5 Reasons You Are Not Hearing Baby's Heartbeat

Mom listening to baby with stethescope
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Around the twelfth week of pregnancy you will normally have a prenatal appointment where your doctor or midwife tries to hear the baby's heart beat. This is typically done with a hand-held Doppler, which is a device that uses ultrasound waves to detect a heartbeat when it is too early to detect it with a stethoscope. It uses the same type of ultrasound technology that you would have in an ultrasound scan, but no picture is produced.

Sometimes, at this appointment, when they go to listen to the baby's heartbeat, you don't hear the baby's heartbeat as anticipated. This can be pretty frightening, but try not to panic. There are many reasons why you don't hear the heartbeat at this time, including:

1. Your Due Date is Wrong 

If you weren't sure of your last period or if your due date is calculated using something other than ultrasound, your due date may be later than you thought, meaning you really aren't twelve weeks pregnant. This makes your baby's heart beat would be harder to hear. This is one of the most common reasons, particularly if this is your first prenatal visit.

2. Uterine Position 

If you have a tilted uterus, you may have a harder time hearing your baby's heartbeat at first. This is because a Doppler is directional, so when your doctor or midwife aims it where they uterus would typically be, yours is placed slightly differently.

This is not a problem, just a difference. This may also mean that it takes awhile to find the heartbeat, this is also not problematic, just a small baby in a big body.

3. Baby's Position

At this stage of pregnancy, your baby is very small. The Doppler needs to hit the baby in just the right way to catch the heartbeat.

Sometimes it simply takes a lot of patience and a bit of luck to find the baby and "catch" it via the Doppler. The waiting to hear the heartbeat while your practitioner is searching might seem like it takes forever. The time it takes to find the heartbeat is not indicative of a problem.

4. Maternal Size 

If you are overweight, sometimes the padding between baby and the Doppler is significant enough to cause it to be harder to hear the baby. Typically this can be overcome by using a transvaginal ultrasound if you or your practitioner are worried about the baby. This is not always a problem through your entire pregnancy, but mainly when the baby is so small and the uterus is tucked into the pelvis. As you get into the second and third trimester, it usually becomes easier to find.

5. Miscarriage

Sometimes the reason you are not hearing the heartbeat is because you are in the process of miscarrying, even if you have not had any signs of miscarriage, or you had had a miscarriage. This may be a missed miscarriage, where you haven't yet had any signs of miscarriage, or even a blighted ovum, where the baby never really begins to form, despite you having pregnancy symptoms. This is the reason that worries most people when a heartbeat isn't heard.

You should talk to your practitioner if this is your concern. They can help you understand what is going on and what the best, next steps are for your care.

What Happens If You Don't Hear the Heartbeat

If you have an appointment and do not hear the heartbeat you may be told to come in a week or two to try again or even wait until your next appointment, depending on how far along you are in your pregnancy. You may also be scheduled for an ultrasound to check on the baby within the next week, depending on why your doctor or midwife feels like they are not hearing the baby.

If this happens, try not to panic.

It is a fairly frequent occurrence and it has some perfectly plausible explanations. Worrying about it won't do anything but make you feel terrible and won't change the outcome. You should convey your level of concern to your practitioner to get guidance from them for a quick resolution.

Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Fifth Edition.

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