Hearing a baby’s heartbeat for the first time is an exciting milestone for new parents-to-be.
A fetal heartbeat may first be detected by a vaginal ultrasound as early as 5 1/2 to 6 weeks after gestation. That’s when a fetal pole, the first visible sign of a developing embryo, can sometimes be seen.
But between 6 1/2 to 7 weeks after gestation, a heartbeat can be better assessed. That’s when your doctor may schedule your first abdominal or vaginal ultrasound to check for signs of a healthy, developing pregnancy.
After a positive pregnancy test, your doctor may recommend you schedule an early pregnancy ultrasound scan around 7 1/2 to 8 weeks of pregnancy. Some medical practices don’t schedule the first ultrasound until between 11 and 14 weeks.
Your doctor may recommend this scan as early as 6 weeks if you:
- have a prior medical condition
- have had a miscarriage
- had difficulty maintaining a pregnancy in the past
During your first ultrasound appointment, the doctor or ultrasound technician will check for the following:
- confirm viable pregnancy, and check for non-viable molar or ectopic pregnancy
- confirm baby’s heartbeat
- measure baby’s crown-to-rump length, which can help determine gestational age
- assess abnormal gestation
Your baby’s heartbeat should be between 90-110 beats per minute (bpm) at 6 to 7 weeks. By the ninth week, your baby’s heartbeat should reach 140-170 bpm.
Why you might not hear baby’s heartbeat
You might not be able to hear a baby’s heartbeat at your first ultrasound. Most commonly, this is because it’s too early in the pregnancy. This doesn’t necessarily mean there’s a problem.
Your doctor may recommend you schedule another ultrasound 1 to 2 weeks later.
Other reasons you might not hear the heartbeat include:
- having a tipped uterus
- having a large abdomen
- being less far along than you thought
If no heartbeat is detected, your doctor will check your fetal measurements. Your health care provider may be concerned if there’s no fetal heartbeat in an embryo with a crown-rump length greater than 5 millimeters.
After week 6, your doctor will also be concerned if there is no gestational sac. Your doctor may request a blood test to confirm the pregnancy, or request you come back a few days later for another ultrasound.
A 1999 longitudinal study of 325 women in the United Kingdom who had a history of miscarriage reported that if a heartbeat is detected at 6 weeks, there’s a 78 percent chance of the pregnancy continuing. At 8 weeks, there’s a 98 percent chance, and it goes up to 99.4 percent after 10 weeks.
At your first scan, your doctor or an ultrasound technician will use a transvaginal ultrasound, or a 2D or 3D abdominal ultrasound.
The transvaginal ultrasound is used during early pregnancy to get a clear image of an embryo. A 3D ultrasound allows the doctor to better see the width, height, and depth of the fetus and your organs.
Detecting a fetal heartbeat is very difficult, if not impossible, for the human ear.
But some expecting mothers claim they can hear their baby’s heartbeat through their belly. This may be possible in a quiet room likely late during the second or third trimester.
Don’t be concerned if you can’t hear your baby’s heartbeat at home.
If you are worried about your baby’s heartbeat, your safest option is to reach out to your doctor. They can schedule a sonogram to reassure you that your baby’s heartbeat is normal.
There are now hundreds of apps and devices marketed to expectant parents where you can listen to your baby’s heartbeat at home. But your doctor may warn you against using an at-home device.
The quality of these apps and devices varies greatly. They may give you an inaccurate heartbeat reading and cause unnecessary concern or panic.
Talk to your doctor and ask if they recommend an at-home device. They can tell you if it’s safe to use during your pregnancy.
Throughout pregnancy, your baby’s heart will continue to develop. A fetal heartbeat starts at between 90 and 110 bpm during the first weeks of pregnancy. It will increase and peak at around weeks 9 to 10, between 140 and 170 bpm.
After that, a normal fetal heartbeat is considered between 110 and 160 bpm in the second and third trimester. Keep in mind, your baby’s heartbeat can vary throughout pregnancy and at each prenatal appointment.
Your doctor may be concerned if your baby’s heartbeat is too slow, too fast, or is irregular. If so, there’s a rare chance your baby could have a heart condition. That’s why your doctor will monitor your baby’s heartbeat at every appointment.
If your doctor has any concerns about the development of your baby’s heart, they may schedule a fetal echocardiogram to further examine your baby’s heart.
Your doctor will monitor your baby’s heartbeat at each prenatal appointment. You may be able to hear your baby’s heartbeat for the first time as early as 6 weeks.
If you are concerned about your baby’s heartbeat, talk to your doctor. Your prenatal team can keep a close watch on the heartbeat throughout your pregnancy and into labor and delivery.