Is mid-gestational cervical length measurement as sensitive prediction factor of preterm delivery in IVF as in spontaneous singleton pregnancies?

OBJECTIVES

To verify the relation between pregnancy duration and cervical length (CL) at 22-24 wks of spontaneous and IVF singleton gestations and to assess its predictive value for preterm delivery (< 37 wks).

MATERIAL &

METHODS

CL at 22-24 wks was performed according to FMF recommendations in 344 women who conceived spontaneously and in 107 IVF singleton pregnancies. The results of CL in both groups were divided into subgroups: ≤ 29 mm, 30-34 mm; 35-39 mm; 40-44 mm; 45-49 mm and ≥ 50 mm. They were subsequently correlated with mean durations of gestation within subgroups and parameters of accuracy were calculated. Correlation and regression analysis was performed.

RESULTS

The average age of women in both groups was 28.1 y.o. (SD=4.2 years) and 33.4 y.o. (SD=4.1 years), respectively. The mean gestation age at delivery was 38.9 wks (SD=2.1 wks) vs. 37.9 wks (SD=2.3 wks) and the rate of prematurity equaled 7% vs. 15%, respectively. Regardless the method of conception there is a positive correlation between the CL and the duration of gestation. The regression analysis showed that the significant increase in pregnancy duration was correlated with CL ≥ 35 mm (correlation coefficient greater for spontaneous vs. IVF: rxy=0.418 vs rxy=0.341; p<0.001). All CL parameters of accuracy were better for spontaneous in comparison to IVF pregnancies.

CONCLUSIONS

IVF singleton pregnancy carries additional risk factors for preterm delivery. Therefore mid-gestational cervical length is less sensitive predictor than in spontaneous singleton gestations.