When does fetal heartbeat begin?
Fetal heart development typically begins in the third week of gestation. The heart starts beating in the fifth week, which is defined as only week three in terms of fetal age. Note that when it comes to calculating pregnancy length, there’s a significant difference between gestational age and fetal age.
- Gestational age: It represents the number of completed weeks since the first day of your last menstrual period (LMP). It’s a popular method used by doctors that technically includes 2 weeks of time before the mother actually became pregnant.
- Fetal age: Alternatively, fetal age is determined by the tentative day of conception, and is approximately 2 weeks shorter than the gestational age.
For the purposes of this discussion, we will refer only to the gestational age of pregnancy.