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 Table of Contents  
Year : 2018  |  Volume : 4  |  Issue : 1  |  Page : 17-20

Ultrasound evaluation of cervical length in the second trimester of pregnancy: The impact of cesarean section and ethnicity

Department of Diagnostic Radiology, Taibah University, Faculty of Applied Medical Sciences, Medina, Kingdom of Saudi Arabia

Date of Submission22-Dec-2017
Date of Acceptance20-Jan-2018
Date of Web Publication25-May-2018

Correspondence Address:
Moawia Gameraddin
Department of Diagnostic Radiology, Taibah University, Faculty of Applied Medical Sciences, Al-Madinah, Medina
Kingdom of Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcrsm.jcrsm_69_17

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Background and Objective: The sonographic assessment of cervical length (CL) is an important part of ultrasound evaluation in the second trimester of pregnancy. There are specific maternal characteristics and obstetric history which affect the CL. This study aims to assess the influence of mode of delivery and ethnicity on the CL in women with divergent ethnicity.
Materials and Methods: A prospective cross-sectional study was designed, including 109 pregnant Sudanese women in the second trimester. They were investigated with transvaginal ultrasonography (TVS) using high-frequency 7.5-MHz probe to assess the CL. The participants were categorized according to their ethnicity and regions. The results were analyzed using analysis of variance (ANOVA) and Student's independent t-test in the SPSS program version 16 (IBM Inc.) and P > 0.05 considered to be statistically significant.
Results: The mean TVS CL was 38.2 mm in the second trimester of pregnancy. The CL of northern Sudanese women was significantly longer than women from western, southern and eastern Sudan (P = 0.041). The mean CL of previous cesarean-sectioned women was 37.7 mm which was statistically significantly shorter than those who delivered normally (P = 0.03). The CL was not significantly different in multiparous compared to nulliparous women (37.83 vs. 37.78 mm, P= 0.77). Maternal age and gestational age did not significantly change the CL in second and third trimesters, P= 0.69 and 0.99, respectively.
Conclusions: In the light of this study, cesarean section and ethnicity were considered to be significant factors that affect the CL in the second trimester of pregnancy. We suggest transvaginal sonographic measurement of CL as a part of a routine ultrasound evaluation in the second trimester.

Keywords: Cervical length, cesarean section, diversity, ethnicity, trimester

How to cite this article:
Gameraddin M. Ultrasound evaluation of cervical length in the second trimester of pregnancy: The impact of cesarean section and ethnicity. J Curr Res Sci Med 2018;4:17-20

How to cite this URL:
Gameraddin M. Ultrasound evaluation of cervical length in the second trimester of pregnancy: The impact of cesarean section and ethnicity. J Curr Res Sci Med [serial online] 2018 [cited 2023 May 30];4:17-20. Available from: https://www.jcrsmed.org/text.asp?2018/4/1/17/233205

  Introduction Top

The cervical length (CL) is an important factor for evaluating the risks of pregnancy, specifically, prematurity, which remains a major cause of death, more than chromosomal and morphological abnormalities.[1],[2] Preterm birth is a major cause of perinatal morbidity and mortality.[3] Early measurement of the uterine cervix in pregnancy can avoid these risks. In previous studies, there were several factors affecting the length of the cervix such as biological differences among women, incompetent cervix, and endometritis. In literature, CL changes during pregnancy due to physiological factors.[4],[5],[6] The current study aims to evaluate whether ethnicity and mode of delivery are associated with the length of the uterine cervix. Identification of the influence of these factors is very important since it helps clinicians to assess the cervix which is very necessary to avoid the risk of preterm delivery and other complications. However, to the best of our knowledge, the relationship of ethnicity and mode of delivery with CL was less demonstrated in the literature. In most studies, CL was measured to predict the need for cesarean section; but in this study, we evaluated the impact of cesarean section on the length of the uterine cervix.

Transvaginal ultrasonography (TVS) is the best imaging method to assess CL, and it was used in this study to measure the length. In a previous study, TVS was more accurate than transabdominal scanning (TA) in assessing the CL. Westerway et al. revealed that the TA method underestimated CL by 2.0 mm.[7] In general, there was controversy regarding establishing referent value of CL. In this study, CL was measured in pregnant women who were different in ethnicity and regions of Sudan.

  Materials and Methods Top

This is a descriptive cross-sectional study including 109 pregnant women in the second trimester of pregnancy that had been selected from March 2015 to February 2016. The study was conducted in Khartoum State, Sudan in which people with different ethnicity live. The selection of the sample involved the four regions: North, South, West, and East which were different in ethnicity. Every woman was asked about her tribe to determine the ethnicity that had been classified as Arabic origin, African origin, and mixed (Afro-Arabian). Women with diabetes mellitus, eclampsia, history of preterm delivery, twins, thyroid diseases, and history of fetal congenital anomalies had been excluded from the study. The women attended the department for routine antenatal care and ultrasound examination. Informed consent was obtained from the participants. Every woman underwent TVS scanning. A data collection sheet was designed to include the maternal demographic data and clinical history.

The pregnant women were categorized into four ethnic and regional groups: Northern Arabs, Eastern Arabs, Western Afro-Arabs, and Southern Africans. We classified the ethnicity depending on physical appearance, ancestry, language, society, tribes, culture, or nation.[8],[9] The main Sudanese ethnicity is Sudanese Arabs (approximately 70%), Fur, Beja, and Nuba peoples.[10]

The sonographic procedure

The TVS was performed using ultrasound machine SONOACE-CONVEX ARRAY CA/LOGIQ9 with 7-MHz probes. The women were asked to empty the urinary bladder and sited in the dorsal lithotomy position. The vaginal probe was lubricated with gel and introduced into the vagina. The length and width of the cervix were measured with the probe placed in the anterior fornix of the vagina. The cervical canal was identified as a translucent line connecting the external and internal os. The distance between the external and internal os was taken as CL.

Statistical analysis

The statistical analysis was performed using SPSS version 21 (SPSS Inc., Chicago, Ill, USA). Descriptive statistics was used to describe the percentages and frequencies of the demographic data. Student's independent t-test was used to compare the means of CLs of cesarean section and normal deliveries, and between nulliparous and multiparous women. Analysis of variance (ANOVA) was applied to compare the CLs between and within the ethnic groups.

  Results Top

The mean maternal age was 29.6 years and most of the women were in the age group of 20–35 years (65.1%). The frequency of maternal characteristics is shown in [Table 1] and it was observed that 39.4% were nulliparous, 22.9% were multiparous, and 36.7% were grand multiparous. Women who underwent cesarean section was 27.5% and 33.1% delivered normally, as shown in [Table 2]. The mean CL was 38.2 ± 5.2 mm and was compared with that from previous studies, and it was significantly higher (P = 0.00), as revealed in [Table 3]. The CL was significantly shorter in women who underwent cesarean section than those who delivered normally (P = 0.03), as shown in [Table 4]. Maternal age, parity, and gestational age were not significantly affecting the CL during the second trimester of pregnancy,(P= 0.69, 0.77, and 0.99, respectively) [Table 4]. The relation of ethnicity with CL, demonstrated in [Table 5], revealed a significant difference between the ethnicity groups (P = 0.04). Northern Arab women had the longest CL when compared to the other ethnic groups.
Table 1: The frequency of maternal characteristics and gestational age

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Table 2: Frequency distribution of women according to mode of delivery

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Table 3: The measurement of cervical length of the current study compared to previous studies

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Table 4: Measurement of cervical length in relation with age groups, mode of delivery, parity, and gestational age

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Table 5: Relation of cervical length with diversity of ethnicity in Sudanese women

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  Discussion Top

Studies have been done to correlate the influence of cesarian section on cervical length. There appears to be relationship between CL and obstetric outcome. In previous studies, there were many factors that had been demonstrated to have influenced the CL such as parity, cervical incompetence, preterm pregnancy, and mode of delivery. However, to the best of our knowledge, ethnicity was less demonstrated. The study assessed the CL in the main regions of Sudan that contain different ethnic groups such as Arabs and Afro-Arabs.[11]

In the present study, the mean value of CL was 38.20 mm ± 5.2 mm which is significantly higher than reported in most previous studies. Palma et al.[12] reported that the CL of women of Caucasian origin was 36.9 mm and those of African origin was 35.7 mm which were both lesser than the mean value of the current study. Westerway et al.,[7] Retzke et al.,[13] and To et al.[14] reported mean CLs of 33.6 mm, 32 mm, and 36 mm, respectively. These studies were performed in different regions and different populations, and their measurements were significantly shorter than the mean value of the current study (38.20 mm). In the present study, it was observed that the mean CL was significantly longer in women from Northern Sudan (39.66 mm) than eastern, western, and southern Sudanese women. These groups were different in ethnicity. This suggests that ethnicity is a significant factor affecting the CL.

The current study revealed that the length of the cervix has an impact on the mode of delivery. It was observed that the cervix is statistically significantly longer in women who delivered vaginally more than those with cesarean section (P = 0.02). However, in literature, we found few studies demonstrating the measurement of the uterine cervix in pregnant women who underwent a cesarean section. Most of the studies had assessed the cervix to predict the risk to pregnancy and to determine the need for cesarean section. Miller et al.[15] reported that increased CL in the second trimester was associated with an increased frequency of cesarean deliveries. In this study, we found that the length of the cervix is significantly longer in women who delivered normally more than those who delivered with cesarean section.

The parity is another factor that may influence the CL. In the current study, the CL showed no statistical difference between nulliparous and multiparous pregnant (37.78 vs. 37.83, P= 0.77). This result is in agreement with Shumaila et al. who reported that there was no statistical difference between multiparous and nulliparous women.[16]

In the present study, the maternal age and gestational age did not significantly affect the length of uterine cervix; P= 0.69 and 0.99, respectively. This is consistent with Soraya et al., [17] who assessedthe CL between 18 and 24 weeks of gestation, and found that cervical biometry was not significantly correlated with the gestational age. Similarly, this result agreed with our findings; the mean CL was 37.25 mm in women <20 years and 38.13 mm in women of 20–35 years which were both insignificantly shorter than women >35 years old (38.79 mm). This indicates that increased maternal age may not have increased or decreased the length of the cervix.

Need further studies with large sample size to confirm the initial results of this study.

  Conclusions Top

CL is one of the most important parts of routine obstetric and gynecological evaluation. Maternal ethnicity was associated with CL.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Mathews TJ, Curtin SC, MacDorman MF. Infant mortality statistics from the 1998 period linked birth/infant death data set. Natl Vital Stat Rep 2000;48:1-25.  Back to cited text no. 1
Marlow N, Wolke D, Bracewell MA, Samara M, EPICure Study Group. Neurologic and developmental disability at six years of age after extremely preterm birth. N Engl J Med 2005;352:9-19.  Back to cited text no. 2
Iams JD, Romero R, Culhane JF, Goldenberg RL. Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth. Lancet 2008;371:164-75.  Back to cited text no. 3
Brieger GM, Ning XH, Dawkins RR, Ying KQ, Weng C, Chang AM, et al. Transvaginal sonographic assessment of cervical dynamics during the third trimester of normal pregnancy. Acta Obstet Gynecol Scand 1997;76:118-22.  Back to cited text no. 4
Iams JD, Goldenberg RL, Meis PJ, Mercer BM, Moawad A, Das A, et al. The length of the cervix and the risk of spontaneous premature delivery. National institute of child health and human development maternal fetal medicine unit network. N Engl J Med 1996;334:567-72.  Back to cited text no. 5
Okitsu O, Mimura T, Nakayama T, Aono T. Early prediction of preterm delivery by transvaginal ultrasonography. Ultrasound Obstet Gynecol 1992;2:402-9.  Back to cited text no. 6
Westerway SC, Pedersen LH, Hyett J. Cervical length measurement: Comparison of transabdominal and transvaginal approach. Australas J Ultrasound Med 2015;18:19-26.  Back to cited text no. 7
Demographics of Sudan. Ethnic groups. Available from: https://en.wikipedia.org/wiki/Demographics_of_Sudan. [Last accessed on 2018 Jan 22].  Back to cited text no. 8
People J, Garrick B. Humanity: An Introduction to Cultural Anthropology. 9th ed. Wadsworth: Cengage Learning; 2010. p. 389.  Back to cited text no. 9
Demographics of Sudan; 2012. Available from: https://www.en.wikipedia.org/wiki/Demographics_of_Sudan#Ethnic_groups. [Last accessed on 2017 Oct 15].  Back to cited text no. 10
Babiker HM, Schlebusch CM, Hassan HY, Jakobsson M. Genetic variation and population structure of Sudanese populations as indicated by 15 identifiler sequence-tagged repeat (STR) loci. Investig Genet 2011;2:12.  Back to cited text no. 11
Palma-Dias RS, Fonseca MM, Stein NR, Schmidt AP, Magalhães JA. Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history. Braz J Med Biol Res 2004;37:737-44.  Back to cited text no. 12
Retzke JD, Sonek JD, Lehmann J, Yazdi B, Kagan KO. Comparison of three methods of cervical measurement in the first trimester: Single-line, two-line, and tracing. Prenat Diagn 2013;33:262-8.  Back to cited text no. 13
To MS, Skentou CA, Royston P, Yu CK, Nicolaides KH. Prediction of patient-specific risk of early preterm delivery using maternal history and sonographic measurement of cervical length: A population-based prospective study. Ultrasound Obstet Gynecol 2006;27:362-7.  Back to cited text no. 14
Miller ES, Sakowicz A, Grobman WA. Association between second-trimester cervical length and primary cesarean delivery. Obstet Gynecol 2013;122:863-7.  Back to cited text no. 15
Shumaila SM, Maqbool A, Malik SA. The role of transvaginal ultrasound in cervical length changes. Biomedica 2009;25:175-7.  Back to cited text no. 16
Andrade S, Andrade F, Júnior EA, Pires C, Mattar R, Moron A. Assessment of Length of Maternal Cervix between 18 and 24 weeks of Gestation in a Low-Risk Brazilian Population. Rev Bras Ginecol Obstet 2017;39:647–52.  Back to cited text no. 17


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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