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THERAPIES & TRADITIONS · GUIDE

Spleen 6 (Sanyinjiao, SP6): Traditional Description, Research and Pregnancy Caution

Spleen 6 (Sanyinjiao, SP6) is a lower-leg acupuncture point. See its traditional description, research on period pain and labor, and why pregnancy calls for caution.

Content last updated . This page has not been medically reviewed.

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What this page covers

Spleen 6, written SP6 and known by its Chinese name Sanyinjiao, is a point studied for period pain and in labor, and one often cautioned in pregnancy. This page is information only. It does not tell you to press, needle or stimulate any point to treat a condition or to start labor.

Urgent first

If you are pregnant and have worrying symptoms, contact your maternity provider or emergency services now (911 in the United States). Do not use acupuncture or acupressure to postpone seeing a health care provider.[1]

Traditional description

In the traditional framework, SP6 belongs to the Spleen channel (see Meridians and Channels in Acupuncture). The Chinese terms are traditional concepts, not the spleen organ as biomedicine describes it. Standard descriptions place SP6 on the inner side of the lower leg, above the ankle bone, just behind the shin bone.[2]

What research has found

4 items reportedMost serious first. The colour shows how severe each report was.

  1. Period pain (19 studies, 1,171 people; acupressure and acupuncture at SP6)

    Unclear

    Reduced pain scores, with considerable differences between studies.[6]

    Promising but limited: the review mixed randomized and non-randomized designs.[6]

  2. Labor pain, acupressure (37 studies)

    Unclear

    Reduced pain compared with touch, sham and no intervention; SP6 had more effect than LI4 in this update.[7]

    Moderate to low certainty; possible publication bias.[7]

  3. Labor pain, Cochrane review (28 trials, 3,960 women)

    Unclear

    Acupuncture may make little or no difference to pain intensity compared with sham; acupressure results were mostly very low certainty.[8]

    Mixed. No trial was at low risk of bias on all measures.[8]

  4. Starting labor (10 trials, 1,432 people)

    Unclear

    No significant difference from sham or usual care in onset of spontaneous labor.[9]

    Moderate to very low quality; no good evidence of benefit.

One 2025 Chinese trial combined SP6, LI4 and LR3 in first-time mothers, compared with routine care, and reported a lower cesarean rate and shorter labor.[10] Because points were combined and the control group got only routine nursing, it cannot show what SP6 itself did.[10]

Many acupressure and acupuncture trials cannot be blinded, so expectation can raise reported relief. See Acupressure in Labor and Pregnancy and Acupuncture for Menstrual Pain and Endometriosis.

Frequently asked questions

What is SP6 or Sanyinjiao?

A point in the traditional Spleen channel, described on the inner lower leg above the ankle bone behind the shin bone.[2]

Is SP6 unsafe in pregnancy?

It is generally treated as a point to avoid for needling in pregnancy because of a theoretical concern about contractions.[3] The wider "forbidden points" idea is debated and not proven.[4]

Does SP6 help period pain?

A 2024 review of 19 studies found lower pain scores with acupressure or acupuncture at SP6, with considerable differences between studies.[6]

Can SP6 start labor?

A 2025 review of 10 trials found no significant difference in onset of spontaneous labor against sham or usual care.[9] Do not try to induce labor yourself.

Should I stop my medicine or care plan?

No. Use this page to prepare questions for your clinician, not to change treatment.[1]

More details: evidence, limits and cautions

The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.

Pregnancy caution

SP6 is generally considered contraindicated for needling in pregnancy, because of concern that stimulating it might provoke preterm uterine contractions, according to a 2026 clinical-algorithm paper on pregnancy sleep problems.[3] That is a stated precaution, not a proven harm.

The wider idea of "forbidden points" is debated. One 2011 discussion paper describes recommendations ranging from avoiding these points at any time in pregnancy to saying they are not contraindicated in normal pregnancy.[4] Another notes that the concern is long-standing, but the small number of available publications seems to show it is not correct, and calls for animal research and a systematic review.[5] Because the question is unsettled, the sensible approach is to treat pregnancy as a reason to speak with your maternity provider and a qualified acupuncturist before any acupuncture or acupressure. See Points Commonly Cautioned in Pregnancy and Acupuncture in Pregnancy.

Other cautions

Needle acupuncture can cause serious harm when not delivered properly.[1] The NHS notes it may not be safe with blood thinning medicine or bleeding risk, or with skin infection.[11] Severe period pain that is new or worsening deserves medical assessment first. See Acupuncture Side Effects and Precautions.

References
  1. National Center for Complementary and Integrative Health (NCCIH), Acupuncture: Effectiveness and Safety. Read 2026-10-22.
  2. Ultrasound-guided stellate ganglion acupuncture for chronic insomnia disorder using fNIRS: study protocol. Front Neurol 2026 (cited only for the standard description of where SP6 is located). Read 2026-10-22.
  3. Zhao FY, Yue LP, Ho YS, et al. Translating evidence into obstetric care: developing a best practice-informed stepped-care clinical algorithm for the management of gestational insomnia. Nat Sci Sleep 2026. Read 2026-10-22.
  4. Betts D, Budd S. "Forbidden points" in pregnancy: historical wisdom? Acupunct Med 2011. Read 2026-10-22.
  5. da Silva AV, Nakamura MU, da Silva JB. "Forbidden points" in pregnancy: do they exist? Acupunct Med 2011. Read 2026-10-22.
  6. Ravi P, Boopalan D, Vijayakumar V, et al. Effect of Sanyinjiao (Spleen-6) acupoint for pain management in primary dysmenorrhea: an updated systematic review and meta-analysis. Med Acupunct 2024. Read 2026-10-22.
  7. Larki M, Karimi L, Jahanfar S, et al. Unveiling the latest evidence: an updated systematic review and meta-analysis and GRADE assessment on the effectiveness of acupressure in managing labor pain. BMC Complement Med Ther 2025. Read 2026-10-22.
  8. Smith CA, Collins CT, Levett KM, et al. Acupuncture or acupressure for pain management during labour. Cochrane Database Syst Rev 2020. Read 2026-10-22.
  9. Chen A, Zhang J, Gao D, et al. Acupuncture for induction of labor in uncomplicated term pregnancies and the role of the acupoint selection: a systematic review and meta-analysis. Acta Obstet Gynecol Scand 2025. Read 2026-10-22.
  10. Cheng Z, Song Z, Feng X, et al. Effect of acupuncture at Hegu (LI4), Taichong (LR3) and Sanyinjiao (SP6) on labor stage in primiparas. Zhongguo Zhen Jiu 2025 (abstract read; article in Chinese). Read 2026-10-22.
  11. NHS, Herbal medicines and complementary therapies. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.