My Baby’s Head is Low, But My Cervix is Not Yet Dilated (Lightening 101)

When your baby’s head is in a low position, this is called lightening. Your baby’s head moves past the abdominal area and towards the pelvic area. This happens near the time of delivery. Other signs of lightening include decreased heartburn and difficulty breathing, but frequent peeing and discomfort when walking. Lightening is only one of the criteria healthcare providers check to determine whether labor has started; it doesn’t always mean that labor will begin soon. Cervical dilation, bloody show, and uterine contractions are some other signs to watch out for. However, if the baby’s head is low and the cervix is not dilated for a long time, this could signal slow labor. Your healthcare provider may decide to intervene to ensure a smooth delivery.

What does it mean when my baby’s head is “low”?

When you’re told that your baby’s head is “low,” your midwife or obstetrician might be referring to “lightening.”

As you get closer to labor, your baby’s head slowly edges past your abdominal area and engages into position between your pubic bones in preparation for delivery.

Some signs of lightening

Moms might notice some changes in their bodies that are related to lightening.

A pregnant woman and her husband are walking into the hospital because the woman believes she's going into labor.

When a baby’s head is engaged with the pelvic bones, the pressure on the diaphragm moves towards the pelvis.

You may find it easier to breathe and have fewer heartburn symptoms, but it might become harder to walk properly and hold in your pee. 

The pressure that your baby’s head places on your pelvis may translate to occasional bouts of pain, but it typically comes and goes and isn’t consistent.

If the pain worsens or doesn’t stop, it’s best to see your obstetrician.

A physical exam done by a healthcare provider or an ultrasound can also help determine your baby’s position in your womb and check whether their head is already engaged.

When does lightening happen?

During the first and second trimester of pregnancy, and even most of the third trimester, your baby can change their position endlessly.

One day they could be lying down horizontally, then upside down the next. This is perfectly normal.

Lightening usually happens in close proximity to labor. For some moms, lightening can happen as early as a week or two before labor officially starts (36 weeks in), while for several mothers, lightening might even happen after labor starts.

When your child’s head is still mostly above your hip area, it’s considered “floating.”

As it starts to descend downwards, your midwife or obstetrician may begin to measure or estimate how far your baby’s head is in relation to the pelvic bones.

This helps them decide if labor is happening as planned or if your baby’s head is descending too fast or too slow.

Does lightening mean I’m all set for labor?

Not necessarily. If you haven’t officially started labor yet, your baby’s head may still disengage from your mid-pelvis.

This is because labor is determined by several factors, not just lightening. This includes uterine contractions, bloody show, and dilation and thickness of your cervix.

In this case, if your baby’s head is low but your cervix has not yet dilated, you might not be in labor yet. However, if it’s been quite some time with your baby’s head very low but your cervix isn’t dilated, there’s a possibility that you may be in labor, but it’s progressing slowly.

Again, this will depend on your healthcare provider’s assessment. The healthcare team may decide to give you medications to speed up labor and reduce your baby’s chances of distress.

If your baby is already in distress, they may pass stool which could be dangerous when swallowed inside the womb. In this case, an emergency cesarean may be needed.

What does “dilated” mean?

When you’re due to give birth, one of the many factors your obstetrician will consider is how dilated your cervix is.

A gynecologist is showing a model of a vagina to her patient, to show how things will change when the pregnant patient is dilated and ready for labor.

The cervix is a slightly tubular-shaped tissue connected to the lower part of the uterus and is part of the birth canal.

Your baby will need to pass through this area, so the cervix needs to dilate to accommodate the head and body of your child.

Healthcare providers can measure how dilated your cervix is through a pelvic exam. For term babies, the cervix usually has to dilate up to 10cm to make it easy for them to pass through.

FAQs

Should I worry about my baby’s head circumference or head shape after giving birth?

Not necessarily. Your baby’s skull bones are soft and slightly malleable when born.

This is primarily because passing through the birth canal can cause pressure on your baby’s head.

Instead of being rigid, the bones are soft to prevent any fractures or brain injuries. Typically, the head circumference and shape corrects itself on its own within the first few days of life.

Should I worry if my baby’s head is low at 20 weeks?

Most of the time, babies at this stage move around the womb a lot.

Your healthcare provider will check for other signs of labor, such as cervical dilation, bloody show, and uterine contractions.

To be safe, have a check-up to rule out other concerns.

Takeaway

Lightening may or may not signal labor. It is one of several criteria used to determine whether women are in active labor.

The best way to ensure you and your child are safe is to be monitored closely by a healthcare team during this time. 

Sarah is a healthcare writer, motivated by her love of reading books while growing up. She took up human biology and further studies in medicine, in order to fulfill her passion for helping kids. While she isn't a biological mother yet, she has taken two young dogs, named Indy and Obi-Wan, under her wing. She would love to someday travel the world and meet kids from different cultural backgrounds.

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