A fetal heartbeat can typically be detected via ultrasound around 5 to 6 weeks of pregnancy. This translates to roughly 35-42 days from the first day of the woman's last menstrual period (LMP).
It's important to note that this is when cardiac activity is first detected. While the term "heartbeat" is commonly used, the heart is still developing at this stage, and what's being observed is the pulsing of cardiac tissue.
Here's a breakdown:
- Weeks 5-6 of pregnancy (from LMP): Cardiac activity, often referred to as a heartbeat, can be detected by ultrasound.
- Before Week 8: The developing baby is referred to as an embryo.
- What you're seeing: Pulsing cardiac tissue; the heart isn't fully formed yet.
Factors that can affect when a heartbeat is detected include:
- Accuracy of dating: It's crucial to have accurate dating of the pregnancy based on the last menstrual period or early ultrasound. If ovulation occurred later than expected, the heartbeat may be detected later.
- Ultrasound type: Transvaginal ultrasounds, which are inserted into the vagina, often detect a heartbeat earlier than abdominal ultrasounds.
- Equipment quality: Higher-quality ultrasound equipment may detect a heartbeat earlier.
- Maternal factors: Maternal body mass index (BMI) can sometimes affect ultrasound image quality.
If a heartbeat isn't detected at the initial ultrasound, your doctor will likely schedule a follow-up scan in a week or two to reassess.
