Folk tales from the days before scientific gender prediction sometimes fill in the gaps in knowledge. Some myths assert you can tell the gender of a baby by looking at the size and shape or your baby bump while others insist the date of conception determines whether you carry a boy or girl. A more modern method relies on the baby's heartbeat as an indicator of gender.
Significance
Pregnancy myths state that boys have a slower heart rate in utero and girls a faster one. A normal heart rate in utero is between 120 and 160 beats-per-minute. In theory, a heart rate of over 140 means a girl while one under 140 indicates a boy. Dr. Elana Pearl Ben-Joseph, a medical editor at the Kids Health from Nemours website, cautions that although this is a fun and harmless myth for predicating gender, no medical evidence proves it works.
Identification
Medical practitioners use a fetal Doppler---an instrument that bounces sound waves off of the fetal heart--to try to listen to baby's heartbeat starting at around nine to 10 weeks after your last menstrual period. Although the heart beat can be seen on ultrasound as early as four weeks after conception, Dr. Marjorie Greenfield, an obstetrician and medical expert at the Dr. Spock website, cautions that hearing the heartbeat prior to 12 weeks relies upon luck and the positioning of the baby. Medical practitioners obtain the measurements for the heart rate by counting the beats for a full minute---or counting them for 15 seconds and multiplying that number by four.
Evidence
Even though using the heart rate to predict baby gender can seem more scientific than evaluating the size and shape of your baby bump, medical studies evaluating this phenomenon indicate it remains just as much a myth as less scientific methods. A 2006 medical study led by Dr. Gary Ventolini, director of the Department of Obstetrics and Gynecology at Wright State University, evaluated almost 500 births and found that the heart rate had no correlation to a baby's gender.
Dr. Terry J. DuBose, director of the diagnostic medical sonography program at the University of Arkansas for Medical Sciences, conducted a similar study of around 400 pregnant women in Austin, Texas, from 1983 to 1987. He found that heart rate did not vary with gender, but it did change according to the age of the baby.
Warning
Although this particular gender prediction myth does not harm you or the baby, some old folk tales might require to ingest or handle dangerous or toxic materials, such as drain cleaner or herbs. Steer clear of any gender-prediction myths that encourage you to do anything hazardous to your health and well-being, or that of your baby.
Potential
Your baby's heart rate will often vary from appointment to appointment, regardless of the gender. Ben-Joseph suggests that the baby's size and activity level usually affect the heart rate, so a sleeping baby will usually have a lower heart rate than an active one. The heart rate will usually slow down as your baby moves toward full-term.
