BBB Research: Consecutive Pregnancies Study

Pregnancy complications and adverse pregnancy outcomes often recur in subsequent pregnancies. In addition to recurrence of the same complication, an adverse outcome in one pregnancy also seems to increase risk for other adverse outcomes in subsequent pregnancies. However, data are limited to assess why some women have a recurrence of complications and adverse outcomes while others do not, and whether risk factors for recurrence are modifiable. Of great interest is whether we can predict when a complication would recur. Clinically, the best information available is prior pregnancy history; however, statistical methods for prediction and risk assessment are lacking. The Consecutive Pregnancies Study was a unique collaborative effort between the Biostatistics & Bioinformatics and the Epidemiology Branches designed to: (1) estimate the association between the occurrence and timing of pregnancy complications among consecutive pregnancies in women; (2) examine the demographic and environmental factors which may influence these associations; and (3) further develop statistical methodology to study associations among multiple pregnancy outcomes. Repeat pregnancy data was collected on 114,679 pregnancies from 51,086 women, delivering ≥20 weeks of gestation from 20 hospitals in the state of Utah from 2002 to 2010.

Using this novel dataset, we investigated how prior pregnancy history data can serve as indicators for subsequent pregnancy complications and neonatal outcomes. Prior to this endeavor, attention for recurrent preterm delivery primarily focused on spontaneous subtypes, but less was known about recurrent indicated preterm delivery. In our first paper, we confirmed prior reports of elevated recurrence rates for prior spontaneous preterm delivery (32%) and provided key evidence that recurrence rates were also high for indicated delivery (23%).

Our team has also conducted work to understand clinical factors related to the increased risk of placenta previa associated with history of prior cesarean. We found that first pregnancy pre-labor cesarean delivery was associated with more than a twofold increased risk of placenta previa in a woman's second pregnancy. This study provides novel evidence that the timing of cesarean delivery relative to labor onset is important, especially given the high percentages of primary and repeat cesarean delivery that occur in the United States.

Collectively these findings have clinical implications for counseling and managing patients and for preventing adverse outcomes in subsequent pregnancies using information from prior pregnancies as a guide. For example, women with a prior uncomplicated pregnancy can be counseled on modifying risky behaviors for preterm delivery because they are still at risk in a subsequent pregnancy.

Principal Investigator

Aiyi Lui, Ph.D.

DIPHR Collaborators


  1. Boghossian NS, Yeung E, Albert PS, Mendola P, Laughon SK, Hinkle SN, Zhang C. Changes in diabetes status between pregnancies and impact on subsequent newborn outcomes. American Journal of Obstetrics and Gynecology. 210(5):431.e1-14, 2014. PMID: 24361790. PMCID: PMC4011935
  2. Boghossian NS, Yeung E, Mendola P, Hinkle SN, Laughon SK, Zhang C, Albert PS. Risk factors differ between recurrent and incident preeclampsia: a hospital-based cohort study. Annals of Epidemiology. 24(12):871-7e3, 2014. PMID: 25453345. PMCID: PMC4355246
  3. Hinkle SN, Albert PS, Mendola P, Sjaarda LA, Boghossian NS, Yeung E, Laughon SK. Differences in risk factors for incident and recurrent small-for-gestational-age birthweight: a hospital-based cohort study. BJOG. 121(9):1080-8; discussion 1089, 2014. PMID: 24702952. PMCID: PMC4108555
  4. Hinkle SN, Albert PS, Mendola P, Sjaarda LA, Yeung E, Boghossian NS, Laughon SK. The association between parity and birthweight in a longitudinal consecutive pregnancy cohort. Paediatric and Perinatal Epidemiology. 28(2):106-15, 2014. PMID: 24320682. PMCID: PMC3922415
  5. Laughon SK, Albert PS, Leishear K, Mendola P. The NICHD Consecutive Pregnancies Study: recurrent preterm delivery by subtype. American Journal of Obstetrics and Gynecology. 210(2):131.e1-8, 2014. PMID: 24036403. PMCID: PMC3934564
  6. Boghossian NS, Albert PS, Mendola P, Grantz KL, Yeung E. Delivery Blood Pressure and Other First Pregnancy Risk Factors in Relation to Hypertensive Disorders in Second Pregnancies. American Journal of Hypertension. 28(9):1172-9, 2015. PMID: 25673041. PMCID: PMC4542849
  7. Downes KL, Hinkle SN, Sjaarda LA, Albert PS, Grantz KL. Previous prelabor or intrapartum cesarean delivery and risk of placenta previa. American Journal of Obstetrics and Gynecology. 212(5):669.e1-6, 2015. PMID: 25576818. PMCID: PMC4416991
  8. Grantz KL, Hinkle SN, Mendola P, Sjaarda LA, Leishear K, Albert PS. Differences in risk factors for recurrent versus incident preterm delivery. American Journal of Epidemiology. 182(2):157-7, 2015. PMID: 26033931. PMCID: PMC4493980
  9. Shih JH, Albert PS, Mendola P, Grantz KL. Modelling the type and timing of consecutive events: application to predicting preterm birth in repeated pregnancies. Journal of the Royal Statistical Society: Series C (Applied Statistics). 64(5):711-30, 2015. PMID: 27239073. PMCID: PMC4879837
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