Trial of Ultrasound-guided Rotation for Normalizing Head Position

Number of participants with successful fetal position correction

Number of participants with successful fetal position correction assessed by vaginal examination Revised fetal position refers to fetal cephalic position converted from abnormal presentations (occiput posterior position, occiput transverse position) to delivery-favorable positions including occiput anterior position, left occiput anterior position, or right occiput anterior position following clinical intervention.Fetal position is assessed via vaginal examination performed by uniformly trained obstetricians or midwives.Successful correction is defined as fetal occiput rotating to occiput anterior, left occiput anterior, or right occiput anterior after intervention. Correction is considered unsuccessful if the fetus remains in occiput posterior, occiput transverse, or other unfavorable fetal positions.

Time frame: Immediately after completion of intervention, upon entry into the second stage of labor, and at fetal delivery

Success Rate of Manual Fetal Head Rotation

The success rate of manual fetal head rotation refers to the proportion of cases in which the fetal position is successfully converted to a position conducive to vaginal delivery following manual rotation of the fetal head. The attending obstetrician performing the operation documents the pre-procedural fetal position, post-procedural fetal position, procedural outcome, requirement for repeat rotation, and occurrence of related adverse events. The maneuver is defined as successful if the fetal head is rotated from occiput posterior or occiput transverse position to occiput anterior position without immediate reversion to an abnormal position during subsequent labor. It is classified as a failed attempt when positional rotation cannot be achieved, the fetal position reverts rapidly after manipulation, or

Time frame: This indicator is recorded immediately after the completion of the procedure, and the final fetal position is reconfirmed at fetal delivery.

Intrapartum Fever

Intrapartum fever is defined as elevated maternal body temperature occurring from the onset of labor to fetal delivery. The same temperature measurement method (axillary, tympanic or oral thermometry) is adopted throughout the study; the maximum body temperature and its onset time are documented accordingly. Intrapartum fever is defined as an intrapartum temperature ≥38.0 °C. Suspected chorioamnionitis/intrauterine infection refers to clinical manifestations suggestive of intrauterine infection emerging during labor. This outcome is comprehensively assessed by the attending physician based on maternal body temperature, fetal heart rate, maternal heart rate, uterine tenderness, amniotic fluid characteristic

Time frame: Routine maternal temperature monitoring commences at labour onset, with an inspection interval of 2 to 4 hours; monitoring continues until 24 hours after childbirth.

Mode of Delivery

Mode of delivery is defined as the definitive delivery modality of parturients, which is abstracted from delivery records and operative notes immediately after childbirth completion, and categorized into spontaneous vaginal delivery, cesarean section and forceps-assisted vaginal delivery. Final fetal position at delivery refers to the fetal cephalic position upon fetal expulsion, determined by birth attendants according to the direction of fetal head delivery, occipital bone location and delivery documentation, and documented as occiput anterior, occiput posterior or occiput transverse position.

Time frame: It is abstracted from delivery records and operative notes immediately after childbirth completion

Forceps Delivery

Forceps delivery is defined as instrumental extraction with obstetric forceps performed for indicated clinical reasons during labor. This variable is abstracted from delivery records and forceps procedure documentation; cases with documented forceps application are coded as "Yes", whereas those without forceps use are coded as "No".

Time frame: Right after childbirth

2-hour Postpartum Blood Loss

Two-hour postpartum blood loss is defined as the total volume of vaginal bleeding from fetal delivery to 2 hours after childbirth. This indicator is quantified by quantitative measurement approaches, including blood collection bag collection, gravimetric method and dressing weight conversion method.

Time frame: From fetal delivery to 2 hours after childbirth

Total Duration of Labor

Total duration of labor is defined as the total time elapsed from the onset of regular uterine contractions to fetal delivery. It is calculated by extracting the initiation time of regular contractions, time of complete cervical dilatation and fetal delivery time from partograms, nursing records and inpatient medical records, with the unit of hours.

Time frame: From the onset of childbirth to immediate postpartum completion, assessed at delivery

Episiotomy

Episiotomy refers to surgical perineal incision performed for clinical indications during vaginal delivery. Data are abstracted from delivery records and documented as "Yes/No"; when applicable, the incision type is further specified as left mediolateral, right mediolateral or midline episiotomy.

Time frame: Immediately after childbirth (at delivery)

The rate of Severe perineal laceration

Severe perineal laceration is defined as third- or fourth-degree perineal tear involving the anal sphincter or rectal mucosa. Following fetal delivery and prior to perineal repair, obstetricians conduct physical examination of the perineum, vagina and anal sphincter; digital rectal examination is performed when needed to confirm the extent of injury.The rate is defined as the count of severe perineal laceration cases divided by the total number of vaginal deliveries, then multiplied by 100%.

Time frame: immediately after delivery

Perineal Hematoma

Perineal hematoma is localized blood collection within the vulva, vagina or perineum after delivery, diagnosed by midwives or physicians based on inspection, palpation and maternal clinical manifestations, with ultrasonography arranged for confirmation as required. A case is marked "Yes" if localized swelling, pain, tenderness or violaceous mass is present with a confirmed clinical diagnosis of perineal or vaginal hematoma; the maximum diameter of hematoma (in cm) is recommended to be documented additionally.

Time frame: Within 24 hours after delivery

Postpartum Fever

Postpartum fever is defined as elevated maternal body temperature occurring after fetal delivery.The maximum body temperature and its onset time are documented. Postpartum fever is preliminarily defined as body temperature ≥38.0 °C. To eliminate interference from transient physiological temperature fluctuations shortly after childbirth, an alternative diagnostic criterion can be adopted: temperature ≥38.0 °C beyond 24 hours postpartum, or two consecutive temperature readings ≥38.0 °C.

Time frame: Daily assessments, starting immediately after delivery (Day 0), through hospital discharge (1-day postpartum for vaginal delivery, 3-day postpartum for cesarean section)

Amniotic Fluid Characteristics

Amniotic fluid characteristics include color, clarity and odor of amniotic fluid, as well as the presence of meconium or blood, which are assessed and documented by midwives or delivery clinicians through gross visual examination after fetal delivery. The findings are categorized as clear, grade Ⅰ staining, grade Ⅱ staining and grade Ⅲ staining.

Time frame: Data is extracted from delivery records immediately postpartum.

Proportion of Participants with Abnormal Umbilical Cord Conditions

Multiple umbilical cord abnormalities (nuchal cord, umbilical cord torsion, true umbilical knot, short umbilical cord) are clinically assessed and documented by birth attendants at delivery. All abnormal findings are aggregated to report the overall proportion of participants with abnormal umbilical cord conditions.

Time frame: Immediately postpartum

Number of participants with incomplete delivered placenta

After expulsion of the placenta, midwives or obstetric clinicians inspect the maternal surface, fetal surface, fetal membranes and umbilical cord insertion site. The judgement of incomplete placenta is completed by clinical macroscopic examination

Time frame: Within 30 minutes following the expulsion of the delivered placenta

Birth Weight of Neonates

Neonatal birth weight is defined as the nude body weight measured for the first time after delivery. Weight measurement is completed within 1 hour postpartum using a calibrated electronic infant scale after removing clothes, diapers and other accessories, recorded in grams with an accuracy of 10 g. Macrosomia is diagnosed based on birth weight; infants with birth weight ≥4000 g are classified as macrosomic infants.

Time frame: Data is extracted from delivery records immediately postpartum.

1-minute and 5-minute Neonatal Apgar Scores

The 1-minute and 5-minute Apgar scores represent comprehensive assessments of neonatal heart rate, respiration, muscle tone, reflex irritability and skin color performed at 1 and 5 minutes after birth, respectively. Each item is scored from 0 to 2 points, yielding a total score ranging from 0 to 10. Scores are evaluated and documented by birth attendants or neonatologists in accordance with standardized Apgar scoring criteria.

Time frame: 1 and 5 minutes after birth

Umbilical Arterial Blood Gas pH of Neonates

Neonatal umbilical arterial blood gas pH refers to the pH value obtained from blood gas analysis of umbilical arterial blood sampled after fetal delivery, which is used to assess the neonatal acid-base status at birth. The umbilical cord is double-clamped as soon as possible following delivery; blood specimens are collected from the umbilical artery and submitted for detection by a blood gas analyzer within 15 to 30 minutes after birth.

Time frame: Within 15 to 30 minutes after birth

Neonatal Resuscitation

Neonatal resuscitation is defined as any resuscitative intervention administered after birth due to abnormalities in respiration, heart rate, muscle tone or other conditions. This variable is abstracted from neonatal resuscitation records, covering initial stabilization, airway suctioning, bag-mask ventilation, endotracheal intubation, chest compressions, and epinephrine administration.

Time frame: Data is extracted from delivery records immediately postpartum.

Caput Succedaneum Area

Caput succedaneum area denotes the scope of scalp soft tissue edema forming caput succedaneum in newborns after delivery. Immediately after birth, trained research personnel measure the maximum longitudinal diameter and the perpendicular maximum transverse diameter of the lesion with a flexible measuring tape. A simplified area calculation formula is applied: Caput succedaneum area = maximum longitudinal diameter × maximum transverse diameter, with the unit of cm².

Time frame: Immediately after birth

Occipitofrontal Circumference (Head Circumference)

Neonatal head circumference is defined as the maximal cranial perimeter. Measurement is completed within 24 hours after birth using an inelastic flexible tape wrapped around the skull through the superior margin of the supraorbital ridges and the most prominent point of the occipital protuberance, with centimeters as the measuring unit. Repeat measurement is recommended after resolution when obvious caput succedaneum or cranial molding exists.

Time frame: within 24 hours after birth

Abdominal Circumference

Neonatal abdominal circumference refers to the maximum abdominal perimeter. With the newborn in supine position and resting quietly, measurement is performed using an inelastic flexible tape encircling the abdomen at the umbilical level, recorded in centimeters (cm).

Time frame: Data is extracted from delivery records immediately postpartum.

Neonatal Birth Length

Birth length is the crown-heel length measured with the newborn in supine position. Measurement is finished within 24 hours after birth using an infant length board by two examiners. The infant's head is fixed and lower extremities fully extended to measure the distance from the top of the head to the heel, with centimeters (cm) as the unit.

Time frame: Within 24 hours after birth

Postpartum childbirth experience

Postpartum childbirth experience refers to the parturient's subjective perception of the labor process, including sense of safety, pain control, participation in decision-making, healthcare provider support, perceived control over childbirth and overall satisfaction. This indicator is assessed via qualitative interviews within 24-72 hours after delivery or prior to hospital discharge.A five-category Likert scale is adopted for satisfaction rating, consisting of five grades: Very Dissatisfied, Dissatisfied, Neutral, Satisfied and Very Satisfied.

Time frame: This indicator is assessed via qualitative interviews within 24-72 hours after delivery or prior to hospital discharge.

Length of Hospital Stay

Length of hospital stay is defined as the total duration from maternal admission to hospital discharge. It is calculated post-discharge based on admission and discharge dates recorded in the hospital information system, with days as the unit.

Time frame: Length of hospital stay is defined as the total number of calendar days from the date of hospital admission to the date of hospital discharge for the index delivery, calculated as discharge date minus admission date（≤42 days after delivery）.

Hospitalization Costs

Hospitalization costs refer to the total medical expenses incurred by the parturient during the current delivery-related hospitalization. After final billing upon discharge, researchers extract relevant data from the hospital charging system or front sheet of medical records, denominated in Chinese Yuan (CNY). According to research requirements, total costs can be further categorized into total hospitalization expense, out-of-pocket expense, pharmaceutical cost, examination fee, and surgical procedural cost.

Time frame: Hospitalization costs refer to all medical expenses incurred during the index delivery hospitalization from admission to discharge, covering all items charged by the hospital for maternal inpatient care related to childbirth（≤42 days after delivery）.

Postpartum Blood Loss within 24 Hours

Postpartum blood loss within 24 hours is defined as the total vaginal blood loss from fetal delivery to 24 hours postpartum. Data are documented via a combination of blood collection pouch measurement, gravimetric method, nursing records and clinical estimation, with priority given to objective quantitative measurement; the unit is milliliters (mL). Postpartum hemorrhage is diagnosed when cumulative blood loss reaches ≥500 mL within 24 hours after vaginal delivery or ≥1000 mL following cesarean delivery.

Time frame: From fetal delivery to 24 hours postpartum

Postpartum White Blood Cell (WBC) Count

Postpartum WBC count refers to the white blood cell count in peripheral blood. Venous blood samples are collected 24-48 hours postpartum and tested via routine complete blood count in the hospital clinical laboratory, with the unit of ×10⁹/L. Repeat testing can be arranged when clinical infection is suspected.

Time frame: 24-48 hours postpartum

Postpartum Hemoglobin

Postpartum hemoglobin denotes the hemoglobin concentration in peripheral blood. Venous blood sampling for routine complete blood count is recommended within 24-48 hours postpartum, measured in g/L. This indicator is recorded as a continuous variable.

Time frame: 24-48 hours postpartum

Perineal Edema

Perineal edema is characterized by swelling, tension, pain or localized tenderness of perineal tissues following delivery. Assessment via visual inspection and palpation by midwives or physicians is recommended at 24 hours postpartum, 48 hours postpartum and prior to hospital discharge.

Time frame: At Day 1 after neonatal birth, Day 2 after neonatal birth and within 72 hours after neonatal birth before hospital discharge assessment

Breastfeeding Status

Breastfeeding status reflects the feeding mode of neonates during maternal hospitalization. Relevant data are collected from nursing records and maternal interviews at 24 hours postpartum and before discharge, which are classified into exclusive breastfeeding, mixed feeding, formula feeding and mother-infant separation.

Time frame: At Day 1 after neonatal birth and within 72 hours after neonatal birth

NICU Transfer

NICU transfer refers to the admission of a newborn to the neonatal intensive care unit due to clinical necessity after birth. Relevant data are extracted from neonatal medical records, transfer documents and NICU admission records from birth until discharge; cases with documented NICU admission or transfer are coded as "Yes".

Time frame: NICU transfer is defined as any transfer of the live newborn to the neonatal intensive care unit for specialized monitoring or therapeutic intervention within the initial postpartum hospitalization（≤42 days after delivery）.

Birth Trauma in Neonates

Neonatal birth trauma is defined as injuries occurring during delivery related to mechanical compression, obstetric manipulation or birth canal squeezing. Physical examination is performed by neonatologists from immediately after birth to pre-discharge, with supplementary imaging examinations conducted when necessary. Cases diagnosed by neonatologists with cephalohematoma, clavicular fracture, brachial plexus injury, facial nerve injury, intracranial hemorrhage, skin laceration or soft tissue injury are documented as neonatal birth trauma.

Time frame: Starting from the day of delivery until 42 days after birth.

Neonatal Complications

Neonatal complications refer to neonatal diseases or abnormal conditions requiring clinical evaluation or treatment occurring during postnatal hospitalization. Data are extracted from neonatal progress notes, medical orders, laboratory and imaging results as well as discharge diagnoses. Common complications consist of neonatal asphyxia, respiratory distress, hypoglycemia, hyperbilirubinemia, confirmed or suspected infection, feeding intolerance, meconium aspiration syndrome and acidosis.

Time frame: Starting from the day of delivery until 42 days after birth.

Mechanical Ventilation Support

Mechanical ventilation is defined as ventilatory support administered to neonates for respiratory insufficiency after birth. Relevant information is extracted from neonatal resuscitation records, NICU medical documents and physician orders from birth to hospital discharge. Infants receiving either non-invasive or invasive mechanical ventilation are marked as "Yes". Further classification into CPAP, non-invasive positive pressure ventilation and invasive endotracheal mechanical ventilation is recommended.

Time frame: Starting from the day of delivery until 42 days after birth.

Neonatal Length of Hospital Stay

Neonatal length of hospital stay is defined as the hospitalization duration from neonatal birth/admission to discharge, which is calculated based on the infant's admission and discharge dates and recorded in days.

Time frame: At neonatal discharge

Neonatal Hospitalization Expenses

Neonatal hospitalization expenses refer to the total medical costs incurred during the current admission. Data are collected from the hospital billing system or hospital settlement list after discharge billing, measured in Chinese Yuan (CNY).

Time frame: Neonatal hospitalization costs refer to all medical expenses incurred for live newborns during the index delivery hospitalization or any neonatal readmission within 42 days postpartum.

Puerperal Infection

Puerperal infection refers to genital tract or systemic infection occurring during the puerperium, including endometritis, wound infection, urinary tract infection, mastitis and other delivery-related infectious diseases. Data are collected via outpatient follow-up, telephone interview and electronic medical record review from discharge to 42 days postpartum. Researchers make comprehensive judgments based on maternal complaints, body temperature, clinical diagnosis, antibiotic administration, laboratory results and inpatient/outpatient documents. Cases clinically diagnosed with puerperal infection or receiving antibiotic therapy for infection within 42 days postpartum are coded as "Yes".

Time frame: From discharge to 42 days postpartum

Rate of Poor Wound Healing

Poor wound healing is defined as delayed healing, erythema, exudation, wound dehiscence, infection or requirement for secondary intervention involving episiotomy incision, sutured perineal laceration or cesarean abdominal incision. This indicator is assessed before discharge and at the 42-day postpartum follow-up through outpatient physical examination, medical record review or telephone follow-up, with on-site evaluation by obstetricians arranged when necessary. Cases presenting with marked incision redness and tenderness, purulent discharge, wound dehiscence or delayed healing, or requiring debridement, dressing change and anti-infective treatment are classified as poor wound healing.This rate equals the count of participants with poor postpartum wound healing divided by the total number of delivered participants, multiplied by 100%.

Time frame: Within 72 hours after neonatal birth and at day 42 following childbirth

Breastfeeding Status within 42 Days Postpartum

Data on breastfeeding status within 42 days after delivery are collected from mothers via telephone follow-up, online questionnaires or outpatient revisit interviews, which are categorized into exclusive breastfeeding, mixed feeding, formula feeding and mother-infant separation.

Time frame: 42 Days Postpartum