- Dynamic External Pelvimetry Test in Third Trimester Pregnant Women: Shifting Positions Affect Pelvic Biomechanics and Create More Room in Obstetric Diameters. [Journal Article]Cureus. 2021 Mar 01; 13(3):e13631.C
- Dystocia in labor is still a clinical challenge. The "contracted pelvis" is the absence of pelvic mobility, which leads to fetal-pelvic disproportion, obstructed labor, and operative delivery. Maternal pelvis biomechanics studies by high technological techniques have shown that maternal shifting positions during pregnancy and labor can create more room in the pelvis for safe delivery. The externa…
Dystocia in labor is still a clinical challenge. The "contracted pelvis" is the absence of pelvic mobility, which leads to fetal-pelvic disproportion, obstructed labor, and operative delivery. Maternal pelvis biomechanics studies by high technological techniques have shown that maternal shifting positions during pregnancy and labor can create more room in the pelvis for safe delivery. The external and internal pelvic diameters are related. The present study aims to evaluate the external obstetric pelvic diameters in shifting positions using a clinical technique suitable for daily practice in every clinical setting: the dynamic external pelvimetry test (DEP test). Seventy pregnant women were recruited, and the obstetric external pelvic diameters were measured, moving the position from kneeling standing to "hands-and-knees" to kneeling squat position. Results showed modification of the pelvic diameters in shifting position: the transverse and longitudinal diameters of Michaelis sacral area, the inter-tuberosities diameter, the bi-trochanters diameter, and the external conjugate widened; the bi-crestal iliac diameter, the bi-spinous iliac diameter, and the base of the Trillat's triangle decreased. The test showed good reproducibility and reliability. Linear correlations were found between diameters and between the range of motion of the diameters. The maternal pelvis is confirmed to modify the diameters changing its tridimensional shape. The pelvic inlet edge's inclination is inferred to be modified, facilitating the fetal descend. The pelvic outlet enlarged the transverse diameter, facilitating birth. The DEP test estimates the pelvic diameters' modification with postural changes, as magnetic resonance (MR) and computational biomechanics studies have demonstrated.
- Pelvic dimension as a predictor of ureteral injury in gynecological cancer surgeries. [Journal Article]Surg Endosc. 2020 09; 34(9):3920-3926.SE
- CONCLUSIONS: This study demonstrated that mid-pelvis dimensions were associated with ureteral injury, but the observed differences were too small. In addition, pelvic inlet dimensions did not appear to relate with ureteral injury. Thus, these pelvimetry measures could not be beneficial in assessing the risk of ureteral injury in gynecological cancer surgeries.
- How reproducible are classical and new CT-pelvimetry measurements? [Journal Article]Diagn Interv Imaging. 2020 Feb; 101(2):79-89.DI
- CONCLUSIONS: New pelvic measurements have excellent reproducibility and are similar to the classical measurements, based on the MPR analysis of CT planes adjusted to the inner bony pelvis.
- Does obstetric protection apply to small-bodied females?: A comparison between small-bodied Jomon foragers and large-bodied Yayoi agriculturalists in the prehistoric Japanese archipelago. [Journal Article]Am J Hum Biol. 2019 05; 31(3):e23236.AJ
- CONCLUSIONS: These results suggest that the obstetrical dimensions in small-bodied Jomon females were maintained for obstetric needs.
- StatPearls: Anatomy, Abdomen and Pelvis, Pelvic Inlet [BOOK]StatPearls. StatPearls Publishing: Treasure Island (FL)BOOK
- The pelvic inlet, or the upper pelvic narrow, is the anatomical limit between the true pelvis below and the false pelvis above. There are tangible, genetic, and hormonal differences between the male and female pelvis related to reproductive function. In obstetrics, the pelvic inlet is the entrance door toward the birth canal. The fetal cephalic extremity needs to position itself and adapt adequat…
The pelvic inlet, or the upper pelvic narrow, is the anatomical limit between the true pelvis below and the false pelvis above. There are tangible, genetic, and hormonal differences between the male and female pelvis related to reproductive function. In obstetrics, the pelvic inlet is the entrance door toward the birth canal. The fetal cephalic extremity needs to position itself and adapt adequately to compare the smaller diameter with the largest diameter of the space delimited by the anatomical line of the maternal pelvic inlet. The shape of the inlet depends on the general shape of the pelvis, according to the traditional classification of Caldwell and Moloy. The dimensions of its anteroposterior, oblique, and transverse diameters vary according to the morphological type of the pelvis. The proportions of the shape of the internal pelvic spaces correspond to the proportion of the sacral area of Michaelis. There is radiological evidence that the intrapelvic space changes with the posture of the subject. The position taken by the subject influences the values of the transversal and anterior-posterior diameters. This evidence is extremely useful to facilitate fetal entry into the true pelvis and to favor the dilating phase of labor. A method of evaluating the diameters of the endopelvic spaces and their adaptability (mobility) would be beneficial for diagnosing the "contracted pelvis" and avoiding the consequences on the health of the mother and the newborn that protracted labor and an operative birth can involve.
- Study on the cephalopelvic relationship with cephalic presentation in nulliparous full-term Chinese pregnant women by MRI with three-dimensional reconstruction. [Journal Article]Arch Gynecol Obstet. 2018 08; 298(2):433-441.AG
- CONCLUSIONS: BMI is a risk factor for CPD, and fetal weight < 3.5 kg is an important diagnostic indicator for natural delivery in Chinese pregnant women.
- The birth canal: correlation between the pubic arch angle, the interspinous diameter, and the obstetrical conjugate: a computed tomography biometric study in reproductive age women. [Journal Article]J Matern Fetal Neonatal Med. 2019 Oct; 32(19):3255-3265.JM
- CONCLUSIONS: We report significant correlation between the three pelvic landmarks with greatest impact on the prediction of a successful vaginal delivery: the PAA which is easily measured sonographically and the ISD and OC which are not measurable by ultrasound. This correlation may serve as a basis for future studies to assess its utility and prognostic value for a safe vaginal delivery.
- Can three-dimensional pelvimetry using low-dose stereoradiography replace low-dose CT pelvimetry? [Clinical Trial]Diagn Interv Imaging. 2018 Sep; 99(9):569-576.DI
- CONCLUSIONS: Pelvic inlet measurements using SRI are reliable. Compared to CT pelvimetry, SRI leads to a significant decrease in fetal and maternal radiation doses. These findings should prompt physicians to use SRI as the first-line approach for pelvimetry.
- Which Foetal-Pelvic Variables Are Useful for Predicting Caesarean Section and Instrumental Assistance? [Journal Article]Med Princ Pract. 2017; 26(4):359-367.MP
- CONCLUSIONS: The antero-posterior inlet was an efficient variable unlike the obstetric conjugate. The obstetric conjugate diameter should no longer be considered a useful variable in estimating the arrest of labour. Antero-posterior inlet diameter was a sagittal variable that should be taken into account. The comparison of sub-pubic angle and bi-parietal and antero-posterior outlet diameters was useful in identifying a risk of requiring instrumental assistance.
- MR pelvimetry: prognosis for successful vaginal delivery in patients with suspected fetopelvic disproportion or breech presentation at term. [Journal Article]Arch Gynecol Obstet. 2017 Feb; 295(2):351-359.AG
- CONCLUSIONS: In our cohort, MR pelvimetry was a useful tool for prepartal assessment of the female pelvis in the selection of TOL candidates. Yet, it does not seem to yield additional predictive value for women with a previous vaginal delivery.
- Pelvimetry by Three-Dimensional Computed Tomography in Non-Pregnant Multiparous Women Who Delivered Vaginally. [Journal Article]Pol J Radiol. 2016; 81:219-27.PJ
- CONCLUSIONS: The findings of this study present the reference values of the main planes of the true pelvis by 3D CT pelvimetry in a relatively large group of multiparous women who passed a trial of labor successfully. Overall, the pelvises had features of female pelvic bony structure although pelvic diameters were somewhat lower in multiparous women with short stature. The 3D pelvimetry with CT applications may be used as an adjunct to clinical and ultrasonographic examinations to rule out cephalopelvic dystocia in selected cases.
- Persistent occiput posterior. [Journal Article]Obstet Gynecol. 2015 Mar; 125(3):695-709.OG
- Persistent occiput posterior (OP) is associated with increased rates of maternal and newborn morbidity. Its diagnosis by physical examination is challenging but is improved with bedside ultrasonography. Occiput posterior discovered in the active phase or early second stage of labor usually resolves spontaneously. When it does not, prophylactic manual rotation may decrease persistent OP and its as…
Persistent occiput posterior (OP) is associated with increased rates of maternal and newborn morbidity. Its diagnosis by physical examination is challenging but is improved with bedside ultrasonography. Occiput posterior discovered in the active phase or early second stage of labor usually resolves spontaneously. When it does not, prophylactic manual rotation may decrease persistent OP and its associated complications. When delivery is indicated for arrest of descent in the setting of persistent OP, a pragmatic approach is suggested. Suspected fetal macrosomia, a biparietal diameter above the pelvic inlet or a maternal pelvis with android features should prompt cesarean delivery. Nonrotational operative vaginal delivery is appropriate when the maternal pelvis has a narrow anterior segment but ample room posteriorly, like with anthropoid features. When all other conditions are met and the fetal head arrests in an OP position in a patient with gynecoid pelvic features and ample room anteriorly, options include cesarean delivery, nonrotational operative vaginal delivery, and rotational procedures, either manual or with the use of rotational forceps. Recent literature suggests that maternal and fetal outcomes with rotational forceps are better than those reported in older series. Although not without significant challenges, a role remains for teaching and practicing selected rotational forceps operations in contemporary obstetrics.
- [Analysis of normal pelvis morphometry of modern Chinese southern Han female and its correlation with age]. [Journal Article]Zhonghua Fu Chan Ke Za Zhi. 2013 Jul; 48(7):481-5.ZF
- CONCLUSIONS: The shape of the pelvic inlet of Chinese southern Han female changed from sagittal elliptic into transverse elliptic form, and the posterior part of pelvic inlet became larger.Sacral concavity was increased and the pelvis became deeper. Mid pelvis and the pelvic outlet was almost unchanged, and showed no correlation with age.
- [Anthropometric analysis of obstetrical pelvis from Neolithic area: obstetrical consequences. Preliminary study]. [Journal Article]Gynecol Obstet Fertil. 2011 Nov; 39(11):614-9.GO
- CONCLUSIONS: Reconstructions based on Neolithic hominin fossils suggest that obstetrical mechanisms were probably common to Neolithic and modern humans: childbirth would probably require social adaptations and risks of perinatal and obstetric complications were undoubtedly high. However, the differences in morphometric analysis could suggest a change of human pelvis and raise the question of the evolution in obstetrical mechanisms in the future.
- Severe shoulder dystocia with a small-for-gestationaI-age infant: a case report. [Case Reports]J Reprod Med. 2011 Mar-Apr; 56(3-4):178-80.JR
- CONCLUSIONS: Geometric analysis reveals that borderline adequate pelvimetry likely played a significant role in severe shoulder dystocia etiology, even with a small-for-gestational-age infant. We alert obstetric providers to the possibility of severe shoulder dystocia in patients with borderline adequate pelves on clinical examination, even when estimated fetal weight makes cephalopelvic disproportion unlikely.
- Magnetic resonance pelvimetry for trial of labour after a previous caesarean section. [Journal Article]Sultan Qaboos Univ Med J. 2010 Aug; 10(2):210-4.SQ
- CONCLUSIONS: An outlet index of 31.89 ± 2.05 and the pelvic diameters, transverse inlet 12.56 ± 0.80cm, sagittal outlet 10.54 ± 1.00 cm, interspinous diameter10.46 ± 0.89cm, and intertuberous diameter (transverse outlet) 10.89 ± 1.02cm are useful cut-off points for vaginal delivery in our population.
- Three-dimensional pelvimetry by computed tomography. [Journal Article]Radiol Med. 2009 Aug; 114(5):827-34.RM
- CONCLUSIONS: Pelvimetry can be obtained with low interobserver variability on 3D volume-rendered CT reconstructions. Thus, CT pelvimetry is suitable to gain exact knowledge of pelvic anatomy to identify relevant parameters for dystocia in retrospective studies.
- High assimilation of the sacrum in a sample of American skeletons: prevalence, pelvic size, and obstetrical and evolutionary implications. [Journal Article]Am J Phys Anthropol. 2009 Apr; 138(4):429-38.AJ
- High assimilation sacrum is fusion of the caudal-most lumbar vertebra to the first sacral vertebra. Previous studies have shown that high assimilation is associated with clinical problems, including obstetrical difficulty. This study used adult American males (n = 1,048) and females (n = 1,038) of the Hamann-Todd and Terry skeletal collections to determine the prevalence of high assimilation and …
High assimilation sacrum is fusion of the caudal-most lumbar vertebra to the first sacral vertebra. Previous studies have shown that high assimilation is associated with clinical problems, including obstetrical difficulty. This study used adult American males (n = 1,048) and females (n = 1,038) of the Hamann-Todd and Terry skeletal collections to determine the prevalence of high assimilation and its effect on pelvic size, and to consider the obstetrical and evolutionary implications of high assimilation. The prevalence of high assimilation in this sample is 6.3%, with males and females not differing significantly from one another in their prevalence. This prevalence is near the median for that reported in 41 other samples. In both males and females, individuals with high assimilation have significantly longer anteroposterior and posterior sagittal diameters of the inlet, and shorter sacrum compared to those with a nonassimilated sacrum. Females with high assimilation have a significantly narrower sacral angulation (i.e., reduced inclination of ventral axis of sacrum), and shorter posterior sagittal diameter of the outlet compared to those with a nonassimilated sacrum. A short posterior sagittal diameter of the outlet is associated with childbirth difficulty. As high assimilation is partial homeotic transformation of a lumbar vertebra, this study supports previous research that homeotic transformation of vertebrae is selectively disadvantageous.
- Racial differences in pelvic anatomy by magnetic resonance imaging. [Journal Article]Obstet Gynecol. 2008 Apr; 111(4):914-20.OG
- CONCLUSIONS: White women have a wider pelvic inlet, wider outlet, and shallower anteroposterior outlet than African-American women. In addition, after vaginal delivery, white women demonstrate less pelvic floor mobility. These differences may contribute to observed racial differences in obstetric outcomes and to the development of pelvic floor disorders.
- Anthropometric measurements in the diagnosis of pelvic size: an analysis of maternal height and shoe size and computed tomography pelvimetric data. [Journal Article]Arch Gynecol Obstet. 2007 Nov; 276(5):523-8.AG
- CONCLUSIONS: Measurements of maternal height, shoe size and weight at the last clinic visit are not useful for the identification of women with inadequate pelvis.
- Costal process of the first sacral vertebra: sexual dimorphism and obstetrical adaptation. [Journal Article]Am J Phys Anthropol. 2007 Mar; 132(3):395-405.AJ
- The human sacrum is sexually dimorphic, with males being larger than females in most dimensions. Previous studies, though, suggest that females may have a longer costal process of the first sacral vertebra (S1) than males. However, these studies neither quantified nor tested statistically the costal process of S1. This study compares S1 with the five lumbar vertebrae (L1 to L5) for a number of me…
The human sacrum is sexually dimorphic, with males being larger than females in most dimensions. Previous studies, though, suggest that females may have a longer costal process of the first sacral vertebra (S1) than males. However, these studies neither quantified nor tested statistically the costal process of S1. This study compares S1 with the five lumbar vertebrae (L1 to L5) for a number of metric dimensions, including costal process length. Four issues are addressed, the: 1) hypothesis that females have a longer costal process of S1 than males; 2)hypothesis that homologous structures (i.e., costal processes of L1 to S1) differ in their direction of sexual dimorphism; 3) importance of the costal process of S1 to the obstetrical capacity of the pelvis; and 4) evolution of sexual dimorphism in costal process length of S1. One hundred ninety-seven individuals, including males and females of American blacks and whites, from the Hamann-Todd and Terry Collections were studied. Results show that males are significantly larger than females for most vertebral measurements, except that females have a significantly longer costal process of S1 than males. Costal process length of S1 is positively correlated with the transverse diameter and circumference of the pelvic inlet. The magnitude of sexual dimorphism in costal process length of S1 ranks this measure among the most highly dimorphic of the pelvis. Compared with the humans in this study, australopithecines have a relatively long costal process of S1, but their broad sacrum was not associated with obstetrical imperatives.
- Vaginal birth after cesarean section: X-ray pelvimetry at term is informative. [Journal Article]J Perinat Med. 2006; 34(3):212-5.JP
- CONCLUSIONS: X-ray pelvimetry tailors the information given to each patient about the likelihood of having a vaginal delivery. It can also be used to optimize the selection of patients allowed to enter labor.
- Dynamic assessment of pelvic floor and bony pelvis morphologic condition with the use of magnetic resonance imaging in a multiethnic, nulliparous, and healthy female population. [Journal Article]Am J Obstet Gynecol. 2004 Jul; 191(1):83-9.AJ
- CONCLUSIONS: Nulliparous, healthy white women have larger levator hiatus and bony pelvis with greater bladder neck descent on straining than non-white women.
- Architectural differences in the bony pelvis of women with and without pelvic floor disorders. [Journal Article]Obstet Gynecol. 2003 Dec; 102(6):1283-90.OG
- CONCLUSIONS: A wide transverse inlet and narrow obstetrical conjugate are associated with pelvic floor disorders. We speculate that these features of bony pelvic architecture may predispose the patient to neuromuscular and connective tissue injuries, leading to the development of pelvic floor disorders.
- Intrapartum assessment of fetal head engagement: comparison between transvaginal digital and transabdominal ultrasound determinations. [Multicenter Study]Ultrasound Obstet Gynecol. 2003 May; 21(5):430-6.UO
- CONCLUSIONS: These data demonstrate a high rate of agreement (85.6%) between ultrasound determination and transvaginal digital assessment of fetal head engagement. Examiner experience had no effect. These data support the use of intrapartum transabdominal assessment of fetal head engagement.
- Intrapartum ultrasonographic depiction of fetal malpositioning and mild parietal bone compression in association with large lower segment uterine leiomyoma. [Case Reports]J Matern Fetal Med. 1999 Jan-Feb; 8(1):28-31.JM
- With normal flexion of the fetal head prior to and during early normal labor, the fetal biparietal diameter becomes engaged in (and subsequently traverses) the anterior posterior aspect of the pelvic inlet. Thus, the biparietal diameter (characterized sonographically by depiction of the falx cerebri, thalami, and cavum septum pellucidum) will be obtainable upon transverse suprapubic placement of …
With normal flexion of the fetal head prior to and during early normal labor, the fetal biparietal diameter becomes engaged in (and subsequently traverses) the anterior posterior aspect of the pelvic inlet. Thus, the biparietal diameter (characterized sonographically by depiction of the falx cerebri, thalami, and cavum septum pellucidum) will be obtainable upon transverse suprapubic placement of the ultrasound transducer during the first stage of labor. Deflexion, or extension, of the fetal head may be demonstrated sonographically at the level of the cervical spine. Recently, during intrapartum ultrasonographic assessment of a nulliparous patient with a known, large, lower-segment, uterine fibroid, exhibiting poor progress of labor, the fetal biparietal diameter was documented upon midsagittal suprapubic placement of the transducer. In addition, mild compression of the distal parietal fetal bone was demonstrated and considered consistent with compression by the leiomyoma. Following abdominal delivery, due to fetal distress and arrest of descent, significant deflexion of the fetal head (not suspected by intrapartum cervical examinations) and mild parietal bone depression, consistent with the ultrasonographic examination, were noted.
- Computed tomography comparison of bony pelvis dimensions between women with and without genital prolapse. [Journal Article]Obstet Gynecol. 1999 Feb; 93(2):229-32.OG
- CONCLUSIONS: Women with advanced vaginal prolapse have larger transverse inlet diameters than do women with normal pelvic support.
- Sonographic assessment of symphyseal joint distention intra partum. [Journal Article]Acta Obstet Gynecol Scand. 1997 Mar; 76(3):227-32.AO
- CONCLUSIONS: The symphyseal distention during labor is minimal regardless of parity and size of the child. No added symphyseal distensibility was found in patients with a history of pelvic pain.
- The anterior dimensions of the pelvis in male and female Nigerians. [Journal Article]Afr J Med Med Sci. 1995 Dec; 24(4):329-35.AJ
- A retrospective study on the anteroposterior X-ray films of the pelvis of 40 male, and 31 female Nigerians was undertaken to verify if there was any significant difference in the values of the transverse diameter of the inlet (TID), bicristal diameter (BCD), bituberal diameter (BTD), and subpubic angle (SA) between the male and the female, between the younger age group (21-45 years) and the older…
A retrospective study on the anteroposterior X-ray films of the pelvis of 40 male, and 31 female Nigerians was undertaken to verify if there was any significant difference in the values of the transverse diameter of the inlet (TID), bicristal diameter (BCD), bituberal diameter (BTD), and subpubic angle (SA) between the male and the female, between the younger age group (21-45 years) and the older age group (46-70 years) in each sex, using the student's t-test. Results showed that TID, BTD and SA each was significantly greater in the female than in the male (P < 0.001). BCD showed no significant difference between the sexes (P > 0.05). SA was significantly greater in the older age group than in the younger age group (P < 0.05) while the other variable showed no significant difference. TID showed significant positive correlation with BCD, and BTD in the female (P < 0.05), and with BCD, BTD, and SA in the male (P < 0.05). The value of SA in female is obtuse but overlaps between acute and obtuse in males. Ninety-three per cent of the female pelvis had subpubic angle above the 111.3 degrees demarking point (DP) but none of the male or female pelvis was marked out by the lower or upper demarking points of BCD, suggesting a relevance of DP of SA in sex discrimination. The mean ratio of TID to BTD was 1.5:1 in the male and 1.2:1 in the female suggesting a gynaecoid tendency in the latter. This study provided data that can be useful for clinical and radiological pelvimetry for use in obstetrical care of Nigerian women, and normal values for Nigerian male and female.
New Search Next
- The prognostic value of magnetic resonance imaging for the management of breech delivery. [Journal Article]Eur J Obstet Gynecol Reprod Biol. 1994 Jun 15; 55(2):97-103.EJ
- In patients with breech presentation secondary cesarean section is often caused by a failure to progress in labor due to a disproportion between fetal breech and maternal pelvis. The aim of the present study was to select such patients for primary cesarean section by prenatal use of magnetic resonance imaging. In 39 patients with breech presentation at term, maternal obstetric conjugate, transver…
In patients with breech presentation secondary cesarean section is often caused by a failure to progress in labor due to a disproportion between fetal breech and maternal pelvis. The aim of the present study was to select such patients for primary cesarean section by prenatal use of magnetic resonance imaging. In 39 patients with breech presentation at term, maternal obstetric conjugate, transversal inlet diameter, sagittal mid-pelvis diameter, and interspinal distance, as well as fetal transversal and sagittal breech diameters, were measured by magnetic resonance imaging 1-7 days before delivery. All obstetricians that were involved in this study were blind to the measured values. For statistical evaluation the Mann-Whitney U-test was used. In 13 of these patients a secondary cesarean section was performed due to failure to progress in labor and in 9 due to other indications (intrauterine asphyxia, etc.). Seventeen women were delivered vaginally. The proportion between maternal pelvic inlet and fetal breech diameters was significantly less favourable in patients with failure to progress in labor (n = 13) than that in patients who were delivered vaginally (n = 17) (0.97 +/- 0.06 vs. 0.86 +/- 0.05, P < 0.001). Furthermore, by comparing the maternal pelvic inlet diameters with the corresponding fetal breech diameters, three groups of patients could be selected: one group (A; n = 8), in which the patients could be delivered only by cesarean section, a second group (B; n = 10), in which delivery by both cesarean section and vaginally was possible, and a third group of patients (C; n = 12), in which vaginal delivery was exclusively successful.(ABSTRACT TRUNCATED AT 250 WORDS)