Some even shared that their boys actually had higher heart rates, while others shared that their girls had lower beats per minute.

For example, on, most women reported that this myth did not work. Though many women swear heart rate clued them in, the overall results are mixed at best. Still, you can find lots of forum topics across the web on this subject. They continue to increase until they peak around week 9, between 140 and 170 bpm for boys and girls alike. The beats per minute (bpm) start at a slow 90 to 110 bpm and increase daily. You can even see and measure this flicker of light on an ultrasound. The truth is, your baby’s heart will likely start beating sometime around week 6 of your pregnancy. If it’s over 140 bpm, you’re having a baby girl. You may have heard that your baby’s heart rate can predict its sex as early as the first trimester. There are lots of old wives’ tales surrounding pregnancy. In fact, there seems to be little difference in the average beats per minute between males and females. In such pregnancies, at least one follow-up scan in late first trimester is warranted.The idea that a baby’s heart rate can predict this sex is a myth. When a slow embryonic heart rate is detected at 6.0-7.0 weeks, the likelihood of subsequent first-trimester demise remains elevated (approximately 25%) even if the heart rate is normal at follow-up. Pregnancies with a borderline heart rate early in pregnancy followed by a normal heart rate had a demise rate of 7.6% (nine of 118), which is similar to those with normal heart rates early in pregnancy followed by normal heart rates at follow-up (P =. This rate of demise was significantly higher than that of 7.2% (28 of 390) in pregnancies with a normal heart rate at 6.0-7.0 weeks and a normal heart rate by 8.0 weeks (P <.001, Fisher exact test). There were 59 pregnancies with a slow heart rate at 6.0-7.0 weeks and a normal heart rate at follow-up US by 8.0 weeks 15 (25.4%) resulted in first-trimester demise. The rates of first-trimester demise were 60.6% for pregnancies with slow heart rates at 6.0-7.0 weeks (188 of 310), 17.4% for those with borderline heart rates (103 of 593), and 9.1% for those with normal heart rates (186 of 2034). The Fisher exact test was used for all statistical comparisons.

Pregnancies were excluded from the analysis if they were lost to follow-up before the end of first trimester. The heart rate was classified as slow if it was fewer than 90 beats per minute prior to 6.3 weeks or fewer than 110 beats/min at 6.3-7.0 weeks, normal if it was 100 or more beats/min at less than 6.3 weeks or 120 or more beats/min at 6.3-7.0 weeks, or borderline if it was 90-99 beats/min prior to 6.3 weeks or 110-119 beats/min at 6.3-7.0 weeks. Singleton pregnancies with an embryonic heart rate measured on a 6.0-7.0-week US scan were identified. The study was Health Insurance Portability and Accountability Act compliant. Institutional review board approval was granted informed consent was not required. To determine retrospectively the outcome of pregnancies in which the embryo has a slow heart rate at 6.0-7.0 weeks gestation and a normal heart rate at follow-up ultrasonography (US) by 8.0 weeks gestation.

Normal heartbeat for 12 week fetus