Biological and Clinical Sciences Research Journal
ISSN: 2708-2261
DOI:
https://doi.org/10.47264/bcsrj0101043
Biol. Clin. Sci.
Res. J., Volume, 2020: e043
PREDICTIVE ACCURACY OF CERVICAL
LENGTH IN MID TRIMESTER ON TRANSABDOMINAL
ULTRASOUND FOR CESAREAN SECTION
KHALID A1, ANJUM MN1, DARAAZ U1,
HUSSAIN K2, OMER MA3
1Department of
Diagnostic Radiology, The University
of Lahore, Lahore, Pakistan
2Social security hospital Kasur, Pakistan
3Department of Radiology, DHQ
Hospital Sheikupura, Pakistan
Corresponding author email: drkhalid.hussain@yahoo.com
Abstract: The
Cesarean section (CS) delivery is a most frequent surgical technique worldwide.
The CS increasing rate and its related problems have drawn an attention towards
CS related morbidity. As recommended by WHO, C-section
could be carried out only when required medically. In mid-pregnancy cervical
extended length predicts the probability of CS early in the pregnancy. The
objective of the study is to find the predictive accuracy of cervical length
(CL) on transabdominal ultrasound for cesarean section
in mid trimester taking mode of delivery as gold standard. It was a cross
sectional study in which 362 females were enrolled. Females were undergoing transabdominal ultrasonography
for assessment of cervical length. A 2x2 contingency table was generated to
calculate sensitivity, specificity, positive predictive valve (PPV), negative
predictive value (NPV) and diagnostic accuracy of transabdominal
ultrasound taking actual mode of delivery as gold standard. The mean age of the
females was 27.92 + 5.75 years while mean parity and mean CL were
2.22 + 1.30 and 35.83 + 7.96 mm, respectively. Among 30 females who had
cervical length <25 mm, 24 had CS and 6 had spontaneous vaginal delivery (SVD).
Among 332 females who had cervical length >25 mm, 96 had CS and 236 had SVD.
The sensitivity, specificity, PPV, NPV and diagnostic accuracy of transabdominal ultrasound for cesarean section were 20.0%,
97.5%, 80.0%, 71.1% and 71.8%, respectively. Study concluded that cesarean
section takes place among pregnant females when cervical length is ≤25mm
on transabdominal ultrasound during mid trimester.
Keywords: Predictive accuracy, cervical length, mid trimester, transabdominal ultrasound, cesarean section
Introduction
“Once a cesarean, always a cesarean” was rule for the traditional CS (cesarean section) however, currently cesarean section is believed a secure delivery mode related to less perinatal difficulties regardless of elevated health and pecuniary cost (Ehtisham and Hashmi, 2014). The CS delivery is a most frequent surgical technique worldwide for females during childbearing age (Anjum et al., 2020) with 18.5 million estimated cases carried out yearly (Stark et al., 2017). Among both developed and industrialized countries, cesarean section is believed an ideal technique for childbirth (Verma et al., 2020). The CS increasing rate and its related problems have drawn an attention towards CS scars as well as their possible related morbidity (Naji et al., 2012). A CS delivery could be conducted based on mother’s pelvis shape or CS previous history. After cesarean section, vaginal birth trial could be possible. As recommended by WHO, C-section could be carried out only when required medically. Several cesarean deliveries are conducted without any medical cause, on someone request, mostly the mother (Caughey et al., 2014). Generally, the cesarean sections lead to a little rise in the poor outcomes among low-risk pregnancies. Also, they normally require longer time to heal, almost 6 weeks (Caughey et al., 2014), than the vaginal delivery. The enhanced risks comprise breathing difficulties in child and postpartum hemorrhage & amniotic fluid embolism in mother. Traditional guidelines propose that CSs not be utilized prior to pregnancy 39 weeks with no any medical cause. The delivery technique does not affect the sexual function afterward (Yeniel and Petri, 2014). The shortening of cervix is an initial step during processes causing labor and may precede the labor by numerous weeks. During 2nd trimester a reduction in the cervical length (CL) is predictive of impulsive preterm delivery, with an elevated risk among females with untimely and significant cervical shortening. As effacement starts at internal cervical os and grows backwardly, it is mostly identified on ultrasound (US) evaluation before it could be valued upon physical examination (Romero et al., 2016; Valentin, 2013). Females who experienced CS were 27.5 percent while 33.1 percent delivered babies normally those identified for cervical length during 2nd trimester (Gameraddin, 2018). Measurement of cervical length utilizing transvaginal ultrasound is a crucial part of evaluating the chance of preterm birth. It is a helpful technique at mid gestation to forecast the possibility of later preterm delivery in asymptomatic females (Kagan and Sonek, 2015).
However, CL is believed as forecaster regarding mode and timing of the delivery, this is not utilized like a screening instrument in asymptomatic low risk populace (Thangaraj et al., 2018). Transabdominal ultrasound is most frequently utilized to attain images of urogenital, hepatobiliary & pelvic structures. Its usefulness regarding imaging the alimentary GIT (gastrointestinal tract) is not well recognized, principally due to technical problems in getting quality images for these areas. Though, advancements in US technology and growing knowledge with US findings in various gastrointestinal complaints are expanding its applications (Nylund et al., 2017). At vaginal assessment, cervix digital evaluation is biased and is unsurprisingly subject to significant bias (Pomorski et al., 2016). Hence, the cervical length measurement on ultrasound is apparently more appealing alternative to forecast the success of labour induction (Hatfield et al., 2007). In mid-pregnancy cervical extended length predicts the probability of CS early in the pregnancy. Therefore, during mid-pregnancy cervical length can be significant to predict the delivery mode during early pregnancy (Kalu et al., 2012). It was reported the transabdominal ultrasonography sensitivity and specificity as an investigation to identify the cervical length upto 25mm were 10 percent and 94 percent, respectively, to predict CS as delivery mode (Westerway et al., 2015). Current study is carried out to get the evidence regarding accuracy of transabdominal ultrasound for prediction of mode of delivery using cervical length in second trimester and plan the mode of delivery and prepare the patients for particular mode of delivery on the basis of cervical length assessment on transabdominal ultrasound. This would help health care providers to improve their practice and will also add information to already existing literature.
Material and methods
It was a cross sectional study in which 362 females were enrolled. Females were undergoing transabdominal ultrasonography for assessment of cervical length by researcher and findings were recorded. Females were labeled as positive or negative and all females were booked and followed-up in OPD by obstetrician. At time of delivery, mode of delivery was noted as decided by obstetrician. Data was entered and statistically analyzed using SPSS 21.0. Quantitative variables were described as mean and SD. Qualitative variables were described as frequency and percentage. A 2×2 contingency table was generated to calculate sensitivity, specificity, PPV, NPV and diagnostic accuracy of transabdominal ultrasound taking actual mode of delivery as gold standard.
Results
Table-1 describes that among 362 females, 140 (38.7%) were up to 25 years old and most of them 180 (49.6%) were 26-35 years old while only 42 (11.7%) females were more than 35 years old. The mean age of the females was 27.92 ± 5.75 years. Table 1a indicates that among 362 females, 22 (6.1%) had no parity while 194 (53.5%) and 146 (40.4%) females had given birth to 1-2 and 3-5 children, respectively. The mean parity among females was 2.22 + 1.30. Table 2 shows that out of 362 females, only 30 (8.3%) had cervical length <25 mm while major proportion 332 (91.7%) of females had cervical length >25 mm. The mean cervical length was 35.83 + 7.96 mm. Table-3 highlights that among 362 females, 120 (33.1%) experienced cesarean section while for majority 242 (66.9%) the mode of delivery was SVD (spontaneous vaginal delivery). Table-4 exhibits that among 30 females who had cervical length <25 mm, 24 (6.6%) had cesarean section and 6 (1.7%) had SVD. Among 332 females who had cervical length >25 mm, 96 (26.5%) had cesarean section and 236 (65.5%) had SVD. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of transabdominal ultrasound for cesarean section were 20.0%, 97.5%, 80.0%, 71.1% and 71.8%, respectively.
Table
1. Frequency distribution of females according to age
|
Age |
Frequency |
Percentage (%) |
|
Upto 25 years |
140 |
38.7 |
|
26-35 years |
180 |
49.6 |
|
Above 35 years |
42 |
11.7 |
|
Total |
362 |
100.0 |
|
Mean + SD |
27.92 + 5.75 |
|
Table 1a:
Frequency distribution of females according to parity
|
Age |
Frequency |
Percentage (%) |
Average Child |
|
Upto 25 years |
194 |
53.5 |
1-2 |
|
26-35 years |
146 |
40.4 |
3.5 |
|
Above 35 years |
42 |
11.7 |
|
|
Average child |
|
|
|
|
Total |
362 |
100.0 |
|
|
Mean + SD |
|
2.22 + 1.30 |
|
Table 2. Frequency distribution of females
according to measurement of cervical length
|
Cervical Length |
Frequency |
Percentage (%) |
|
<25 mm |
30 |
8.3 |
|
>25 mm |
332 |
91.7 |
|
Total |
362 |
100.0 |
|
Mean + SD |
35.83 + 7.96 |
|
Table 3.
Frequency distribution of females according to mode of delivery
|
Mode of Delivery |
Frequency |
Percentage (%) |
|
C-section |
120 |
33.1 |
|
SVD |
242 |
66.9 |
|
Total |
362 |
100.0 |
Table 4. Predictive accuracy of cervical length in
mid trimester on transabdominal ultrasound for
cesarean section
|
Cervical Length |
Mode of |
Delivery |
Total |
||||
|
C-section |
SVD |
||||||
|
<25mm |
24 (6.6%) True positive |
6 (1.7%) False positive |
30 (8.3%) |
||||
|
>25mm |
96 (26.5%) False negative |
236 (65.2%) True negative |
332 (91.7%) |
||||
|
Total |
120 (33.1%) |
242 (66.9%) |
362 (100.0%) |
||||
|
Sensitivity |
Specificity |
PPV |
NPV |
Diagnostic accuracy |
|||
|
20.0% |
97.5% |
80.0 % |
71.1 % |
71.8% |
|||
Discussion
Current study was undertaken to assess the
predictive accuracy of cervical length in mid trimester on transabdominal
ultrasound for cesarean section at Department of Radiology, University
of Lahore, Raiwind Road, Lahore. To acquire adequate outcomes,
a group of 362 females was included in the
study. Study revealed that most of the females were in their good reproductive age group as 88.3% were up to 35
years old and only 11.7% females were more than 35 years old. The mean age of the females was 27.92 + 5.75 years.
The findings of our study are comparable with a study carried out by Gameraddin and Bashab who reported that major proportion (75.5%) of
females was up to 35 years old 24.5%
females were more than 35 years old (Gameraddin and Bashab, 2018). 10 The findings of another study conducted by Nambiar
and his fellows also demonstrated similar
scenario that mean age of the pregnant females was 27.27±4.87 years (Nambiar et al.,
2017). It was found during study that only 6.1%
females had no parity while more than half
(53.5%) of the females delivered 1-2 children and 40.4% females delivered 3-5 children.
The mean parity was 2.22 + 1.30. Nambiar and fellows reported in their study that majority of
females (77.2%) gave birth to one child while 22.8 females gave birth to more
than one child (Nambiar et al.,
2017). Another recent study conducted by Peng and his colleagues indicated that more than half
(55.4%) of the females 19 nulliparous while 44.6%
were multiparous (Peng et al., 2015). Cervical length is believed as important predictor in pregnant females to
assess the mode and timing of the delivery.
It is believed that when cervical length <25 is mm then there is great chance of cesarean section
delivery. It is significant to mention here that only 8.3% females have
cervical length up to 25 mm while significant major (91.7%) had cervical length
above 25 mm. The mean cervical length was 35.83 + 7.96 mm. The findings of
study undertaken by Hernandez-Andrade and his coworker showed almost similar
results that mean cervical length was 34.6+ 7.55 mm (Hernandez-Andrade et
al., 2012). But the results of a study carried out by Gameraddin and Bashab exhibited
different scenario that mean cervical length was 38.20±5.20 mm (Gameraddin and Bashab, 2018) The findings of another study conducted by Buathum a comrades (2019) also confirmed that mean cervical
length was 39.3+6.4 mm. As far as mode of delivery is concerned,
study highlights that among 33.1% females the mode of delivery w cesarean
section while among majority (66.9%) the mo of delivery was SVD
(spontaneous vaginal delivery). The findings
of a similar study carried out by Rane and his
associates exhibited better scenario than our study results who confirmed that
only 18.9% female experienced cesarean section while mainstream (81.1%) females had vaginal delivery (Rane et al.,
2003). Also the results of another study
performed by Gameraddin and Bashab
are better than our study results who stated
that 27.5% females experience cesarean delivery (Gameraddin and Bashab, 2018). When the cervical length and mode of delivery was
assessed, study indicated that among 30 females who has cervical lengths <25 mm, 24 (true positive)
experienced C-section and only 6 (false positive) had
spontaneous vagina delivery. Likewise,
among 332 females who had cervical length >25 mm, 96 (false negative) had
cesarean section and 236 (true negative) had SVD. The sensitivity specificity,
PPV, NPV and diagnostic accuracy transabdominal
ultrasound for cesarean section we 20.0%, 97.5%, 80.0%, 71.1% and 71.8%,
respectively was reported in a recent study carried out by El Mekka and his collaborators reported that CL <28 mm had sensivity
87.5%, specificity 86.3%, PPV 61.4%, and NPV 96.5% the induction of successful
labor (El Mekkawi et
al., 2019). In a study, Saul and his colleagues found 100
percent sensitivity of transabdominal ultrasonography for cervical length assessment upto 25 mm (Saul et al.,
2008). Westerway and
his colleagues reported that transabdominal ultrasonography
sensitivity a specificity to identify the cervical length up to 25mm was 10
percent and 94 percent, respectively, to predict CS delivery mode (Westerway et al.,
2015).
Conclusion
Study concluded that cesarean section takes place among pregnant females when cervical length is ≤25mm on transabdominal ultrasound during mid trimester.
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