A clinical study on ultrasonographic measurement of cervical length at 18-24 weeks of gestation and pregnancy outcome

Jayati Nath, Bhattacharjee A. K., Talukdar R. K.


Background: Preterm labour and preterm birth is the leading cause of perinatal mortality, whose incidence is approximately 10% of all live births worldwide. This study was undertaken to evaluate the cervical length ultra-sonographically at 18 to 24 weeks of gestation in asymptomatic women and study the pregnancy outcomes and predicting risk of preterm labour and delivery.           

Methods: This hospital based prospective study was conducted by enrolling 1500 antenatal patients with gestations between 18 and 24 weeks, after fulfilling the inclusion and exclusion criteria. Their cervical lengths were measured by USG and they followed through their pregnancy, labour and delivery & all the relevant data were recorded, studied & statistically analysed.         

Results: Out of 1500 patients enrolled, 90 were lost to follow up. Therefore, all the result analyses were done for 1410 patients. Majority of the patients belonged to age group 21- 30 years (830= 58.86%), primigravida ( 47.87%), from urban background (67.17%), belonged to lower socio-economic status (61.70%), at 21 weeks of gestation (28.15%). 960 patients had labour at term (68.08%), 360 (25.54%) had preterm  and 90 (6.38%) had postterm labour. With cervical length <1.5 cm, all 15 patients went into preterm labour (100%), cervical length 1.5-2.0 cm, 75 patients (92.59%) went into preterm labour, 2.1-2.5 cm cervical length 151 patients (66.81%) went into preterm labour, 2.6-3.0 cm 48 patients(13.79% )patients went into preterm labour & in those patients with cervical length >3.0 cm, 71 (9.59%) landed up in preterm labour. When statistically analysed, the association between cervical length and gestational age at which labour started were very significant and results showed ᵡ2=190.01 , df= 1,  P< 0.0001 (very significant ). As the cervical length increases, the median gestational age at which labour started also increases which was found to be significant (r = 0.98, P<0.01).

Conclusions: Shorter cervices lead to shorter gestations and early labour. Thus ultrasonographic measurement of cervical length at 18-24 weeks of gestation is very important, more so in asymptomatic women and can be utilized as a tool for predicting adverse pregnancy outcome especially preterm labour and delivery.


Cervical length, Ultrasonography, Preterm labour, Preterm delivery, Cervical encirclage, Pregnancy outcome

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