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Cephalic presentation

Cephalic presentation refers to the orientation of the fetus in the uterus during late pregnancy and labor in which the head is the presenting part, positioned downward toward the cervix and birth canal. This is the most common fetal position at term, occurring in approximately 96% to 97% of singleton pregnancies, as non-cephalic (breech) presentations account for only 3% to 4%.^[1] It is considered the ideal position for vaginal delivery because the fetal head, with its relatively compressible skull and smallest presenting diameter in the flexed state, facilitates passage through the maternal pelvis. Within cephalic presentations, subtypes are distinguished by the degree of flexion or extension of the fetal head relative to the neck. The vertex presentation, characterized by full flexion of the head with the occiput (back of the head) as the leading part, is the predominant subtype and allows for the narrowest suboccipitobregmatic diameter (approximately 9.5 cm) to engage the pelvis.^[2] Less common variants include brow presentation, where the head is partially extended and the forehead leads (presenting diameter about 13 cm, often requiring cesarean delivery due to increased risk of arrest), face presentation with further extension and the mentum (chin) as the presenting part.^[2] These atypical cephalic positions together comprise less than 1% of term labors and may arise from factors such as fetal anomalies, uterine abnormalities, or polyhydramnios.^[2] Fetal presentation is typically assessed clinically via Leopold's maneuvers—abdominal palpation to determine lie, presentation, and position—or confirmed by ultrasound, which provides precise visualization of the fetal attitude and orientation.^[3] By 32 to 36 weeks of gestation, the majority of cephalic presentations stabilize, though spontaneous version can occur; if a non-cephalic position persists, external cephalic version (ECV) may be offered around 37 weeks to manually rotate the fetus to cephalic presentation, reducing the likelihood of cesarean birth.^[4] Overall, cephalic presentation supports efficient labor progression, lower maternal and neonatal morbidity, and higher rates of spontaneous vaginal delivery compared to malpresentations.^[5]

Overview

Definition

Cephalic presentation refers to the orientation of the fetus in the uterus during late pregnancy and labor in which the head is the presenting part, positioned toward the cervix and birth canal.^[6] This is the most common orientation, occurring in approximately 96-97% of term pregnancies, as the majority of fetuses spontaneously rotate to a head-down position by late gestation.^[7] In cephalic presentation, the presenting part is the fetal head, and the denominator—a fixed bony reference point used to describe the position—is the occiput (back of the head) in vertex presentations, the mentum (chin) in face presentations, or the bregma (area of the forehead between the frontal and parietal bones) in brow presentations.^[2]^[8] This contrasts with breech presentation, where the buttocks or feet enter the pelvis first, or transverse lie, which may result in the shoulder as the presenting part.^[9] Cephalic presentation facilitates vaginal delivery and is linked to lower risks of complications such as prolonged labor or cesarean section compared to other presentations.^[9]

Clinical Significance

Cephalic presentation holds substantial clinical importance in obstetrics as it optimizes the conditions for vaginal delivery, minimizing risks to both the mother and fetus. In the vertex subtype, which is the most common form, the fetal head flexes to present the suboccipitobregmatic diameter—approximately 9.5 cm—the smallest anteroposterior measurement of the fetal head at term. This configuration allows for smoother engagement and passage through the maternal pelvis, as the presenting part aligns efficiently with the pelvic inlet and outlet.^[2] The moldability of the fetal skull further enhances these advantages; the cranial bones, connected by compressible sutures and fontanelles, can overlap and adapt to the contours of the birth canal during labor, effectively reducing the head's diameter and facilitating progression without excessive force. This adaptability is crucial in facilitating progression through the birth canal during labor. Consequently, cephalic presentations are linked to higher rates of successful spontaneous vaginal births, with reduced maternal morbidity. From a fetal perspective, this presentation correlates with lower perinatal morbidity and mortality compared to non-cephalic positions, as it decreases the risk of birth asphyxia, trauma, and neonatal intensive care admission. Unresolved malpresentations, by contrast, elevate the probability of cesarean delivery, which carries its own procedural risks such as infection and anesthesia complications, underscoring the protective role of cephalic positioning.^[10]^[11]^[12] Historically, cephalic presentation has been regarded as the ideal and default orientation for spontaneous vaginal birth since ancient obstetrics, with non-cephalic deliveries often viewed as portents of danger in early medical texts and cultural practices.^[13]

Mechanism and Engagement

Fetal Positioning

Fetal lie describes the relationship between the long axis of the fetus and the long axis of the uterus. A longitudinal lie, in which the fetal spine is parallel to the mother's spine, is required for cephalic presentation, allowing the head to enter the pelvis first. In contrast, a transverse lie positions the fetal spine perpendicular to the mother's spine, which precludes vaginal delivery in a cephalic manner and often necessitates cesarean section.^[14]^[15] Fetal attitude refers to the posture or degree of flexion of the fetal body parts, particularly the head and limbs. In cephalic presentation, the optimal attitude is one of full flexion, where the fetal head is sharply flexed with the chin tucked against the chest, the arms and legs folded toward the body, and the back curved. This flexion minimizes the presenting diameter of the head to approximately 9.5 cm (suboccipitobregmatic), facilitating passage through the maternal pelvis. Deflexed attitudes, such as partial extension, result in larger diameters and potential complications.^[2]^[11]^[16] Fetal station quantifies the level of descent of the presenting part into the maternal pelvis, measured relative to the ischial spines as a reference point. The scale ranges from -5 (the presenting part is 5 cm above the ischial spines, high in the pelvis) to +5 (the presenting part has passed the perineum and is crowning). Engagement occurs at 0 station, where the widest transverse diameter of the presenting part aligns with the ischial spines, marking the transition from the pelvic inlet to the midpelvis.^[17]^[18] In cephalic presentations, the orientation of the fetal head is denoted using specific anatomic landmarks known as denominators. For vertex presentation, the occiput (posterior fontanelle) serves as the denominator; for brow presentation, the bregma or frontum (forehead); and for face presentation, the mentum (chin). These landmarks reference the position of the head relative to the maternal pelvis, aiding in the precise description of rotational movements during labor.^[16]^[19]^[20]

Engagement Process

The engagement process in cephalic presentation refers to the initial descent of the fetal head into the maternal pelvic inlet, marking the transition from the abdominal cavity to the birth canal. This dynamic phase is primarily driven by the forces of uterine contractions, which generate pressure from the fundus to propel the fetus downward, combined with the hydrostatic pressure exerted by amniotic fluid surrounding the fetus. As the presenting part encounters the resistance of the pelvic architecture, particularly the pelvic floor and inlet, the fetal head undergoes flexion, reducing its presenting diameter from the larger occipitofrontal (approximately 11.5 cm) to the smaller suboccipitobregmatic (approximately 9.5 cm), facilitating smoother passage through the bony pelvis.^[16]^[21]^[2] Engagement typically occurs in the late third trimester, around 36 to 38 weeks of gestation in primigravida (first-time mothers), where the biparietal diameter of the fetal head descends below the plane of the pelvic inlet prior to the onset of labor. In multiparous women, this process often happens later, sometimes concurrent with early labor, due to increased uterine laxity and prior pelvic adaptations from previous deliveries. The timing reflects the balance between fetal growth and maternal pelvic capacity, ensuring the head is positioned for efficient progression during active labor.^[16]^[21] Several factors influence the success and timing of engagement. The maternal pelvic type plays a key role, with the gynecoid pelvis—characterized by a round inlet and spacious midpelvis—being most conducive to head descent compared to narrower android or anthropoid shapes. Fetal size is another determinant; macrosomia (fetal weight exceeding 4,000 g) can delay or impede engagement by increasing the presenting diameter relative to the pelvic dimensions. Additionally, placental position affects this process, as a low-lying placenta such as in placenta previa may exert mechanical resistance, obstructing the fetal head's entry into the pelvis and potentially leading to malposition.^[22]^[21]^[23] Assessment of engagement is commonly performed through Leopold's maneuvers, a series of abdominal palpations conducted in the third trimester or during labor onset. The third maneuver involves grasping the lower uterine segment to evaluate the presenting part's mobility; if the head is fixed and non-ballotable, it indicates engagement, while a floating head suggests incomplete descent. The fourth maneuver assesses the fetal attitude by palpating the contour above the pubic symphysis. These techniques provide a non-invasive overview of positioning but require complementary diagnostic methods for confirmation.^[3]

Classification

Vertex Presentation

Vertex presentation is a subtype of cephalic presentation in which the fetal head is fully flexed, with the chin tucked toward the chest and the occiput serving as the leading part.^[2] This flexion minimizes the presenting diameter of the head, optimizing passage through the maternal pelvis during labor.^[24] The position of the occiput relative to the maternal pelvis defines specific orientations within vertex presentation, including occiput anterior (OA), where the occiput faces the mother's anterior abdomen; occiput posterior (OP), where it faces the mother's sacrum; and occiput transverse (OT), where it aligns laterally with the maternal hips.^[14] The suboccipitobregmatic diameter, extending from the suboccipital region to the bregma, measures approximately 9.5 cm and represents the smallest anteroposterior diameter of the fetal head in vertex presentation, making it particularly suitable for vaginal delivery.^[25] This diameter allows for efficient engagement and descent compared to larger diameters in less flexed positions.^[26] Vertex presentation accounts for about 95% of all term deliveries and the vast majority of cephalic presentations.^[27] Among these, the OA position is the most prevalent and favorable, as it aligns the fetal head optimally with the pelvic curvatures, promoting smoother labor progression.^[5] During the second stage of labor, the fetal head typically enters the pelvis in an OT or oblique position and undergoes internal rotation, driven by uterine contractions and pelvic floor resistance, to align the occiput with the anteroposterior diameter of the pelvic outlet.^[28] This cardinal movement ensures the sagittal suture orients toward the mother's pubic symphysis in OA cases, facilitating expulsion.^[29]

Brow Presentation

Brow presentation is a subtype of cephalic presentation characterized by partial extension of the fetal head, with the forehead (bregma or anterior fontanelle) serving as the presenting part and the mentum (chin) not tucked against the chest. In this position, the fetal neck is midway between flexion and full extension, distinguishing it from the fully flexed vertex presentation.^[2]^[24] The presenting diameter in brow presentation is the occipito-mental (also known as mento-vertical or supra-occipito-mental), measuring approximately 13.5 cm, which represents the largest anteroposterior diameter of the fetal head and significantly exceeds the typical pelvic dimensions, thereby heightening the risk of cephalopelvic disproportion and dystocia.^[24]^[30] This presentation is rare, with an incidence ranging from 1 in 500 to 1 in 1,000 deliveries, though some studies report up to 1 in 4,000; it is often associated with fetal anomalies (such as central nervous system malformations), polyhydramnios, and prematurity.^[2]^[31]^[32] Brow presentation is inherently unstable during labor and frequently converts spontaneously: it may progress to vertex presentation via flexion of the head or to face presentation via further extension, though persistent cases typically lead to prolonged labor and necessitate intervention to promote flexion or extension.^[24]^[33]

Face Presentation

Face presentation, also known as mentum presentation, is a subtype of cephalic presentation characterized by complete hyperextension of the fetal head and neck, resulting in the face—from the forehead to the chin—serving as the presenting part during labor. In this position, the mentum (chin) leads, with the mouth and nose typically identified as the initial presenting structures upon vaginal examination. The engaging diameter in face presentation is the submento-bregmatic, measuring approximately 9.5 cm, which is comparable in size to the suboccipito-bregmatic diameter of vertex presentation but requires specific pelvic accommodation due to the extended posture.^[34]^[35]^[24] The position of the mentum relative to the maternal pelvis significantly influences delivery outcomes. In mentum anterior, the chin is directed toward the pubic symphysis, allowing for potential vaginal delivery as the fetal head can flex and rotate during descent. Conversely, mentum posterior, where the chin faces the sacrum, poses greater challenges because the fetal head cannot achieve the necessary internal rotation to align with the pelvic outlet, often necessitating cesarean section to avoid prolonged labor or complications. Face presentation may arise as an extension from brow presentation when the fetal neck hyperextends further.^[16]^[2]^[24] Face presentation occurs in approximately 1 in 600 to 800 deliveries, representing a rare malpresentation. It is associated with conditions such as polyhydramnios, which allows excessive fetal mobility leading to hyperextension, and certain fetal anomalies, including anencephaly or neck masses that prevent normal flexion. For vaginal delivery in mentum anterior cases, the chin must undergo internal rotation of about one-eighth of a circle anteriorly during the second stage of labor, followed by flexion of the head to facilitate passage through the pelvic outlet; failure of this mechanism typically indicates the need for operative intervention.02560-3/pdf)^[36]^[31]^[35]

Prevalence and Etiology

Prevalence Rates

Cephalic presentation predominates at term, occurring in 96% to 97% of singleton pregnancies worldwide.^[9]^[37] This high rate results from spontaneous versions as gestation advances, with only 3% to 4% of fetuses remaining in non-cephalic positions by delivery.^[25] Earlier in pregnancy, the prevalence is lower; at 28 weeks gestation, approximately 75% of fetuses are cephalic, rising to 94% by 36 weeks.^[38]^[9] Variations in prevalence occur based on maternal and fetal factors. In multiparous women, cephalic presentation tends to engage earlier and more stably compared to nulliparous women, contributing to a slightly higher maintenance of cephalic position at term.^[39] Conversely, multiple gestations show reduced cephalic rates, with only 40% to 45% of twin pregnancies featuring both fetuses in cephalic presentation at term.^[40] Fetal anomalies, such as hydrocephaly or other malformations, are linked to lower cephalic prevalence in affected cases.^[25]^[41] Global data indicate consistency across populations, with minor differences in preterm deliveries where cephalic presentation ranges from 70% to 80% depending on gestational age.^[42] In very preterm births (24-27 weeks), cephalic rates are around 76%, increasing progressively toward term.^[42] Recent trends show a decline in non-cephalic presentations due to increased use of external cephalic version (ECV) for breech cases, indirectly bolstering cephalic prevalence at term to over 97% in settings with routine ECV.^[43]^[44]

Reasons for Predominance

The predominance of cephalic presentation in term pregnancies is largely attributed to biomechanical advantages that facilitate the passage of the fetal head through the maternal pelvis. The fetal head, being the largest part of the body, exhibits significant compressibility due to its fontanelles and cranial sutures, which allow for molding during labor; this adaptability reduces the presenting diameter to approximately 9.4 cm in the flexed vertex position, the smallest possible, enabling it to conform to the curved dimensions of the pelvic inlet (11 cm transverse), midpelvis (12 cm anteroposterior), and outlet (11 cm transverse).^[45]^[46] Additionally, the piriform (pear-shaped) morphology of the uterus positions the heavier fetal head toward the narrower lower uterine segment while accommodating the breech in the wider fundus, promoting flexion and alignment with the pelvic curve for efficient descent.^[47] Physiologically, the increasing volume of amniotic fluid in the second trimester supports fetal mobility, allowing spontaneous version from breech to cephalic presentation through active fetal movements, which become more coordinated by the third trimester as the fetus grows and uterine space diminishes. This process typically results in 95-97% of singletons achieving cephalic presentation by 37 weeks, as the head engages in the pelvis, establishing a stable position that resists reversion due to gravitational and muscular forces.^[48]^[9] From an evolutionary perspective, human bipedalism reshaped the pelvis into a narrower, oval inlet to support upright locomotion, while encephalization increased fetal head size, creating the "obstetrical dilemma" that favors cephalic presentation; this orientation allows the head to rotate 135 degrees during descent—entering occiput posterior and delivering occiput anterior—to navigate the constrained pelvic planes, a adaptation unique to Homo sapiens for accommodating larger brains relative to body size.^[49]^[50] Although cephalic presentation represents the stable equilibrium for most pregnancies, certain factors increase the likelihood of non-cephalic positions, such as prematurity (before 37 weeks), where the smaller fetal size and greater uterine space hinder spontaneous version, occurring in up to 25% of cases at 32 weeks. Multiparity, particularly grand multiparity (parity >4), is associated with a more lax uterine musculature and abdominal wall, reducing the propulsive forces that encourage cephalic alignment, though this risk diminishes as gestational age advances.^[42]^[51]

Diagnosis

Physical Examination

Physical examination plays a crucial role in diagnosing cephalic presentation during antenatal visits and labor, relying on manual palpation and auscultation to assess fetal lie, presentation, position, and engagement without invasive procedures. These methods are non-invasive, bedside techniques performed by trained healthcare providers to evaluate the fetal orientation in the uterus. Cephalic presentation, where the head leads the way, is confirmed through systematic abdominal and pelvic assessments that identify characteristic features of the presenting part. Leopold's maneuvers, a standardized series of four abdominal palpations, are the primary method for determining fetal lie, presentation, position, and degree of engagement in the third trimester and during labor. The first maneuver involves palpating the uterine fundus with both hands to identify the pole at the top: a hard, round, movable mass indicates the fetal head (suggesting cephalic presentation in a longitudinal lie), while a softer, irregular mass suggests the breech.^[3] The second maneuver assesses the fetal back and small parts by running the palms down the sides of the abdomen; a smooth, resistant surface denotes the back on that side, with irregular nodules indicating limbs, helping to confirm the position (e.g., left or right occiput anterior).^[3] In the third maneuver, the examiner grasps the presenting part just above the symphysis pubis with the thumb and middle finger to evaluate engagement: a cephalic presentation feels firm and ballotable if not fully engaged, while deeper descent suggests advancement into the pelvis.^[3] The fourth maneuver, performed with the patient in a slight dorsal position, uses both hands to outline the cephalic contour laterally; this determines flexion attitude, with a well-flexed vertex presenting as a compact mass.^[3] These steps collectively differentiate cephalic from non-cephalic presentations and refine positional details essential for labor planning. Vaginal examination complements abdominal palpation, particularly during the active phase of labor, by directly assessing the presenting part after membrane rupture or in the second stage. For vertex presentation within cephalic, the examiner identifies sagittal and coronal sutures intersecting at the fontanelles: the anterior fontanelle (bregma) feels like a diamond-shaped area, and the posterior fontanelle (lambda) like a triangular notch, confirming the occiput's position relative to the maternal pelvis. In brow or face presentations, also cephalic variants, digital palpation reveals distinct features: the brow shows supraorbital ridges, while the face displays the nose, mouth, malar bones, or chin, allowing differentiation from vertex.^[2] This examination evaluates cervical dilation, effacement, and station simultaneously, providing immediate confirmation of presentation type.^[2] Auscultation of the fetal heart rate (FHR) aids in inferring fetal position by locating the point of maximum intensity, typically over the fetal back or upper chest. In cephalic presentation, the FHR is often heard loudest low in the abdomen, near or below the umbilicus for occiput anterior positions, shifting higher for posterior or lateral orientations; this correlates with Leopold's findings to map the lie.^[52] Intermittent auscultation every 15-30 minutes in low-risk labor uses a fetoscope or Doppler to not only monitor well-being but also support positional diagnosis.^[53] Despite their utility, physical examinations like Leopold's maneuvers are operator-dependent, with accuracy varying based on provider experience and maternal factors. Studies show high sensitivity (93%) and accuracy (89%) for detecting vertex presentation but low specificity (30%), potentially missing malpresentations and leading to over- or underestimation of position.^[54] Challenges arise in cases of maternal obesity, where adipose tissue obscures palpation, or polyhydramnios, which increases uterine fluid and reduces fetal ballotability, diminishing reliability.^[55] These limitations highlight the need for clinical expertise and supplementary confirmation in ambiguous scenarios.

Imaging Techniques

Ultrasonography is the primary imaging modality for confirming and characterizing cephalic presentation, offering high-resolution visualization of the fetal head as the presenting part in late pregnancy and during labor. Transabdominal ultrasound is the standard approach for assessing fetal lie and overall presentation, typically performed in the third trimester to identify whether the head is engaged in the pelvis.^[56] This method allows clinicians to distinguish cephalic from non-cephalic presentations with exceptional reliability, achieving accuracy rates approaching 100% when conducted by experienced operators.^[57] For more detailed evaluation of head position, such as occiput orientation (anterior, posterior, or transverse), transvaginal ultrasound provides enhanced precision, particularly in cases where transabdominal views are obscured by maternal body habitus or fetal position. Key ultrasound views include the sagittal plane, which assesses fetal attitude and head flexion, and the transverse plane, which evaluates rotation and occiput position relative to the maternal midline by identifying the relationship between the fetal skull and spine.^[58] Doppler ultrasonography is routinely incorporated to measure fetal heart rate, confirming viability and cardiac activity during the examination.^[59] Ultrasound screening for presentation is recommended around 36 weeks of gestation to assess version and detect potential malpositions, enabling timely interventions like external cephalic version if indicated. Overall diagnostic accuracy for cephalic presentation exceeds 95%, surpassing physical examination alone and serving as the gold standard for confirmation.^[60]^[61] Magnetic resonance imaging (MRI) plays a limited role in routine cephalic presentation assessment but is occasionally employed in complex cases involving suspected fetal anomalies, such as brain malformations that may complicate delivery or require multidisciplinary planning. It provides superior soft-tissue contrast to ultrasound for detailed anatomical evaluation when anomalies are suspected.^[62]

Management

Routine Labor Management

In uncomplicated cephalic presentation, particularly vertex, routine labor management emphasizes supportive care, vigilant monitoring, and timely interventions to facilitate safe vaginal delivery. The process begins with confirmation of fetal engagement, which typically occurs when the biparietal diameter of the fetal head passes the pelvic inlet, allowing for optimal descent during labor.^[63] Monitoring during labor is essential to assess fetal well-being and labor progress. Continuous electronic fetal heart rate (FHR) monitoring is recommended for high-risk cases, while intermittent auscultation every 15-30 minutes during the first stage and every 5-15 minutes during the second stage suffices for low-risk pregnancies with vertex presentation. Uterine contractions are evaluated for frequency, duration, and intensity, aiming for 3-5 contractions every 10 minutes in active labor; maternal vital signs, including blood pressure and temperature, are checked hourly. The first stage of labor involves cervical dilation and fetal descent, divided into latent (0-6 cm dilation) and active (6-10 cm) phases. In vertex presentation, spontaneous internal rotation to occiput anterior (OA) position usually occurs as the head descends through the pelvis, with effacement and dilation progressing at approximately 1-2 cm per hour in nulliparous women. Supportive measures include hydration, ambulation if possible, and pain relief options such as epidurals, which do not routinely prolong uncomplicated labor.^[21] During the second stage, from full cervical dilation to delivery, pushing is encouraged once the woman feels the urge, typically lasting 1-3 hours in nulliparous women with epidural analgesia. For OA vertex alignment, directed pushing in semi-Fowler or hands-and-knees positions promotes descent and rotation; delayed pushing (up to 1-2 hours) may be used if fetal oxygenation is reassuring.^[64] Augmentation with intravenous oxytocin is indicated if active phase labor prolongs without adequate contractions, following a 4-hour trial of adequate contractions in nulliparous women or 6 hours in multiparous, provided no contraindications like fetal distress exist. Dosing starts at 0.5-2 mU/min, increasing every 30 minutes until adequate contractions (3-5 every 10 minutes) are achieved or the maximum dose is reached, with concurrent FHR monitoring to avoid hyperstimulation.^[64] Delivery in uncomplicated vertex cephalic presentation is preferably spontaneous vaginal, with the fetal head crowning followed by restitution, external rotation, and expulsion of shoulders. Operative vaginal delivery using vacuum extraction or forceps may be employed for maternal exhaustion or prolonged second stage, restricted to outlet or low forceps in OA position to minimize risks. Episiotomy is performed selectively for fetal compromise, shoulder dystocia anticipation, or instrumental delivery, as routine use does not improve outcomes.^[65]

Interventions for Malpositions

Interventions for malpositions in cephalic presentations, such as persistent occiput posterior (OP), brow, or face positions, aim to facilitate vaginal delivery or prevent complications like prolonged labor and fetal distress. Manual rotation is a primary technique for correcting persistent OP position during the second stage of labor, involving gentle digital manipulation of the fetal head from OP to occiput anterior (OA) by an experienced provider. This procedure has a success rate of approximately 80-90%, significantly reducing the need for operative vaginal delivery or cesarean section compared to failed rotations, where cesarean rates can exceed 50%.^[66]^[67] For face presentations, operative vaginal delivery using vacuum or forceps is feasible only if the mentum (chin) is anterior, allowing flexion and descent through the pelvis; posterior mentum positions prevent this due to the inability to extend the neck further. In such cases, successful operative delivery can achieve vaginal birth without excessive traction, though it requires careful monitoring to avoid trauma. Brow presentations, characterized by partial extension of the fetal head, rarely allow vaginal delivery as the presenting diameter is too large for the pelvic inlet, often necessitating conversion attempts or prompt cesarean section if persistence occurs.^[68] Cesarean delivery is indicated for persistent brow presentations, posterior face positions (mentum posterior), or failed manual rotation in OP cases, particularly if accompanied by arrest of descent, fetal intolerance, or maternal exhaustion. These interventions lower perinatal morbidity compared to prolonged attempts at vaginal birth in uncorrectable malpositions. Manual rotation is not recommended for brow or face presentations, as attempts at manipulation can increase risks of maternal injury and neonatal trauma.^[68]^[67] Adjunctive measures include maternal positioning, such as hands-and-knees posture, which may promote spontaneous rotation in OP positions by altering pelvic dimensions and gravitational forces, though evidence from systematic reviews shows limited efficacy in consistently achieving OA at delivery. Epidural analgesia, while beneficial for pain relief, is associated with higher rates of persistent OP and malrotation, potentially prolonging the second stage by 1-2 hours and increasing instrumental delivery needs; thus, its use should be balanced with proactive rotation strategies. All interventions require continuous fetal heart rate monitoring and multidisciplinary involvement to optimize outcomes.^[69]^[70]

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A brow presentation is unstable and tends to convert to a vertex or face presentation. The aetiology is similar to that of face. There is no mechanism for brow ...Missing: progression | Show results with:progression
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Intrapartum three‐dimensional ultrasonographic imaging of face ...
Jan 5, 2012 · In face presentation the head presents with the submentobregmatic diameter, which at around 9.5 cm is as large as that in vertex presentation.
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Face Presentation - D. El-Mowafi
Obstetrics Simplified - Diaa M. EI-Mowafi. Face Presentation. Definition. It is a cephalic presentation in which the head is completely extended. Incidence.
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Diagnosis and management of face presentation: a case report ...
Sep 25, 2025 · Established risk factors for face presentation include fetal anomalies (e.g., anencephaly), multiparity, and polyhydramnios. Additionally, any ...
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Preoperative Predictors of Successful External Cephalic Version ...
Dec 24, 2024 · The success rate of ECV in 207 pregnancies with a breech presentation at term was 68.6%. The rates of failed ECV after four to five attempts ...Missing: sources | Show results with:sources
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Mar 5, 2015 · From 22 to 36 weeks of gestation, the prevalence of cephalic presentation increased from 47% (45–50%) to 94% (91–96%), before and after which ...
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Full article: Changes in fetal presentation in the preterm period and ...
Nov 3, 2022 · This study aimed to clarify the transition of fetal presentation during pregnancy and to propose practical strategy to predict final fetal presentation.<|control11|><|separator|>
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What is the most common type of presentation in a twin gestation at ...
Aug 20, 2025 · The most common type of presentation in a twin gestation at term is cephalic/cephalic, occurring in approximately 40-45% of all twin ...
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Chapter 15: Abnormal Cephalic Presentations - AccessObGyn
Multiple pregnancy. Fetal anomalies, including hydrocephaly and anencephaly. Polyhydramnios: An excessive amount of amniotic fluid allows the fetus freedom of ...Missing: variations prevalence multiparous
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A comparison of risk factors for breech presentation in preterm and ...
Nov 18, 2019 · The incidence of breech presentation at delivery decreased from 23.5% in pregnancy weeks 24–27 to 2.5% in term pregnancies. In gestational weeks ...Missing: global | Show results with:global
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External Cephalic Version - AAFP
Sep 1, 1998 · External cephalic version is a procedure that externally rotates the fetus from a breech presentation to a vertex presentation.
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External Cephalic Version: A Retrospective Chart Review at a ...
A breech presentation occurs when the fetal presenting part is non-cephalic. The prevalence of breech presentation at term is approximately 3%–4%. It is ...Missing: reliable | Show results with:reliable
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A Systematic Review of Intrapartum Fetal Head Compression - NIH
Here we systematically review what is known about fetal head compression and its effects on fetal intracranial pressure, oxygenation, blood flow and cerebral ...
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Effect of different labor forces on fetal skull molding - ScienceDirect
The molding of the fetus head during vaginal delivery facilitates the labor progress, since it adjusts to the birth canal geometry.
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Normal Labor | Obgyn Key
Feb 6, 2017 · The occipital fontanel is the presenting part, and this presentation is referred to as a vertex or occiput presentation. Much less commonly, the ...Fetal Position · Diagnosis Of Fetal... · Occiput Anterior...
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Amniotic Fluid: Physiology and Assessment | GLOWM
Amniotic fluid is the product of complex and dynamic fetal and placental physiologic processes. Disruption of the fine balance may result in overproduction ...
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Evolution of the human birth canal - ScienceDirect.com
In physiological cephalic presentation, the fetus aligns the largest dimension of its head with the largest dimension of each of the three planes, leading to a ...
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The obstetrical dilemma hypothesis: there's life in the old dog yet
This reveals that human childbirth is affected by a complex combination of evolutionary, ecological, and biocultural factors, which variably constrain maternal ...Missing: cephalic | Show results with:cephalic
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Breech presentation: its predictors and consequences. An analysis ...
Dec 10, 2015 · Breech presentation is a marker of pathological pregnancy and is independently associated with an increased risk of gestational complications.
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Intrapartum Fetal Monitoring - AAFP
Aug 1, 2020 · Structured intermittent auscultation detects changes in FHR during contractions but not overall FHR variability (moment-by-moment fluctuations ...
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Accuracy and factors influencing Leopold's manoeuvres ... - PubMed
Our study found Leopold's manoeuvre for foetal presentation determination during the late third trimester of pregnancy has high sensitivity but low specificity.Missing: Limitations physical
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Accuracy of Estimated Fetal Weight by Ultrasound vs. Leopold's ...
EFW estimation error from Leopold's maneuvers may be also attributed to performer inexperience as well as maternal conditions such as fibroids, polyhydramnios, ...
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Ultrasound determination of fetal lie and presentation - ISUOG
Traditionally, your obstetric caregiver using standardized manual palpation techniques, commonly known as Leopold's maneuvers, evaluates the fetal lie.
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Universal late pregnancy ultrasound screening to predict ... - NCBI
Ultrasound establishes fetal presentation with 100% accuracy at the time of the scan (although presentation will sometimes change spontaneously after the scan).
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ISUOG Practice Guidelines: performance of first‐trimester fetal ...
Dec 25, 2012 · Transvaginal ultrasound diagnosis of fetal clubfeet at 13 weeks, menstrual age. J Clin Ultrasound. 1989; 17: 518–520. 10.1002/jcu.1870170711.Missing: occiput presentation
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Non-cephalic presentation in late pregnancy - NIH
A better way to diagnose fetal malpresentation would be to perform an ultrasound examination routinely at 35-36 weeks' gestation on every pregnant woman.
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Comparative Study of Ultrasound with Transvaginal Finger ...
Fetal presentation was determined by finger examination in 93% of cases and by ultrasound in 100% of cases. There was moderate agreement (kappa = 0.783) ...
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1.5T magnetic resonance imaging in evaluating fetal head and ...
MRI, on the other hand, can effectively improve the diagnostic accuracy of fetal brain malformations, overcome the limitations of ultrasonography and provide ...
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Management of Normal Labor - Gynecology and Obstetrics
Position describes the relationship of the presenting part to the maternal pelvis (eg, occiput left anterior for cephalic, sacrum right posterior for breech).
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First and Second Stage Labor Management - ACOG
This guideline provides definitions for labor arrest, along with recommendations for management of dystocia in the first and second stages of labor.
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Management of Spontaneous Vaginal Delivery - Merck Manuals
During the second stage of labor, a vaginal examination is done to determine position and station of the fetal head; the head is usually the presenting part.
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The impact of manual rotation of the occiput posterior position on ...
Feb 14, 2018 · Manual rotation is a simple and effective method with a success rate of almost 90%. ... Le Ray has shown that manual rotation significantly ...
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Manual rotation in occiput posterior or transverse positions - PubMed
Failure of manual rotation was associated with a higher cesarean delivery rate than was success (58.8% compared with 3.8%, P<.001). All women with unsuccessful ...
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Management of Brow, Face, and Compound Malpresentations
Aug 1, 2018 · Face presentation occurs because of hyperextension of the neck and the occiput touching the fetal back. Mentum anterior malpresentations can ...Missing: denominators landmarks
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Hands and knees posture in late pregnancy or labour for fetal ...
Use of hands and knees position for 10 minutes twice daily to correct occipito‐posterior position of the fetus in late pregnancy cannot be recommended as an ...Missing: rate | Show results with:rate
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Is epidural analgesia a risk factor for occiput posterior or transverse ...
Epidural placement when the fetal head is still "high" is associated with an increased rate of occiput posterior and transverse malpositions during labour.