When Does a Baby Start Kicking?
Fetal movements begin as early as 7.5 weeks of gestation, but mothers typically perceive these movements around 19 weeks of gestation. 1, 2
Early Fetal Movement Development
- The embryo begins moving by 7.5 weeks of gestation, with a spinal reflex arc developing as early as 8 weeks of gestation 1, 3
- Peripheral cutaneous sensory receptors develop between 7 and 15 weeks of gestation, allowing the fetus to respond to touch 3
- By 9-10 weeks of gestation, several movement patterns emerge, including general movements, isolated limb movements, hiccups, and breathing movements 1, 4
- Early fetal movements can be classified into different patterns: "rippling" at 8 weeks, "small twitch" around 9 weeks, "twitch" at the beginning of 9 weeks, "strong twitch" at 9½ weeks, and "float," "swim," and "jump" at 10 weeks or later 4
Maternal Perception of Fetal Movements
- Despite early movement development, these movements are not strong enough to be perceived by the mother until the second trimester 3
- The average gestational age when mothers first perceive fetal movements is around 19 weeks (±1.5 weeks) 2
- The majority of women (73.3%) report initial perception of fetal movements between 18+0 and 20+6 weeks 2
- The timing can range from as early as 14 weeks to as late as 24 weeks in some cases 2
Factors Affecting Maternal Perception
- Several factors can delay maternal perception of fetal movements: 2
- Nulliparity (first pregnancy) - multiparous women report feeling movements almost one week earlier (18.6±1.4 weeks) compared to nulliparous women (19.4±1.4 weeks)
- Anterior placental position
- Higher body mass index (BMI)
- Advanced maternal age
Clinical Significance of Fetal Movements
- Fetal movements are an important indicator of fetal well-being and neurological development 1, 5
- Some movements have specific intrauterine functions, such as breathing movements for lung development 1
- In clinical settings, fetal movement is one component of the biophysical profile (BPP) used to assess fetal well-being 3
- Between 8 and 19 weeks, total absence of fetal movements never lasts longer than 13 minutes in normal development 5
Fetal Movement and Neurological Development
- Fetal movement patterns are spontaneously generated and closely associated with the development of peripheral and central nervous system structures 1
- The fetal startle reflex, a normal response to sound-vibratory stimuli, is present in healthy fetuses after 30 weeks of gestation 6
- Alterations in fetal general movements may suggest dysfunction of the developing nervous system 1
It's important to note that while fetal movements begin very early in development, what mothers describe as "kicks" are the movements that become strong enough to be felt through the abdominal wall, typically in the second trimester around 19 weeks of gestation.