Woah: Did You Know that Seaweed Can Dilate Your Cervix?!

We know what you’re thinking: “Seaweed? Near my cervix?!” Well, it’s actually not as crazy as you may think! Laminaria is a type of algae that, when shaped into sticks, has been used for hundreds of years to help dilate (aka open) the cervix (1). Let’s get into the details about this super seaweed and its relationship with your, er, happy clam below (P.S- this is not a DIY!)

Is this the kind of seaweed I eat?!

You may want to put down your fork; there are about 30 different species in the genus Laminaria, and some of them may make it to your dinner plate (2). For example, laminaria japonica—a species often used to make laminaria sticks (3)—is commonly known as kombu in Japanese cuisine (4). Sushi lovers, however, need not lose their lunch over the idea of eating vaginal vegetation: The only seaweed going near your spicy tuna (er, the real spicy tuna) is nori, which belongs to the genus Porphyra (5).

How do Laminaria sticks dilate the cervix?

Laminaria sticks are osmotic dilators, which is a super-fancy way of saying they work like expanding sponges. When inserted into a closed cervix, these sticks take in moisture from the surrounding tissue, gradually growing in diameter and slowly opening the cervix as they expand (7).The entire laminaria placement process typically only takes 5-10 minutes (and should only be done by a trained practitioner) but maximum dilation usually takes 12-24 hours after insertion (6).

Is natural seaweed really my only option here?

While natural laminaria can do some pretty amazing things, modern technology has created synthetic versions of this wonder plant that are far more efficient. In a 2015 study, Dilapan-S and Dilasoft, 2 synthetic versions of laminaria sticks, were found to expand faster and to greater sizes than natural laminaria sticks while also showing greater consistency, ultimately requiring fewer sticks for optimal results. Because they work so quickly, synthetic sticks are a more viable option for patients who need their cervixes dilated for a same-day procedure (8). That said, laminaria’s main benefit is actually how long it takes to swell, resulting in a very gentle and gradual expansion of the cervix with minimal discomfort. What all of this translates to is that some clinics still use laminaria while others, don’t.

Some members of the CYCLES+SEX community shared their experience with laminaria on Instagram, which can give us a better idea of it’s use (community narratives, baby!). One user wrote,

“Yes!!! We use this at the clinic I work at for surgical abortions after 12 weeks. You sit with them in for about 3 hours,”

and another added,

“My OB/GYN used seaweed sticks when I had an abortion. They preferred that method over the outdated machine method. Honestly, I did too. It hurt like HELL to insert them into the cervix, but was less traumatic than the other method.”  

Dr. Aviva Romm, physician and midwife, also shared her thoughts on laminaria use in a comment, writing, “this is an old practice known among women herbalists and midwives who know women’s healing work. Laminaria sticks are no longer sold [over the counter] because of risks with self care use. Definitely not a DIY birth practice - increases risk of intrauterine infection big time! Ditto with other gyno needs. Cool historical fact but there are better safer ways now...

And another commented,

“I work at an abortion clinic in Canada and we don’t use laminaria! 🤔. “

So basically, not every healthcare provider is stocking up on the seaweed!

And why would I need my cervix dilated in the first place?

There are a number of situations in which your cervix would need to be dilated with some help, such as:

  1. Childbirth: If an induction of labor is needed, one step may be to dilate the cervix, which causes the release of hormones known as prostaglandins (9). These hormones can both soften the cervix and help promote uterine contractions, both of which are vital to a vaginal birth (10).

  2. Abortion: While medications can be used to terminate a pregnancy up until 10 weeks after one’s last period, terminations that occur after this point will require what is known as an “in-clinic” or “surgical abortion (11). To help prepare one’s body for surgery, the cervix will need to be dilated.

  3. IUD retrieval: While removing an IUD is usually as easy as finding the strings and gently pulling, these devices sometimes like to instead pull a disappearing act. Once it is confirmed that the IUD is still in the proper position via ultrasound or, if an ultrasound is unavailable, pregnancy is ruled out AND it has been determined that the IUD strings have truly pulled a Houdini, laminaria can be used to dilate the cervix to allow the physician to locate and remove the IUD from inside one’s uterus (12).

While these are the three main situations in which laminaria use has been documented, these sticks can be used to slowly open the cervix in preparation for other gynecological procedures that require access to the uterus and/or fallopian tubes (6).

What are the risks of using laminaria sticks?

Though laminaria is natural and, as we mentioned, has been used for centuries to dilate cervixes, its use doesn’t come without risks, which is why it is no longer available for “personal use.”

While very rare, it is possible for the sticks to fragment  inside the body and become trapped within the vagina or uterus, leading to a number of subsequent issues and conditions.

Infection is another risk of laminaria use. If sticks fragment and pieces are left in the body, an infection can occur (13). Even if the laminaria sticks remain intact, the risk of infection increases if the sticks are left in for more than 24 hours (14).

Finally, some people may also have an allergic reaction to natural laminaria sticks. This reaction can be mild, usually presenting with general itchiness, or it can be severe enough to cause anaphylaxis, a life-threatening condition that can lead to hives and swelling of the throat that makes breathing difficult (15).

Again, these are very rare reactions. However, because there is always a slim chance of them occurring, it is VERY important to only use laminaria sticks under the direct orders and supervision of a trained physician or midwife.

If you find yourself needing to open up a bit more down there, work with your doctor or midwife to figure out which dilation method is right for you. And even though laminaria is not a well-used practice anymore, it’s still super cool that seaweed can play a role in reproductive health, no?

With contributions by: Briana Finneran, health care enthusiast in San José, Costa Rica