pregnant woman jerky spastic fetal movements

Jerky Spastic Fetal Movements in Pregnancy – Why So Frantic?


Maybe you are worried about the movement you feel in your belly or are just a first-time mom who hasn’t had this experience before, or perhaps you didn’t experience it in your previous pregnancy (DS or DD)?

Not to worry. Having jerky spastic fetal movements during pregnancy is completely normal and absolutely safe.

It is part of the growing phase of your wonderful baby, and you’re beginning to experience what motherhood is about to become.

Keep on reading to learn comprehensively about why fetal movements can be so frantic and jerky in the womb, what to expect at each stage (weeks/trimester) in your pregnancy, and when it may call for concern or emergency if necessary.

First of all, a little introduction – What Do ‘Jerky’ and ‘Spastic’ or ‘Spasms’ Mean?

‘Spasticity’ should not be mistaken for ‘cerebral palsy,’ a condition where the body experiences stiffened muscles and remain contracted.

In this context, the reference is to “spasms,” a sudden involuntary muscular contraction.

On the other hand, ‘jerky,’ which also means to twitch, is a short (muscle) contraction that may occur repeatedly. It may cause discomfort but is typically not painful. (1)

In the context of frantic or jerky fetal movements in the womb, a baby’s movement in the womb is what you feel as twitching and spasms during your pregnancy.

Why do Babies Move in the Womb and What Causes it

Babies, like we grown adults move for several reasons, say:

  •  when sleeping,
  • when uncomfortable in a position, etc.

The surprising thing here is that it starts in human life, typically from when we were embryos (from conception up to 8 weeks). That means we moved even when we were in our mothers’ wombs.

According to the Handbook on Brain and Behavior in Human Development, movement begins in the fetus from 7-8 weeks.

When you deliver your baby, you will notice those kicks your LO makes when they sleep. You’ll remember what was happening when you were pregnant.

Moreso, other reasons why babies move include:

  1. When stretching
  2. During development – movements help them develop their muscles, joints, and bones.

What causes jerky fetal movements include:

  1. When you change sitting position.
  2. When they feel uncomfortable with activities going on out here (they hear too).
  3. When you lay down at night (usually).
  4. When you move your hand to your face.
  5. When you stretch
  6. Startle response – this is when you make a sudden movement, or there are activities outside (your immediate environment), and your baby responds by flinging out their arms and legs reflexively.

How long spastic fetal movements may last

It varies in women and at what stage of pregnancy you are.

Typically, it lasts from a few seconds to several minutes, up to an hour.

The length of time it lasts reduces as you progress in your pregnancy. This is because, as your baby grows, they take up space in the womb, limiting available space for regular movements as before.

Interestingly, every fetal movement is unique to pregnancies in the same women. You may not experience these frantic jerky fetal movements in all your pregnancies. One may be more evident than others, or another completely smooth, while another so jerky. Really normal.

When do Baby Movements begin in Pregnancy?

A fetus begins to move in the womb as early as 7-8 weeks. However, you only start to feel the movement from 18-20 weeks which is your second trimester.

The earliest you may feel your first baby’s movement can be at 16 weeks, and latest at 22 weeks.

Not feeling this movement at the earliest could possibly be:

  • if this is your first pregnancy (later pregnancies feel the first movement from 20 weeks)
  • the location of the placenta (between your belly and the womb)
  • if you are carrying twins, or
  • if one is obese

However, it is nothing to worry about as it will eventually come.

Smooth movement is totally normal, the same way as jerky fetal movements.

Types of Baby Movements in the Womb at Different Stages of Pregnancy – Weeks/Trimester

pregnant woman holding her belly -baby movements

First trimester – 0 weeks – 12 weeks

While fetus begins movement from as early as 7-8 weeks which is in the first trimester, you don’t feel their activities.

Second trimester – 12 weeks to 24 weeks


This is when you start to feel your baby’s movement in your womb.

This movement feels like;

  • flutters of a butterfly,
  • bubbles/popcorn popping
  • light rolls or tumbles
  • flickering
  • or tiny pulses – tiny “quickening” movement. Hence the name. (2)

You feel your baby’s quickening movement from as early as 16 weeks and sometimes as late as week 22.

For the first time, you may be confused about what exactly is the movement within you – is it gas or something?


Fetal hiccups happen later in the second semester, usually week 24, or sometimes from the third trimester.

Hiccups feel like jerky motions in your belly, and you may experience them several times a day or less. In contrast, other expectant mothers might not experience it at all.

Hiccups feel this way:

  • When you sit still and start feeling pulsing or rhythmic jerks coming from one side of your belly, that may be your baby’s hiccups.

As you progress into the third semester, from week 32, the frequency on a daily basis reduces.

Hiccups or Kicks?

Hiccups or kicks may be a little different from each other.

While hiccups are rhythmic movements you feel from the same side of your belly when you’re settled, kicks are random movements you feel in different parts of your stomach.

Kicks could be from top and bottom (head-down) or sideways.

Third trimester – 24 weeks to 40 weeks

As you enter your third trimester, you begin to feel stronger movements from your baby.

Kicks become common from week 22 to 26 and become stronger as your pregnancy progresses.


At 30-32 weeks, you begin to feel your baby moving several times a day and more active at certain times of the day, usually at night. Your baby turns less and kicks and jabs more at this time.

Further in the third trimester, at 40 weeks, your baby is now bigger and takes more space in the womb.

At this time, they tend not to move around as much as before because of the less available space.

Fetal Jerky Movements and Your Well-being – Should You be Concerned about a Seizure?

Due to misinformation, many pregnant women fear that these jerky spastic movements may be that their baby is having a seizure.

But that is wrong.

Nonetheless, when your baby’s movement becomes irregular from the norm you have been observing, you may need to call on your obstetrician.

However, babies can have seizures in the womb which is an abnormal, forceful, rapid, and/or repetitive jerky periodic movement which may indicate a seizure; and you should seek help.

When You Should Become Concerned and Seek Help

While movement in the uterus is generally expected and safe, there are when you need to be concerned.

First of all, you need to pay attention to your baby’s kicks and movements to understand the pattern and know your baby’s habits.

For hiccups, it is less common to get hiccups after 32 weeks. If your fetal hiccups continue daily after week 32 and last longer than 15 minutes, or it happens three or more times a day, you may need to talk to your obstetrician or midwife.

Also, when you notice your baby’s movement is much less typical than before or completely stops moving, you should seek medical help immediately.

A widely accepted range for babies’ movement:

  • Ten movements or kicks within two hours

However, some women may feel the same ten movements within 30 minutes.

Nonetheless, you should speak to your obstetrician or midwife if you feel very concerned.

Final Thought

While the jerky spastic fetal movements is normal in pregnancy, you should talk to your obstetrician and midwife and bring it up in your next appointment.


(1) Twitching and Spasms: Muscle twitch: Causes, symptoms, treatment, and prevention

(2) Quickening: Quickening in Pregnancy

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