Sonopelvimetry: An Innovative Method for Early Prediction of Obstructed Labour
Author(s)
Yinon Gilboa1;2*,
Emma Bertucci3,
Carlotta Cani3,
Maya Spira1;2,
Jigal Haas1;2,
Vincenzo Mazza3,
Reuven Achiron1;2
Affiliation(s)
1 Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat Gan, Israel. 3 Prenatal Medicine Unit, Department of Obstetrics and Gynecology, Modena Hospital, Modena and Reggio Emilia University, Modena, Italy.
1 Department of Obstetrics and Gynecology, Sheba Medical Center, Ramat Gan, Israel. 3 Prenatal Medicine Unit, Department of Obstetrics and Gynecology, Modena Hospital, Modena and Reggio Emilia University, Modena, Italy.
ABSTRACT
Aim: To evaluate an innovative sonopelvimetry method for early prediction of obstructed labour. Methods: A prospective study was conducted in two centers.GPS-based sonopelvimetry, laborProTM (Trig Medical Inc., Yoqneam Ilit, Israel) devise, was used prior to labour in nulliparous women at 39 - 42 weeks gestation remote from labor. Maternal pelvic parameters, including inter-iliac transverse diameter, obstetric conjugate and interspinous diameter were evaluated. Fetal parameters included head station, biparietal diameter and occipitofrontal diameter. Data on delivery and outcome were collected from the electronic files. Results: The innovative use of sonopelvimetry was applied to 154 consecutive women, none of the participants complained of discomfort or complications observed. The mean time of examination was 15 + 2 minutes. Mean time of examination to delivery interval was 4.8 days (range 0 - 16 days). Small interspinous diameter and high head station were the best predictors for obstructed labour. Analysis indicated 87% sensitivity and 61% specificity for birth weight fetal head station and ISD combined in predicting obstructed labour with an area under the curve of 0.77. Conclusions: Our results indicate that GPS-based sonopelvimetry combined with fetal estimated weight is a valuable tool in the risk assessment of obstructed labour. Parameters obtained by sonopelvimetry combined with birth weight may be useful.
Aim: To evaluate an innovative sonopelvimetry method for early prediction of obstructed labour. Methods: A prospective study was conducted in two centers.GPS-based sonopelvimetry, laborProTM (Trig Medical Inc., Yoqneam Ilit, Israel) devise, was used prior to labour in nulliparous women at 39 - 42 weeks gestation remote from labor. Maternal pelvic parameters, including inter-iliac transverse diameter, obstetric conjugate and interspinous diameter were evaluated. Fetal parameters included head station, biparietal diameter and occipitofrontal diameter. Data on delivery and outcome were collected from the electronic files. Results: The innovative use of sonopelvimetry was applied to 154 consecutive women, none of the participants complained of discomfort or complications observed. The mean time of examination was 15 + 2 minutes. Mean time of examination to delivery interval was 4.8 days (range 0 - 16 days). Small interspinous diameter and high head station were the best predictors for obstructed labour. Analysis indicated 87% sensitivity and 61% specificity for birth weight fetal head station and ISD combined in predicting obstructed labour with an area under the curve of 0.77. Conclusions: Our results indicate that GPS-based sonopelvimetry combined with fetal estimated weight is a valuable tool in the risk assessment of obstructed labour. Parameters obtained by sonopelvimetry combined with birth weight may be useful.
Cite this paper
Gilboa, Y. , Bertucci, E. , Cani, C. , Spira, M. , Haas, J. , Mazza, V. and Achiron, R. (2014) Sonopelvimetry: An Innovative Method for Early Prediction of Obstructed Labour. Open Journal of Obstetrics and Gynecology, 4, 757-765. doi: 10.4236/ojog.2014.413105.
Gilboa, Y. , Bertucci, E. , Cani, C. , Spira, M. , Haas, J. , Mazza, V. and Achiron, R. (2014) Sonopelvimetry: An Innovative Method for Early Prediction of Obstructed Labour. Open Journal of Obstetrics and Gynecology, 4, 757-765. doi: 10.4236/ojog.2014.413105.
References
[1] Abou Zahr, C. (1998) Prolonged and Obstructed Labour. In: Murray, C.J.L. and Lopez, A.D., Eds., Health Dimensions of Sex and Reproduction: The Global Burden of Sexually Transmitted Diseases, Maternal Conditions, Perinatal Disorders, and Congenital Anomalies, WHO, Geneva. [2] Athaus, J.E., Peterson, S., Driggers, R., Cootauco, A., Bienstock, J.L. and Blakemore, K.J. (2006) Cephalopelvic Disproportion Is Associated with Altered Uterine Contraction Shape in the Active Phase of Labor. American Journal of Obstetrics & Gynecology, 295, 729-742. [3] Neilson, J.P., Lavender, T., Quenby, S. and Wray, S. (2003) Obstructed Labour. British Medical Bulletin, 67, 191-204. http://dx.doi.org/10.1093/bmb/ldg018 [4] Thurnau, G.R., Scates, D.H. and Morgan, M.A. (1991) The Fetal-Pelvic Index: A Method of Identifying Fetal-Pelvic Disproportion in Women Attempting Vaginal Birth after Previous Cesarean Delivery. American Journal of Obstetrics & Gynecology, 165, 353-358. http://dx.doi.org/10.1016/0002-9378(91)90091-5 [5] Neilson, X.J.P., Lavender, T., Quenby, S. and Wray, S. (2003) Obstructed Labour. British Medical Bulletin, 67, 191-204. http://dx.doi.org/10.1093/bmb/ldg018 [6] Mahler, H. (1987) The Safe Motherhood Initiative: A Call to Action. Lancet, 1, 668-670.
http://dx.doi.org/10.1016/S0140-6736(87)90423-5 [7] World Health Organization (1991) Maternal Mortality Ratios and Rates—A Tabulation of Available Information. 3rd Edition, WHO, Geneva. [8] Zhu, B.P., Grigorescu, V., Le, T., Lin, M., Copeland, G., Barone, M. and Turabelidze, G. (2006) Labor Dystocia and Its Association with Interpregnancy Interval. American Journal of Obstetrics & Gynecology, 195, 121-128. http://dx.doi.org/10.1016/j.ajog.2005.12.016 [9] Main, E.L., Bloomfield, L. and Hunt, G. (2004) Development of a Large-Scale Obstetric Quality Improvement Program That Focused on the Nulliparous Patient at Term. American Journal of Obstetrics & Gynecology, 190, 1747-1756; Discussion 1756-1758. [10] Coonrod, D.V., Drachman, D., Hobson, P., et al. (2008) Nulliparous Term Singleton Vertex Cesarean Delivery Rates: Institutional and Individual Level Predictors. American Journal of Obstetrics & Gynecology, 198, 694.e1-694.e11. [11] Chen, G., Uryasev, S. and Young, T.K. (2004) On Prediction of Cesarean Delivery Risk in a Large Private Practice. American Journal of Obstetrics Gynecology, 191, 617-625.
http://dx.doi.org/10.1016/j.ajog.2004.07.004 [12] Yeo, L. and Romero, R. (2009) Sonographic Evaluation in the Second Stage of Labor to Improve the Assessment of Labor Progress and Its Outcome. Ultrasound in Obstetrics Gynecology, 33, 253-258. http://dx.doi.org/10.1002/uog.6336 [13] Speert, H. (1996) Gustav Adolf Michaelis and Michaelis’ Rhomboid. In: Obstetric and Gynecologic Milestones Illustrated, Parthenon Publishing Group, New York, 162-165. [14] Maharaj, D. (2010) Assessing Cephalopelvic Disproportion: Back to the Basics. Obstetrical & Gynecological Survey, 65, 337-395. http://dx.doi.org/10.1097/OGX.0b013e3181ecdf0c [15] Thomas, S.M., Bees, N.R. and Adam, E.J. (1998) Trends in the Use of Pelvimetry Techniques. Clinical Radiology, 53, 293-295. http://dx.doi.org/10.1016/S0009-9260(98)80130-X [16] Laube, D.W., Varner, M.W. and Cruikshank, D.P.A. (1981) Prospective Evaluation of X-Ray Pelvimetry. JAMA, 13, 2187-2188. http://dx.doi.org/10.1001/jama.1981.03320190045026 [17] Fox, L.K., Hierta-Enochian, G.S., Hamlin, J.A. and Katz, V.L. (2004) The Magnetic Resonance Imaging-Based FetalPelvic Index: A Pilot Study in the Community Hospital. American Journal of Obstetrics & Gynecology, 190, 1679-1688. http://dx.doi.org/10.1016/j.ajog.2004.02.044 [18] Zaretsky, M.V., Alexander, J.M., McIntire, D.D., Hatab, M.R., Twickler, D.M. and Leveno, K.J. (2005) Magnetic Resonance Imaging Pelvimetry and the Prediction of Labor Dystocia. Obstetrics & Gynecology, 106, 919-926. http://dx.doi.org/10.1097/01.AOG.0000182575.81843.e7 [19] Nizard, J., Haberman, S., Paltieli, Y., et al. (2009) Determination of Fetal Head Station and Position during Labor: A New Technique That Combines Ultrasound and a Position-Tracking System. American Journal of Obstetrics Gynecology, 200, 404.e1-5. [20] Haberman, S., Paltieli, Y., Gonen, R., Ohel, G., Ville, Y. and Nizard, J. (2011) Association between Ultrasound-Based Assessment of Fetal Head Station and Clinically Assessed Cervical Dilatation. Ultrasound in Obstetrics Gynecology, 37, 709-711. http://dx.doi.org/10.1002/uog.8875 [21] Barron, L.R., Hill, R.O. and Linklettert, A.M. (1964) X-Ray Pelvimetry. Canadian Medical Association Journal, 91, 1209-1212. [22] Huerta-Enochian, G.S., Katz, V.L., Fox, L.K., Hamlin, J.A. and Kollath, J.P. (2006) Magnetic Resonance-Based Serial Pelvimetry: Do Maternal Pelvic Dimensions Change during Pregnancy? American Journal of Obstetrics Gynecology, 194, 1689-1695. http://dx.doi.org/10.1016/j.ajog.2006.03.008 [23] Kennelly, M.M., Anjum, R., Lyons, S. and Burke, G.J. (2003) Postpartum Fetal Head Circumference and Its Influence on Labour Duration in Nullipara. Journal of Obstetrics & Gynaecology, 23, 496-499. http://dx.doi.org/10.1080/0144361031000153701 [24] Ferguson 2nd, J.E., Newberry, Y.G., De Angelis, G.A., Finnerty, J.J., Agarwal, S. and Turkheimer, E. (1998) The Fetal-Pelvic Index Has Minimal Utility in Predicting Fetal-Pelvic Disproportion. American Journal of Obstetrics Gynecology, 179, 1186-1192. http://dx.doi.org/10.1016/S0002-9378(98)70129-2 [25] Peaceman, A.M., Gersnoviez, R., Landon, M.B., Spong, C.Y., Leveno, K.J., Varner, M.W., Rouse, D.J., Moawad, A.H., Caritis, S.N., Harper, M., Wapner, R.J., Sorokin, Y., Miodovnik, M., Carpenter, M., O’Sullivan, M.J., Sibai, B.M., Langer, O., Thorp, J.M., Ramin, S.M. and Mercer, B.M. (2006) The MFMU Cesarean Registry: Impact of Fetal Size on Trial of Labor Success for Patients with Previous Cesarean for Dystocia. American Journal of Obstetrics Gynecology, 195, 1127-1131.
http://dx.doi.org/10.1016/j.ajog.2006.06.003 [26] Chen, G., Uryasev, S. and Young, T.K. (2004) On Prediction of the Cesarean Delivery Risk in a Large Private Practice. American Journal of Obstetrics & Gynecology, 191, 617-625.
http://dx.doi.org/10.1016/j.ajog.2004.07.004 [27] Roshanfekr, D., Blakemore, K.J., Lee, J., Hueppchen, N.A. and Witter, F.R. (1999) Station at Onset of Active Labor in Nulliparous Patients and Risk of Cesarean Delivery. Obstetrics Gynecology, 93, 329-331. http://dx.doi.org/10.1016/S0029-7844(98)00451-7 [28] Falzone, S., Chauhan, S.P., Mobley, J.A., Berg, T.G., Sherline, D.M. and Devoe, L.D. (1998) Unengaged Vertex in Nulliparous Women in Active Labor. A Risk Factor for Cesarean Delivery. The Journal of Reproductive Medicine, 43, 676-680. [29] Debby, A., Rotmensch, S., Girtler, O., Sadan, O., Golan, A. and Glezerman, M. (2003) Clinical Significance of the Floating Fetal Head in Nulliparous Women in Labor. The Journal of Reproductive Medicine, 48, 37-40. [30] Dupuis, O., Silveira, R., Zentner, A., et al. (2005) Birth Simulator: Reliability of Transvaginal Assessment of Fetal Head Station as Defined by the American College of Obstetricians and Gynecologists Classification. American Journal of Obstetrics Gynecology, 192, 868-874.
http://dx.doi.org/10.1016/j.ajog.2004.09.028 [31] Carollo, T.C., Reuter, J.M., Galan, H.L. and Jones, R.O. (2004) Defining Fetal Station. American Journal of Obstetrics Gynecology, 191, 1793-1796. http://dx.doi.org/10.1016/j.ajog.2004.07.069 [32] Dietz, H.P. and Lanzarone, V. (2005) Measuring Engagement of the Fetal Head: Validity and Reproducibility of a New Ultrasound Technique. Ultrasound in Obstetrics Gynecology, 25, 165-168. http://dx.doi.org/10.1002/uog.1765 [33] Henrich, W., Dudenhausen, J., Fuchs, I., Kamena, A. and Tutschek, B. (2006) Intrapartum Translabial Ultrasound (ITU): Sonographic Landmarks and Correlation with Successful Vacuum Extraction. Ultrasound in Obstetrics Gynecology, 28, 753-760. http://dx.doi.org/10.1002/uog.3848 [34] Eggebo, T.M., Heien, C., Okland, I., Gjessing, L.K., Romundstad, P. and Salvesen, K.A. (2008) Ultrasound Assessment of Fetal Head-Perineum Distance before Induction of Labor. Ultrasound in Obstetrics Gynecology, 32, 199-204. http://dx.doi.org/10.1002/uog.5360 [35] Kalache, K.D., Duckelmann, A.M., Michaelis, S.A., Lange, J., Cichon, G. and Dudenhausen, J.W. (2009) Transperineal Ultrasound Imaging in Prolonged Second Stage of Labor with Occipitoanterior Presenting Fetuses: How Well Does the “Angle of Progression” Predict the Mode of Delivery? Ultrasound in Obstetrics Gynecology, 33, 326-330. http://dx.doi.org/10.1002/uog.6294 [36] Levy, R., Zaks, S., Ben-Arie, A., Perlman, S., Hagay, Z. and Vaisbuch, E. (2012) Can Angle of Progression in Pregnant Women before Onset of Labor Predict Mode of Delivery? Ultrasound in Obstetrics Gynecology, 40, 332-337. http://dx.doi.org/10.1002/uog.11195 [37] Keller, T.M., Rake, A., Michel, S.C., et al. (2003) Obstetric MR Pelvimetry: Reference Values and Evaluation of Interand Intraobserver Error and Intraindividual Variability. Radiology, 227, 37-43. http://dx.doi.org/10.1148/radiol.2271011658 [38] Sporri, S., Theony, H.C., Raio, L., Lachat, R., Vock, P. and Shneider, H. (2002) MR Imaging Pelvimetry: A Useful Adjunct in the Treatment of Women at Risk for Dystocia? AJR, 179, 137-143.
http://dx.doi.org/10.2214/ajr.179.1.1790137
[1] Abou Zahr, C. (1998) Prolonged and Obstructed Labour. In: Murray, C.J.L. and Lopez, A.D., Eds., Health Dimensions of Sex and Reproduction: The Global Burden of Sexually Transmitted Diseases, Maternal Conditions, Perinatal Disorders, and Congenital Anomalies, WHO, Geneva. [2] Athaus, J.E., Peterson, S., Driggers, R., Cootauco, A., Bienstock, J.L. and Blakemore, K.J. (2006) Cephalopelvic Disproportion Is Associated with Altered Uterine Contraction Shape in the Active Phase of Labor. American Journal of Obstetrics & Gynecology, 295, 729-742. [3] Neilson, J.P., Lavender, T., Quenby, S. and Wray, S. (2003) Obstructed Labour. British Medical Bulletin, 67, 191-204. http://dx.doi.org/10.1093/bmb/ldg018 [4] Thurnau, G.R., Scates, D.H. and Morgan, M.A. (1991) The Fetal-Pelvic Index: A Method of Identifying Fetal-Pelvic Disproportion in Women Attempting Vaginal Birth after Previous Cesarean Delivery. American Journal of Obstetrics & Gynecology, 165, 353-358. http://dx.doi.org/10.1016/0002-9378(91)90091-5 [5] Neilson, X.J.P., Lavender, T., Quenby, S. and Wray, S. (2003) Obstructed Labour. British Medical Bulletin, 67, 191-204. http://dx.doi.org/10.1093/bmb/ldg018 [6] Mahler, H. (1987) The Safe Motherhood Initiative: A Call to Action. Lancet, 1, 668-670.
http://dx.doi.org/10.1016/S0140-6736(87)90423-5 [7] World Health Organization (1991) Maternal Mortality Ratios and Rates—A Tabulation of Available Information. 3rd Edition, WHO, Geneva. [8] Zhu, B.P., Grigorescu, V., Le, T., Lin, M., Copeland, G., Barone, M. and Turabelidze, G. (2006) Labor Dystocia and Its Association with Interpregnancy Interval. American Journal of Obstetrics & Gynecology, 195, 121-128. http://dx.doi.org/10.1016/j.ajog.2005.12.016 [9] Main, E.L., Bloomfield, L. and Hunt, G. (2004) Development of a Large-Scale Obstetric Quality Improvement Program That Focused on the Nulliparous Patient at Term. American Journal of Obstetrics & Gynecology, 190, 1747-1756; Discussion 1756-1758. [10] Coonrod, D.V., Drachman, D., Hobson, P., et al. (2008) Nulliparous Term Singleton Vertex Cesarean Delivery Rates: Institutional and Individual Level Predictors. American Journal of Obstetrics & Gynecology, 198, 694.e1-694.e11. [11] Chen, G., Uryasev, S. and Young, T.K. (2004) On Prediction of Cesarean Delivery Risk in a Large Private Practice. American Journal of Obstetrics Gynecology, 191, 617-625.
http://dx.doi.org/10.1016/j.ajog.2004.07.004 [12] Yeo, L. and Romero, R. (2009) Sonographic Evaluation in the Second Stage of Labor to Improve the Assessment of Labor Progress and Its Outcome. Ultrasound in Obstetrics Gynecology, 33, 253-258. http://dx.doi.org/10.1002/uog.6336 [13] Speert, H. (1996) Gustav Adolf Michaelis and Michaelis’ Rhomboid. In: Obstetric and Gynecologic Milestones Illustrated, Parthenon Publishing Group, New York, 162-165. [14] Maharaj, D. (2010) Assessing Cephalopelvic Disproportion: Back to the Basics. Obstetrical & Gynecological Survey, 65, 337-395. http://dx.doi.org/10.1097/OGX.0b013e3181ecdf0c [15] Thomas, S.M., Bees, N.R. and Adam, E.J. (1998) Trends in the Use of Pelvimetry Techniques. Clinical Radiology, 53, 293-295. http://dx.doi.org/10.1016/S0009-9260(98)80130-X [16] Laube, D.W., Varner, M.W. and Cruikshank, D.P.A. (1981) Prospective Evaluation of X-Ray Pelvimetry. JAMA, 13, 2187-2188. http://dx.doi.org/10.1001/jama.1981.03320190045026 [17] Fox, L.K., Hierta-Enochian, G.S., Hamlin, J.A. and Katz, V.L. (2004) The Magnetic Resonance Imaging-Based FetalPelvic Index: A Pilot Study in the Community Hospital. American Journal of Obstetrics & Gynecology, 190, 1679-1688. http://dx.doi.org/10.1016/j.ajog.2004.02.044 [18] Zaretsky, M.V., Alexander, J.M., McIntire, D.D., Hatab, M.R., Twickler, D.M. and Leveno, K.J. (2005) Magnetic Resonance Imaging Pelvimetry and the Prediction of Labor Dystocia. Obstetrics & Gynecology, 106, 919-926. http://dx.doi.org/10.1097/01.AOG.0000182575.81843.e7 [19] Nizard, J., Haberman, S., Paltieli, Y., et al. (2009) Determination of Fetal Head Station and Position during Labor: A New Technique That Combines Ultrasound and a Position-Tracking System. American Journal of Obstetrics Gynecology, 200, 404.e1-5. [20] Haberman, S., Paltieli, Y., Gonen, R., Ohel, G., Ville, Y. and Nizard, J. (2011) Association between Ultrasound-Based Assessment of Fetal Head Station and Clinically Assessed Cervical Dilatation. Ultrasound in Obstetrics Gynecology, 37, 709-711. http://dx.doi.org/10.1002/uog.8875 [21] Barron, L.R., Hill, R.O. and Linklettert, A.M. (1964) X-Ray Pelvimetry. Canadian Medical Association Journal, 91, 1209-1212. [22] Huerta-Enochian, G.S., Katz, V.L., Fox, L.K., Hamlin, J.A. and Kollath, J.P. (2006) Magnetic Resonance-Based Serial Pelvimetry: Do Maternal Pelvic Dimensions Change during Pregnancy? American Journal of Obstetrics Gynecology, 194, 1689-1695. http://dx.doi.org/10.1016/j.ajog.2006.03.008 [23] Kennelly, M.M., Anjum, R., Lyons, S. and Burke, G.J. (2003) Postpartum Fetal Head Circumference and Its Influence on Labour Duration in Nullipara. Journal of Obstetrics & Gynaecology, 23, 496-499. http://dx.doi.org/10.1080/0144361031000153701 [24] Ferguson 2nd, J.E., Newberry, Y.G., De Angelis, G.A., Finnerty, J.J., Agarwal, S. and Turkheimer, E. (1998) The Fetal-Pelvic Index Has Minimal Utility in Predicting Fetal-Pelvic Disproportion. American Journal of Obstetrics Gynecology, 179, 1186-1192. http://dx.doi.org/10.1016/S0002-9378(98)70129-2 [25] Peaceman, A.M., Gersnoviez, R., Landon, M.B., Spong, C.Y., Leveno, K.J., Varner, M.W., Rouse, D.J., Moawad, A.H., Caritis, S.N., Harper, M., Wapner, R.J., Sorokin, Y., Miodovnik, M., Carpenter, M., O’Sullivan, M.J., Sibai, B.M., Langer, O., Thorp, J.M., Ramin, S.M. and Mercer, B.M. (2006) The MFMU Cesarean Registry: Impact of Fetal Size on Trial of Labor Success for Patients with Previous Cesarean for Dystocia. American Journal of Obstetrics Gynecology, 195, 1127-1131.
http://dx.doi.org/10.1016/j.ajog.2006.06.003 [26] Chen, G., Uryasev, S. and Young, T.K. (2004) On Prediction of the Cesarean Delivery Risk in a Large Private Practice. American Journal of Obstetrics & Gynecology, 191, 617-625.
http://dx.doi.org/10.1016/j.ajog.2004.07.004 [27] Roshanfekr, D., Blakemore, K.J., Lee, J., Hueppchen, N.A. and Witter, F.R. (1999) Station at Onset of Active Labor in Nulliparous Patients and Risk of Cesarean Delivery. Obstetrics Gynecology, 93, 329-331. http://dx.doi.org/10.1016/S0029-7844(98)00451-7 [28] Falzone, S., Chauhan, S.P., Mobley, J.A., Berg, T.G., Sherline, D.M. and Devoe, L.D. (1998) Unengaged Vertex in Nulliparous Women in Active Labor. A Risk Factor for Cesarean Delivery. The Journal of Reproductive Medicine, 43, 676-680. [29] Debby, A., Rotmensch, S., Girtler, O., Sadan, O., Golan, A. and Glezerman, M. (2003) Clinical Significance of the Floating Fetal Head in Nulliparous Women in Labor. The Journal of Reproductive Medicine, 48, 37-40. [30] Dupuis, O., Silveira, R., Zentner, A., et al. (2005) Birth Simulator: Reliability of Transvaginal Assessment of Fetal Head Station as Defined by the American College of Obstetricians and Gynecologists Classification. American Journal of Obstetrics Gynecology, 192, 868-874.
http://dx.doi.org/10.1016/j.ajog.2004.09.028 [31] Carollo, T.C., Reuter, J.M., Galan, H.L. and Jones, R.O. (2004) Defining Fetal Station. American Journal of Obstetrics Gynecology, 191, 1793-1796. http://dx.doi.org/10.1016/j.ajog.2004.07.069 [32] Dietz, H.P. and Lanzarone, V. (2005) Measuring Engagement of the Fetal Head: Validity and Reproducibility of a New Ultrasound Technique. Ultrasound in Obstetrics Gynecology, 25, 165-168. http://dx.doi.org/10.1002/uog.1765 [33] Henrich, W., Dudenhausen, J., Fuchs, I., Kamena, A. and Tutschek, B. (2006) Intrapartum Translabial Ultrasound (ITU): Sonographic Landmarks and Correlation with Successful Vacuum Extraction. Ultrasound in Obstetrics Gynecology, 28, 753-760. http://dx.doi.org/10.1002/uog.3848 [34] Eggebo, T.M., Heien, C., Okland, I., Gjessing, L.K., Romundstad, P. and Salvesen, K.A. (2008) Ultrasound Assessment of Fetal Head-Perineum Distance before Induction of Labor. Ultrasound in Obstetrics Gynecology, 32, 199-204. http://dx.doi.org/10.1002/uog.5360 [35] Kalache, K.D., Duckelmann, A.M., Michaelis, S.A., Lange, J., Cichon, G. and Dudenhausen, J.W. (2009) Transperineal Ultrasound Imaging in Prolonged Second Stage of Labor with Occipitoanterior Presenting Fetuses: How Well Does the “Angle of Progression” Predict the Mode of Delivery? Ultrasound in Obstetrics Gynecology, 33, 326-330. http://dx.doi.org/10.1002/uog.6294 [36] Levy, R., Zaks, S., Ben-Arie, A., Perlman, S., Hagay, Z. and Vaisbuch, E. (2012) Can Angle of Progression in Pregnant Women before Onset of Labor Predict Mode of Delivery? Ultrasound in Obstetrics Gynecology, 40, 332-337. http://dx.doi.org/10.1002/uog.11195 [37] Keller, T.M., Rake, A., Michel, S.C., et al. (2003) Obstetric MR Pelvimetry: Reference Values and Evaluation of Interand Intraobserver Error and Intraindividual Variability. Radiology, 227, 37-43. http://dx.doi.org/10.1148/radiol.2271011658 [38] Sporri, S., Theony, H.C., Raio, L., Lachat, R., Vock, P. and Shneider, H. (2002) MR Imaging Pelvimetry: A Useful Adjunct in the Treatment of Women at Risk for Dystocia? AJR, 179, 137-143.
http://dx.doi.org/10.2214/ajr.179.1.1790137