Exploring the relationship between preterm placental calcification and adverse maternal and fetal outcome.

OBJECTIVES

To explore the relationship between preterm placental calcification and adverse pregnancy outcome, including maternal and fetal outcomes.

METHODS

In this prospective cohort study, monthly ultrasonography was performed starting at 28 weeks' gestation to establish the diagnosis of Grade III placental calcification. Women were classified into three groups: Group 1, the early preterm group, with placental calcification found prior to 32 weeks (n = 63); Group 2, the late preterm group, with placental calcification found between 32 and 36 weeks (n = 192); and Group 3, the control group, without placental calcification noted between 28 and 36 weeks (n = 521). Women who smoked cigarettes or drank alcohol during pregnancy, or who had hypertension, diabetes, significant antenatal anemia or placenta previa were all excluded. Logistic regression analysis was used to estimate the risks of adverse pregnancy outcome in Groups 1 and 2 by calculating odds ratios (OR) with 95% CIs, adjusted by maternal age, body mass index, economic status, marital status, type of delivery and parity.

RESULTS

Risks for adverse maternal outcome including postpartum hemorrhage (OR, 3.43; 95% CI, 1.251-9.388), placental abruption (OR, 6.52; 95% CI, 1.356-31.382) and maternal transfer to the intensive care unit (OR, 9.76; 95% CI, 1.826-52.195) and for adverse fetal outcomes including preterm birth (OR, 4.20; 95% CI, 1.775-9.940), low birth weight (OR, 4.58; 95% CI, 2.201-9.522), low Apgar score (OR, 6.53; 95% CI, 2.116-20.142) and neonatal death (OR, 9.04; 95% CI, 1.722-47.411) were much higher in Group 1 than in Group 3. In contrast, there were no significant differences in adverse pregnancy outcome between Groups 2 and 3.

CONCLUSIONS

Early preterm placental calcification is associated with a higher incidence of adverse pregnancy outcome, and may serve as an indicator of adverse maternal and fetal outcomes when noted on ultrasonography. Conversely, women with late preterm placental calcification are not at greater risk for adverse pregnancy outcome.