The first meaning is 'metre' which is a measurement of length. If the 'm' stands alone it is metre. The second meaning is 'milliâ¦' which means a thousandth. In this case 'm' can not stand alone, we need to know what we have a thousandth of; if it is weight, length or some other thing. Example: mg means 'milligram', a thousandth of a gram. Example: mm means 'millimetre', a thousanth of a meter.
At about six weeks into pregnancy (four weeks from conception), you should be able to see your baby's heartbeat on ultrasound. The typical heart rate at this age is about 100 beats per minute.
The baby's heart starts to beat at around 6 weeks. You may be able to hear â and see â your baby's heart beat for the first time when you're about 8 weeks pregnant if you have an early ultrasound exam. Otherwise, you'll probably first hear it with a fetal Doppler at a regular prenatal care visit. Your caregiver may be able to find it with the Doppler as early as 10 weeks, but it's more common to hear it at 12 weeks. How early the sound can be picked up depends on your baby's position in your uterus, your weight, and the accuracy of your due date.