30 March

3. Interesting fact about Third month of pregnancy

Did you know that the fetal heart beats twice as fast as the mother? 

A normal fetal heart rate usually ranges from 120 to 160 beats per minute when the baby is in the mother's uterus. It is measurable by ultrasound from around 6 weeks onwards and the normal range varies. It increases to around 170 beats per minute at 10 weeks and decreases from then to around 130 beats per minute at full term.


Fetal heart beating is first visible on sonography around 6 weeks of gestation. The FHR is then usually around 100 to 120 beats per minute (bpm).

A slow fetal heart rate is called as fetal bradycardia and is usually defined as 1:

  • FHR <100 bpm before 6.3 weeks gestation, or 
  • FHR <120 bpm between 6.3 and 7.0 weeks 

A rapid fetal heart rate is called as fetal tachycardia and is usually defined as: 

  • FHR >160-180 bpm 

Fetal bradycardia can occur due to 

- conduction abnormalities in the fetus

- fetal head compression

- umbilical cord occlusion

- maternal exertion

and many other causes.

When the fetal heart rate is less than 90 beats per minute in the first trimester than it is considered not a good sign and the chances of the fetus survival is less.

Fetal tachycardia is defined as a heart rate above 160-180 beats per minute and typically ranges between 170-220 bpm 

It can occur due to 

- maternal hyperthyroidism

- maternal medications

- maternal infections 

- In utero infections 

- Fetal anemia

- Chromosomal abnormalities in the fetus like Trisomy 13 or Turner syndrome

Last modified on Thursday, 02 August 2018 17:12
Dr Padma

Dr Padma is a Family care physician and is the Founder and CEO of MedHealthTV.


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