I am at 27 weeks, almost 28 and I have a fetal heart listener which basically is a battery operated stethescope and at 27 weeks I still can't hear her heartbeat...I am thinking somewhere around 30 weeks you should be able to hear it.
https://answers.yahoo.com/question/index?qid=20080117154338AAGbbQU
Step 4. Listen carefully for a few minutes. If you do not hear your baby's heartbeat, try moving the stethoscope up or down on your baby's back. Be aware that you may pick up your own heartbeat as well.
http://www.livestrong.com/article/213330-how-to-hear-your-babys-heartbeat-with-a-stethoscope/
But typically... With modern Doppler devices, a fetal heartbeat can be heard from 10-12 weeks, although not hearing them up to 12 weeks is not particularly worrisome. With only a stethoscope you'd have to wait until about 18-20 weeks. A common mistake is to hear the radiated blasts of the maternal heart rate in this area.
https://answers.yahoo.com/question/index?qid=20080117154338AAGbbQU
How early you can hear a heartbeat will vary slightly based upon the development of the baby. In general, using an obstetrics ultrasound, you will be able to hear your baby's heartbeat when you are about 8 weeks pregnant. Or you may be able to hear the heartbeat during regular prenatal care visit at 10 weeks, or more commonly at 12 weeks, with a fetal Doppler. There are many factors that can influence just how early you can hear a heartbeat.
http://www.newhealthadvisor.com/When-Can-You-Hear-the-Baby's-Heartbeat.html
One of the most reassuring sounds a pregnant mother can hear is the steady thumping of her baby's heartbeat. Before 20 weeks of pregnancy, fetal heartbeats are typically monitored by doctors using a heart rate Doppler. While buying or renting an at-home Doppler is possible, it is often too expensive. Thankfully, after 20 weeks a baby's heartbeat can often be heard using a relatively cheap and easy-to-procure stethoscope.
http://www.livestrong.com/article/213330-how-to-hear-your-babys-heartbeat-with-a-stethoscope/
I'm not sure when I should be able to hear the heartbeat with my stethoscope. I've been kind of 1/2 heartedly listening knowing at 16 weeks I won't hear much.
https://answers.yahoo.com/question/index?qid=20080117154338AAGbbQU
1 To detect your baby's heartbeat, the Doppler has to hit the baby in a way that is completely right and proper. 2  Too much fat – If you have gained a lot of weight, or were heavy to begin with, this can interfere with hearing the baby.
http://www.newhealthadvisor.com/When-Can-You-Hear-the-Baby's-Heartbeat.html
1 Don't worry if you do not hear your baby's heartbeat right away. 2  How far along your pregnancy is, the baby's position, and the position of your placenta can all affect whether you detect your baby's heartbeat.
http://www.livestrong.com/article/213330-how-to-hear-your-babys-heartbeat-with-a-stethoscope/
You should be able to press firmly and hear a fetal heart beat at 19wks, with the bell side of your stethoscope. The heartbeat is best hear when the child's spine is close to the uterine wall.
https://answers.yahoo.com/question/index?qid=20080117154338AAGbbQU
Eartip: The eartips of a stethoscope fit into your ears. A good stethoscope will have eartips that offer comfort, seal and durability. Eartube: The eartube is the part to which the eartips are attached. Tunable Diaphragm: A traditional stethoscope consists of a bell and diaphraghm. The bell is used for light skin contact to hear low frequency sounds and the diaphragm is used with firm skin contact to hear high frequency sounds. Stem: The stemp connects the stethoscope tubing to the chestpiece. Tubing: All stethoscopes sold on myStethoscope.com do not contain latex. 3M Littmann stethoscope.
https://www.mystethoscope.com/stethoscope-faq.html
how soon can i hear heartbeat with stethoscope
You can hear heartbeat after 20 weeks with stethoscope.