UMIN-CTR Clinical Trial

Public title

A study comparing childbirth with and without a single spinal injection for labor pain relief

Acronym

Single-Injection Labor Analgesia Study

Scientific Title

Study of Labor Analgesia Using Single-Shot Spinal Analgesia

Scientific Title:Acronym

SAB Labor Study

Region

Japan

Condition

Vaginal delivery in women with singleton, cephalic pregnancies

Classification by specialty

Obstetrics and Gynecology	Anesthesiology	Adult

Classification by malignancy

Others

Genomic information

NO

Narrative objectives1

This retrospective observational study aims to evaluate the clinical utility and safety of single-shot spinal analgesia (SAB) for labor analgesia. Maternal and neonatal outcomes, including total labor duration, labor progression, operative vaginal delivery, and maternal adverse events, will be compared between women who received SAB and those who underwent vaginal delivery without neuraxial labor analgesia at Nadeshiko Ladies Hospital. Patient satisfaction will also be assessed using previously collected routine clinical questionnaire data from women who received SAB.

Basic objectives2

Safety,Efficacy

Basic objectives -Others

Trial characteristics_1

Exploratory

Trial characteristics_2

Pragmatic

Developmental phase

Not applicable

Primary outcomes

Total labor duration (minutes), defined as the time from spontaneous onset of labor or initiation of labor induction to delivery. The duration will be calculated from existing medical and delivery records and compared between the single-shot spinal analgesia (SAB) group and the conventional delivery group.

Key secondary outcomes

Secondary outcomes include the durations of the first and second stages of labor; time from SAB administration to full cervical dilation and delivery; use, type, and frequency of rescue analgesia; rates of vacuum-assisted delivery, forceps delivery, and emergency cesarean delivery; maternal blood loss; and maternal adverse events, including hypotension, nausea and vomiting, pruritus, urinary retention, fever, postpartum hemorrhage, post-dural puncture headache, and neurological complications. Neonatal outcomes include birth weight, 1- and 5-minute Apgar scores, umbilical arterial blood pH, and NICU admission. The proportions of neonates with umbilical arterial blood pH below 7.2 and 1- or 5-minute Apgar scores below 7 will also be assessed. Patient satisfaction will be evaluated using previously collected routine clinical questionnaires in the SAB group.

Study type

Observational

Basic design

Randomization

Randomization unit

Blinding

Control

Stratification

Dynamic allocation

Institution consideration

Blocking

Concealment

No. of arms

Purpose of intervention

Type of intervention

Interventions/Control_1

Interventions/Control_2

Interventions/Control_3

Interventions/Control_4

Interventions/Control_5

Interventions/Control_6

Interventions/Control_7

Interventions/Control_8

Interventions/Control_9

Interventions/Control_10

Age-lower limit

20

years-old

<=

Age-upper limit

51

years-old

>

Gender

Female

Key inclusion criteria

1. Women aged 20 years or older who delivered at Nadeshiko Ladies Hospital between April 1, 2025, and July 31, 2026.
2. Women with singleton, cephalic pregnancies who underwent vaginal delivery at 36 weeks of gestation or later.
3. Women who received single-shot spinal analgesia (SAB) for labor analgesia or women who underwent vaginal delivery without neuraxial labor analgesia, including SAB, epidural analgesia, or combined spinal-epidural analgesia.

Key exclusion criteria

1. History of previous cesarean delivery.
2. Multiple pregnancy, breech presentation, delivery before 36 weeks of gestation, or intrauterine fetal death.
3. Intrauterine fetal growth restriction or suspected fetal abnormalities identified prenatally.
4. Maternal BMI of 30 kg/m^2 or higher, hypertensive disorders of pregnancy requiring antihypertensive medication, or poorly controlled gestational diabetes mellitus (defined as a 2-hour postprandial blood glucose level of 150 mg/dL or higher).
5. Labor analgesia other than single-shot spinal analgesia, including epidural analgesia, combined spinal-epidural analgesia, or paracervical block.
6. Missing data for the primary outcome.

Target sample size

80

Name of lead principal investigator

1st name	Yoshinori
Middle name
Last name	Kamiya

Organization

Gifu University Graduate School of Medicine

Division name

Department of Anesthesiology and Pain Medicine

Zip code

501-1194

Address

1-1 Yanagido, Gifu, Gifu 501-1194, Japan

TEL

058-230-6404

Email

kamiya.yoshinori.p2@f.gifu-u.ac.jp

Name of contact person

1st name	Yoshinori
Middle name
Last name	Kamiya

Organization

Gifu University Graduate School of Medicine

Division name

Department of Anesthesiology and Pain Medicine

Zip code

501-1194

Address

1-1 Yanagido, Gifu, Gifu 501-1194, Japan

TEL

058-230-6404

Homepage URL

Email

yoshinori.kamiya@gmail.com

Institute

Gifu University

Institute

Department

Personal name

Yoishinori Kamiya

Organization

Gifu University

Organization

Division

Category of Funding Organization

Self funding

Nationality of Funding Organization

Japan

Co-sponsor

Nadeshiko Ladies Hospital

Name of secondary funder(s)

Organization

Ethics Committee of the Graduate School of Medicine, Gifu University

Address

1-1 Yanagido, Gifu, Gifu 501-1194, Japan

Tel

058-230-6059

Email

rinri@t.gifu-u.ac.jp

Secondary IDs

NO

Study ID_1

Org. issuing International ID_1

Study ID_2

Org. issuing International ID_2

IND to MHLW

Institutions

なでしこレディースホスピタル（兵庫県神戸市）

Date of disclosure of the study information

2026

Year

10

Month

26

Day

URL releasing protocol

Publication of results

Unpublished

URL related to results and publications

Number of participants that the trial has enrolled

80

Results

Results date posted

Results Delayed

Results Delay Reason

Date of the first journal publication of results

Baseline Characteristics

Participant flow

Adverse events

Outcome measures

Plan to share IPD

IPD sharing Plan description

Recruitment status

No longer recruiting

Date of protocol fixation

2026

Year

09

Month

06

Day

Date of IRB

2026

Year

09

Month

24

Day

Anticipated trial start date

2026

Year

09

Month

24

Day

Last follow-up date

2026

Year

09

Month

30

Day

Date of closure to data entry

Date trial data considered complete

2026

Year

09

Month

30

Day

Date analysis concluded

Other related information

This is a retrospective observational cohort study conducted at Nadeshiko Ladies Hospital.

The study population consists of women aged 20 years or older who delivered between April 1, 2025, and July 31, 2026. All eligible cases of singleton, cephalic vaginal delivery at 36 weeks of gestation or later will be included according to the protocol-defined inclusion and exclusion criteria. No random sampling will be performed.

Maternal and neonatal outcomes will be compared between women who received single-shot spinal analgesia (SAB) as part of routine clinical care and women who underwent vaginal delivery without neuraxial labor analgesia.

Existing medical, delivery, anesthesia, and nursing records and previously collected routine patient satisfaction questionnaires will be reviewed retrospectively.

The primary outcome is total labor duration. Secondary outcomes include the duration of the first and second stages of labor, operative vaginal delivery, maternal blood loss, maternal adverse events, neonatal outcomes, and patient satisfaction in the SAB group.

No treatment allocation or additional intervention will be performed for research purposes. An opt-out procedure will be used.

The period covered by the source clinical records began before finalization of the study protocol and registration in UMIN-CTR. Therefore, this is a retrospectively registered observational study.

Registered date

2026

Year

10

Month

25

Day

Last modified on

2026

Year

10

Month

25

Day

Link to view the page

Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000072526