National Institute of Child Health and Human Development
Maternal Fetal Medicine Units Network

MFMU Network A Prospective Study of Screening for Risk
Factors for Spontaneous Preterm Delivery

Related Publications & Presentations:
Singleton Pregnancy
Twin Pregnancy

Objective

To evaluate individually and in combination the screening tests currently advocated to predict spontaneous PROM or preterm labor resulting in a preterm delivery so as to determine their effectiveness in defining women at risk for spontaneous preterm delivery in both singletons and twins.

Conclusion

Fetal fibronectin, cervical length, upper genital tract infection, bacterial vaginosis and previous spontaneous preterm birth were predictors of preterm birth. These factors, when in various combinations, proved to be stronger predictors, depending on race and gestational age. For twins, most known risk factors for spontaneous preterm birth (SPB) were not significantly associated with SPB. At 24 weeks, cervical length ≤ 25 mm was the best predictor of SPB < 32 weeks, < 35 weeks and < 37 weeks. Of the risk factors evaluated at 28 and 30 weeks, FFN was the only significant predictor of SPB < 32 weeks.

Clinical Centers

Magee Womens, Tennessee, Alabama, Wayne State, Cincinnati, Oklahoma, South Carolina, Bowman Gray, Chicago, Ohio State

Major Eligibility Criteria

• Registering for prenatal care prior to 24 weeks gestation
• Informed consent

Stratification

• Singleton pregnancy
• Twin pregnancy

Sample Size

• Singletons Goal = 3,000
• Twins Goal = 150

Scheduled Evaluations/Data Collection

• Visits 1 & 3 (24/28 weeks)
• Questionnaire: demographic data, substance and medication use, previous and current pregnancy history, anthropometrics
• Cervical exam: length, dilation, station, position, consistency, membranes
• Ultrasound for cervical parameters: same as above
• Specimen collection: fetal fibronectin, gram stain for bacterial vaginosis, wet mount for trichomonas, vaginal vaginosis, wet mount for trichomonas, vaginal pH, KOH for yeast
• Serum collection: proteins
• Visits 2 & 4 (26/30 weeks)
• Fetal fibronectin
• Psychosocial questionnaire
• KOH for yeast
• Labor & Delivery:
• Maternal and neonatal outcome

Outcome Measures

• Primary:
• Delivery following spontaneous preterm labor/PROM from 23-34 weeks
• Secondary:
• Delivery following spontaneous preterm labor/PROM from 23-27, 28-34, 35-36 weeks
• Preterm delivery as result of maternal or fetal indications
• Fetal growth retardation
• Infant morbidity
• Gestational age at PROM/delivery

Timetable

• Recruitment
• Singleton (n=3073): 10/92-03/94
• Twin (n=151): 10/92-10/94
• Data collection
• Singleton: 10/92-11/94
• Twin: 06/95-02/96