Miscarriage is referred to as a natural loss of pregnancy before 20 weeks. About 80% of miscarriages occur before 12 weeks. Of these 50 - 70% occur even before a woman realizes that she is pregnant. Such miscarriages mostly occur due to chromosomal abnormalities. In general, first trimester is usually characterized with high risk of miscarriages. However, it is believed that miscarriage risk after you see heartbeat is greatly reduced. Nonetheless, the miscarriage statistics regarding this issue presents an altogether different picture.
Miscarriage Statistics after Seeing Heartbeat
Fetal heartbeat can be detected in an ultrasound as early as 5 weeks of gestational age. Although, the heart of your baby is not fully developed at this stage, myocardial muscles have begun their contraction. A heart rate beyond 120 is considered normal. Once the heart rate is heard on an ultrasound, the risk of miscarriage drops to about 5%.
However, this is true only if you have no other complication and that you do not experience any vaginal bleeding. Women who experience vaginal bleeding are likely to have about 16% chances of miscarriage, even after hearing a heartbeat. Also, the miscarriage chances are low only if you hear a strong heartbeat on an ultrasound. Abnormal fetal heartbeat may elevate your risk of having a miscarriage.
Other Factors Influencing Miscarriage Statistics
Miscarriage statistics is greatly influenced by several factors. Age of mother is one such prime factor contributing to miscarriages. Women over 35 years of age have 16% chances of miscarriages after hearing a heartbeat. Whereas women over 40 years of age have 20% chances of miscarriage at this stage. Besides, women with preexisting medical conditions, history of substance abuse are also more likely to have miscarriages than healthy women at this stage.
Incidentally, the history of recurrent miscarriages also elevates your chances of miscarrying the next pregnancy by about 17%. Thus, the figures indicating lower chances of miscarriage after hearing a heartbeat are for healthy women under 30 years of age, without any problems. Even then, a miscarriage rate of 5% is still quite high, given the total number of pregnancies.
Some pregnant women may find the above information a little unnerving. However, one must understand that, every pregnancy is different and unless you are showing some clear signs of problem, there is probably no need for you to worry. Many a time, a heartbeat is not detected at 5 weeks.
This is because, gestational age is calculated from last day of your periods and not from the day when conception occurred. In this calculation, it is assumed that you ovulated on 14th day of your cycle. However, if you have ovulated late, then your baby won't be old enough to produce a heartbeat at 5 weeks. In this case, you may have to repeat an ultrasound after a week or two.
Apart from an ultrasound, your doctor may also recommend some blood test, that mainly includes testing for your hCG levels. If your hCG levels do not raise as per expectations, then you are considered as a risk for miscarriage. Also, if you have constant or reduced hCG levels, it may indicate that your fetus has stopped growing, thereby invoking a need for D&C.
On the other hand fetuses that show weak or no heartbeat on ultrasound at 5 weeks, may still continue to grow and produce heartbeat in a few weeks time. It is not unusual to hear the first fetal heartbeat at 10 weeks of gestational age.
Do not let the above mentioned miscarriage statistics alarm you, in case you are waiting for your first ultrasound. Always remember, most pregnancies are carried to a full term without major complications.