Preterm Delivery; Who Is at Risk?

Recurrent preterm delivery following twin versus singleton preterm delivery: A retrospective cohort

OBJECTIVE

The main risk factor for preterm delivery (PTD; <37 gestational weeks) is having a history of PTD. The aim of this research was to compare the risk for recurrent PTD following twin versus singleton gestation PTD.

METHODS

A retrospective population-based cohort study was performed, including all women who had two consecutive pregnancies, the first of which ended with PTD. The incidence of PTD recurrence was compared between women with PTD in twin versus singleton gestation. Multivariable logistic models were used to study the association between twinning status and PTD recurrence, and specifically by gestational age of the first PTD, inter-pregnancy interval (IPI), and mode of conception.

RESULTS

The study population included 15 590 women, of whom 1680 (10.8%) had twins in their index pregnancy and 13 910 (89.2%) had singletons. The incidence of recurrent PTD was 10.5% (n = 177) following twin PTD versus 21.9% (n = 3044) following singleton PTD (adjusted odds ratio = 0.50, 95% confidence interval 0.32-0.76, while controlling for confounding variables). The results were consistent while stratifying by IPI, gestational age of the first PTD, or mode of conception.

CONCLUSIONS

Women with PTD in twin gestations are at lower risk for recurrent PTD compared with women with singleton PTD.

Cervical length screening among low-risk women; relationship of body mass index on cervical length and risk of preterm birth

BACKGROUND

Preterm birth (PTB) contributes to nearly 11% of all deliveries in the world. The majority of spontaneous preterm birth (sPTB) remains unexplained. Risk factors include abnormal body mass index (BMI), short cervical length, comorbidities and many more. However, there is limited study on the association between body mass index, cervical length and preterm birth in Malaysia among low-risk women. Hence, we aim to examine the relationship between body mass index, cervical length and the risk of spontaneous preterm birth.

METHOD

In this prospective cohort study, pregnant women between 16 and 24 weeks who fulfilled the criteria were recruited. Women with history of preterm birth were excluded. Demographic and clinical data (age, BMI, ethnicity, education level and parity) were obtained. Cervical length was measured using transvaginal scan. Patients were then followed up till delivery to determine their delivery gestation and outcome of delivery.

RESULTS

Out of 153 women who participated in this study, 146 women had cervical length of more than 30 mm, six had cervical length between 25 mm and 30 mm and one had cervical length of 24 mm. There were nine (9) cases of sPTB, with all of them being late preterm with normal midtrimester cervical length. Almost half of them (44%) were overweight/obese. A significant association was found between age, cervical length, and parity compared to BMI. Nevertheless, no significant association was seen between the BMI and risk of sPTB.

CONCLUSION

This study demonstrates a higher BMI is associated with longer cervical length, but it is not necessarily protective against sPTB. Hence, we concluded there is a limited role in cervical length screening among low-risk women regardless of their BMI in predicting sPTB.

Utilidad del volumen cervical o longitud cervical en la predicción de parto pretérmino inminente en pacientes sintomáticas

Introducción: el volumen cervical es un indicador del proceso de remodelación del cuello uterino. Investigaciones previas han señalado que puede superar la precisión pronóstica de la longitud cervical en la predicción del parto pretérmino. Objetivo: establecer la utilidad del volumen cervical comparado con la longitud en la predicción de parto pretérmino inminente en pacientes sintomáticas. Materiales y métodos: estudio prospectivo realizado de junio 2014 a mayo 2020 en pacientes con diagnóstico de amenaza de parto pretérmino. A todas se les realizo la cuantificación del volumen y longitud cervical por ecografía transvaginal en la hora siguiente a la admisión. Fueron clasificados en aquellas con partos antes de 7 días (grupo A) y con más de 7 días (grupo B). Resultados: para el análisis final se incluyeron 326 pacientes, 152 (31,7%) pertenecieron al grupo A y 251 al B. Las primeras presentaron valores menores de volumen cervical y longitud cervical comparadas con las del grupo B (p < 0,0001). El volumen mostró un valor de área de 0,897 comparado con 0,977 de la longitud cervical para la predicción de parto pretérmino inminente (p < 0,0001). Conclusión: el volumen cervical es menos útil que la longitud en la predicción de parto pretérmino inminente en pacientes sintomáticas.

Analysis of risk factors related to extremely and very preterm birth: a retrospective study

Background:

Preterm birth is one of the main causes of perinatal morbidity and mortality and imposes a heavy burden on families and society. The aim of this study was to identify risk factors and analyze birth conditions and complications of newborns born at < 32 gestational weeks for extremely preterm (EP) and very preterm (VP) birth in the clinic to further extend the gestational period.

Methods:

We performed a retrospective cohort study and collected data from 1598 pregnant women and 1660 premature newborns (excluding 229 premature babies who died due to severe illness and abandonment) admitted to the Obstetrics and Gynecology Hospital Affiliated with Nanjing Medical University in China from 2016 to 2020. We compared women’s and newborns’ characteristics by t-tests and Chi-square tests for continuous and categorical variables, respectively. Multivariable logistic regression was performed to estimate the effects of risk factors on EP and VP birth.

Results:

We identified 3 independent risk factors for EP birth: cervical incompetency (P < 0.001); multiple pregnancy (P < 0.01), primipara (P < 0.001). Additionally, we identified 4 independent risk factors for VP birth: gestational diabetes mellitus (GDM) (P < 0.05), preterm premature rupture of membrane (PPROM) (P < 0.01), fetal intrauterine distress (P < 0.001), and hypertensive disorder complicating pregnancy (HDCP) (P < 0.001). In addition, pairwise comparisons revealed statistically significant differences in the incidence rates of neonatal pneumonia, bronchopulmonary dysplasia (BPD) and sepsis between the 28–28 + 6 and 29–29 + 6 weeks of gestation groups (P < 0.05). Compared with 28–28 + 6 weeks of gestation, neonatal complications were significantly more common at < 26 weeks of gestation (P < 0.05). The incidence rates of neonatal intracranial hemorrhage(NICH), patent ductus arteriosus(PDA), patent foramen ovale(PFO), pneumonia, BPD and sepsis were significantly higher in the 26–26 + 6 and 27–27 + 6 gestational weeks than in the 28–28 + 6 gestational weeks (P < 0.05).

Conclusion:

PPROM, is the most common risk factor for EP and VP birth, and cervical insufficiency, multiple pregnancy, and primipara are independent risk factors for EP birth. Therefore, during pregnancy, attention should be devoted to the risk factors for PPROM, and reproductive tract infection should be actively prevented to reduce the occurrence of PPROM. Identifying the risk factors for cervical insufficiency, actively intervening before pregnancy, and cervical cervix ligation may be considered to reduce the occurrence of EP labor. For iatrogenic preterm birth, the advantages and disadvantages should be carefully weighed, and the gestational period should be extended beyond 28 weeks to enhance the safety of the mother and child and to improve the outcomes of preterm birth.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05119-7.

Effects of gestational diabetes mellitus and assisted reproductive technology treatment on the risk of preterm singleton birth

Background

Although assisted reproductive technology (ART) plays a critical role in reducing infertility, ART pregnant women are reported at higher risk of preterm birth (PTB). Besides, women undergoing ART encounter a higher risk of developing gestational diabetes mellitus (GDM). However, existing studies on the combined effect of ART treatment and GDM on PTB risk are sparse.

Methods

This population-based retrospective cohort study used nationwide birth certificate data from the US National Vital Statistics System 2015-2019. All mothers who had a singleton live birth without pre-pregnancy diabetes were included. Multivariable logistic regression models were used to estimate the odds ratio (OR) of PTB.

Results

We finally included 18,140,241 American mother-infant pairs. The overall rate of PTB was 7.92% (n = 1,436,328). The PTB rate for non-ART mothers without GDM, ART mothers without GDM, non-ART mothers with GDM, and ART mothers with GDM were 7.67, 10.90, 11.23, and 14.81%, respectively. The incidence of GDM in ART mothers (10.48%) was significantly higher than in non-ART mothers (6.26%). After adjusting for potential confounders, compared with non-ART mothers without GDM, the PTB risk was significantly increased for ART mothers without GDM (AOR: 1.47, 95% CI 1.44-1.50), non-ART mothers with GDM (AOR:1.35, 95% CI 1.34-1.36) and ART mothers with GDM (AOR: 1.82, 95% CI 1.74-1.90) respectively, showing an increasing tendency. This phenomenon was stable among mothers in all groups of mothers older than 25 years.

Conclusion

To prevent PTB, effective approaches for the prevention of GDM are crucial to mothers who conceived through ART.

"Advances in Preterm Delivery"-How Can We Advance Further?

Preterm delivery (PTD: <37 gestational weeks) complicates 5−13% of deliveries worldwide [...]