Validation of a Nomogram for Predicting Preterm Birth in Women With Threatened Preterm Labor: A Prospective Cohort Study in Iranian Tertiary Referral Hospitals

Abstract

In this prospective cohort study, we aimed to investigate external validity of the Allouche’s nomogram to predict preterm birth in symptomatic women in Iran. We employed six variables of cervical length, uterine contractions, rupture of membranes, vaginal bleeding, gestational age, and multiple pregnancy to draw the nomograms. These variables were examined in the first day of women’s hospitalization and participants followed up until giving birth. The concordance index of area under the curve (AUC) was used for validation of the nomograms. Of the participants 10% gave birth within 48 hours and 29% before 34 weeks. The nomogram had sufficient accuracy in predicting birth within 48 hours (AUC 0.89 [95% CI 0.82–0.96]) and birth before 34 weeks (AUC 0.89 [95% CI 0.84–0.94]). The optimal risk threshold for nomogram predicting birth within 48 hours was 0.16. Use of these two nomograms, can improve the health of women and their neonates.

Development and validation of a nomogram for predicting preterm birth among pregnant women who had Antenatal care follow-up at University of Gondar Comprehensive Specialized Hospital using maternal and fetal characteristics: Retrospective follow-up study

“…This nomogram performed better than a study from Netherlands with an AUC of 63%, which was developed by combining Previous preterm birth, drug abuse, and vaginal bleeding[55], a study from the USA with a combination of received hydroprogestrone caproate ,cervical length, and cervical funnel with an AUC of 63%[56], and another study from the USA with a performance of 68.8%, developed by combining age of spouse, smoking, infection, previous CS, prepregnancy weight, race, hypertension ,prenatal care, prepregnancy DM, plurality, education, age, previous preterm birth, and gestational hypertension[57] .The difference might be due to a difference in the number of predictors used to develop the models, the selection of the study population (only nulliparous was considered in the model from the USA), and the time point difference (early pregnancy was the time for the last study).However, the discriminative performance of the model was lower than a study done in china by combining maternal age, insulin use, and monocyte count with AUC of 88.5% [58], from Iran by combining cervical length, uterine contractions, rupture of membranes, vaginal bleeding, gestational age, and multiple resulting in AUC of 89.0%[59], from China by combining gestational Age, magnesium, fundal height, serum inorganic phosphorus, mean platelet volume, waist size, total cholesterol, triglycerides, globulins, and total bilirubin yielding AUC of 88.5 [60] …”