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What is Laminaria? Uses and Risks

Laminaria Usage

Laminaria is a type of brown seaweed native to Japan that is believed to be an effective treatment for terminating pregnancy, speeding childbirth, preventing cancer, and aiding in various other medical conditions and procedures. While laminaria sounds like a wonder product, unfortunately, there is no strong evidence to support any of these uses.1

How Is Laminaria Used to End a Pregnancy?

Laminaria is sterilized, rolled, and dried to create a thin stick (or “tent”) that can be inserted in the cervix to force dilation. A laminaria cervical dilator is most commonly used in second-trimester abortions to expand the cervix to create easier access to the uterus to perform the abortion.

Once the laminaria tent is inserted into the cervix, it rehydrates by absorbing the fluid from the surrounding tissue and expands up to ten times its original size. As it expands, the laminaria tent slowly opens the cervix and promotes the release of endogenous prostaglandins, which cause contractions to prepare the women’s body to expel the fetus.

The Laminaria Cervical Insertion Process

During the laminaria insertion process, the patient is awake and positioned for a pelvic exam. A speculum is used to open the vagina, the cervix is cleaned, a numbing agent is applied, and then the laminaria tent is inserted. Spotting or cramping may occur.2 Patients are required to return for a follow-up appointment to have the laminaria tent removed within 24 hours. Laminaria tents that remain inserted for over 24 hours are at increased risk for infection and other complications.

In some cases, more than one laminaria tent is needed to achieve the desired dilation, and “additional sets over 1–2 days may be needed in challenging cases.”3

Laminaria Usage Risks

When used to open the cervix or to induce labor, laminaria can cause serious health side effects for the mother, including infection and rupture of the cervix.4 According to a study published in the Rocky Mountain Medical Journal, 1 out of every 14 women endured complications from laminaria use5, and a study conducted by the Swedish Association of Midwives found, “Complications in the use of laminaria include difficulty of tent removal, cramps, and menstruation-like symptoms in 8-9% of patients.”6

Risks during the laminaria insertion procedure include:

  • Incorrectly placed laminaria tent7
  • Acute pain causing the laminaria tent needing to be removed8
  • Allergic reaction to numbing medication
  • Rupture of membranes (amniotic sac)
  • Increased risk of infection
  • Cervical rupture
  • Convulsion
  • Uterus can move upward in the pelvis during insertion requiring stabilization with a tenaculum

Risks after the procedure include:

  • “Ballooning” or “dumbelling” of the laminaria, causing one end of the tent to swell making it difficult to remove9
  • Fragmentation and retention of the laminaria where parts of the laminaria tent break off and can cause infection, pelvic pain, bleeding, and even infertility when attempting removal10
  • Migration to the uterine cavity
  • Failure of the uterus to contract
  • Hemorrhaging
  • Fever
  • Endometriosis
  • Severe cramping
  • Depression
  • Pelvic abscess
  • Cystitis (inflammation of the bladder)

According to the insert for Dilateria, a brand name of laminaria, if a patient changes her mind after the laminaria tent is in place, she should be advised that the “long-term effects on the pregnancy and the fetus are unknown. Fetal and maternal well-being in this situation cannot be assured.”11

If you are considering a second-trimester abortion, but would like more information about all your options, schedule an appointment with one of our experienced nurses today. At MyNurse, we are committed to empowering women to choose with confidence.

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1 WebMD, LLC. (2023). Laminaria – Uses, Side Effects, and More. Retrieved July 2023 from WebMD.

2 UCLA Health (2023). Surgical Abortion (Second Trimester). Retrieved July 2023 from UCLA Health.

3 Fox, M.C., Hayes, J.L., SFP, (2007). Cervical preparation for second-trimester surgical abortion prior to 20 weeks of gestation. Contraception; 76(6): 486-495.

4 WebMD, LLC. (2023). Laminaria – Uses, Side Effects, and More. Retrieved July 2023 from WebMD.

5 Hern, W., (1975). Laminaria in abortion: Use in 1368 patients in the first trimester. Roc Mtn Med J; 72(9): 390-395.

6 Jonasson, A., (1984). Laminaria–a modern cervix dilatation method with more than a 100-year history. Jordemodern; 97(6): 187-195.

7 Herczeg, J., Sas, M., Szabó, J., & Vajda, G. (1986). Pre-evacuation dilatation of the pregnant uterine cervix by Laminaria japonica. Acta medica Hungarica, 43(2), 145–154.

8 Abramchenko, V. V., Gorgidzhanian, R. S., & Novikov, E. I. (1989). Laminari? v akuishersko-ginekologichesko? praktike [Laminaria in obstetrical and gynecological practice]. Akusherstvo i ginekologiia, (10), 12–14.

9 Fox, M.C., Hayes, J.L., SFP, (2007). Cervical preparation for second-trimester surgical abortion prior to 20 weeks of gestation. Contraception; 76(6): 486-495.

10 Allen, R.H., Goldberg, A.B., (2017). Cervical dilation before first-trimester surgical abortion (<14 weeks’ gestation). Contraception; 76(2): 139-56.

11 Cooper Surgical (2018). Dilateria (Laminaria Hyperborea): Instructions for Use. Retrieved June 2021 from 36999-B Model (1) (coopersurgical.com).

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