BACKGROUND:

• Data to help counsel patients with twins about risk for preterm birth are limited
• Easter et al. (American Journal of Perinatology, 2018) assessed the relationship between preterm birth in a prior pregnancy and preterm birth in a twin pregnancy

METHODS:

• Secondary analysis of MFMU Network randomized controlled trial (RCT)
  • Primary study was designed to evaluate 17-α-hydroxyprogesterone caproate in twins
• Participant eligibility
  • Twin gestations between 16w0d to 20w6d
• Participant exclusion
  • For this study, only exclusion was selective reduction
• Obstetric history was classified as follows
  • Nulliparous: 0 prior deliveries <20 weeks
  • Multiparous with a prior term birth: Delivery ≥37 weeks without prior preterm delivery
  • Multiparous with a prior preterm birth: Any delivery between 20w0d and 36w6d
• Primary outcome
  • Rate of spontaneous preterm birth <35 weeks in the current twin pregnancy
• Secondary outcomes
  • Rates of spontaneous and any preterm birth <28 and <35 weeks
  • Spontaneous delivery <24 and <22 weeks’ gestation

RESULTS:

• 653 women analyzed
  • 294 nulliparas | 310 prior term birth | 49 prior preterm birth
• Absolute rates of spontaneous preterm birth >35 weeks
  • 28.23% in nulliparous vs 55.10% in those women with prior preterm birth (p < 0.01)
• Prior preterm birth increased the likelihood of spontaneous delivery before 35 weeks
  • Adjusted odds ratio (aOR): 2.44; 95% CI, 1.28–4.66
• Prior term delivery decreased likelihood of spontaneous delivery before 35 weeks
  • aOR: 0.55; 95% CI, 0.38–0.78 compared with the nulliparous reference group
• Women with a prior term delivery had lower odds of composite neonatal morbidity
  • aOR: 0.38; 95% CI, 0.27–0.53

CONCLUSION:

• For women with twin pregnancies, previous preterm birth increased risk of spontaneous preterm birth while previous term delivery decreased the likelihood

Learn More – Primary Sources:

Obstetric History and Likelihood of Preterm Birth of Twins

Related ObG Topics:

SMFM Statement: Choice of Progestogen for Preterm Birth Prevention

Preventing Preterm Birth in Twins – What works?

Vaginal Progesterone to Prevent Preterm Birth in Twins

Antepartum Corticosteroids – When to Administer?

Does the Timing of a Loss of One Twin Affect the Risk for Preterm Birth?