Isolated low-normal amniotic fluid volume in the early third trimester: association with adverse perinatal outcomes.

AIMS: To test if an isolated finding of low-normal amniotic fluid index (AFI) in the early third trimester in low-risk patients is associated with adverse perinatal outcomes. METHODS: Retrospective cohort study with uncomplicated singleton pregnancies that had ultrasound studies between 28.0 and 31.9 weeks' gestation. Two cohorts with AFI 8.0-11.9 cm (low-normal, LN) and AFI 12.0-19.9 cm (mid-normal, MN) were compared. RESULTS: Patients with LN-AFI (n=99) were more likely to have early (<34 weeks) and late (<37 weeks) preterm birth (PTB) (relative risk 4.2 and 2.4, respectively) and a small for gestational age (SGA) infant (relative risk 1.8) than MN-AFI (n=834), corresponding to a higher NICU admission rate (relative risk 2.5). The risk of "spontaneous" PTB (preterm labor and rupture of membranes) did not differ between the cohorts, whereas the risk of "indicated" PTB (maternal or fetal indications) was significantly increased in LN-AFI. The incidence of abnormal antepartum testing, stillbirth, preeclampsia, placental abruption, fetal intolerance to labor, emergency cesarean delivery, umbilical artery pH <7.0, Apgar scores <7 at 5 min, and neonatal death was not increased in patients with LN-AFI. CONCLUSION: Low-normal AFI in the early third trimester increases the risk for subsequent delivery of an SGA infant and indicated PTB.

Emergence of late-onset placental dysfunction: relationship to the change in uterine artery blood flow resistance between the first and third trimesters.

OBJECTIVES: To test if emergence of third-trimester (T3) placental dysfunction is related to the impedance change in uterine artery blood flow resistance between the first trimester (T1) and T3. STUDY DESIGN: Mean T1 and T3 uterine artery (mUtA) pulsatility index (PI) was measured in 1098 singletons. Each patient's individual mUtA-PI change was calculated ([(T3 PI - T1 PI/interval in days)] × 100; ΔmUtA-PI). This parameter and T1 and T3 mUtA-PI z-scores were related to placenta-related disease (PRD) and to constitutionally small neonates (CS). RESULTS: Forty-seven (5%) women had PRD and 83 (8.7%) delivered a CS neonate. T1 and T3 mUtA-PI z-scores were higher with PRD (0.418 versus -0.097 and 1.06 versus -0.13, p < 0.001 for all). Change in mUtA-PI (ΔmUtA PI) was similar for patients with PRD. However, the prevalence of PRD doubled with rising ΔmUtA-PI (11.1% versus 5.2%, p = 0.041). CONCLUSION: T3 uterine artery Doppler performs significantly better in detecting patients at risk for late-onset PRD than T1 or the gestational age change in uterine artery Doppler resistance This suggests that a proportion of late emerging PRD is not amenable to early screening by uterine artery Doppler. Further research is essential to identify the optimal screening strategy for late-onset placental dysfunction.

First-trimester angiopoietin-2: relationships with maternal and placental characteristics.

Angiopoietin-2 (Ang-2), synthesized by endothelial cells, is a marker of placental vascular remodeling. Ang-2 is expressed in the first trimester, and levels may therefore correlate to other parameters of placental vascular development. The aim of this study was to evaluate the relationships between Ang-2 and other maternal/placental factors in the first trimester. This was a prospective observational study of women presenting for first-trimester screening at 11 + 0 to 13 + 6 weeks. Consenting women underwent an ultrasound, physical examination, and blood draw. Maternal serum Ang-2 levels were determined using enzyme-linked immunosorbent assay. Results were evaluated with relation to maternal age, parity, race, body mass index (BMI), mean arterial pressure (MAP), smoking/caffeine use, and parameters of placental blood flow resistance. In 111 consecutive patients, serum Ang-2 ranged from 0.6 to 10.9 ng/mL. Ang-2 levels were unrelated to maternal age, race, parity, smoking, and caffeine intake. Significant negative correlations were observed with BMI (Pearson's R = -0.325; P < 0.0001) and MAP (Pearson's R = -0.287; P = 0.002). Ang-2 levels did not correlate with gestational age (Spearman's rho, 0.064; P = 0.5058), but a significant positive correlation with the crown-rump length was observed (Spearman's rho, 0.261; P = 0.006). Neither uterine artery notching nor umbilical artery Doppler parameters correlated with Ang-2 levels. We concluded that Ang-2 as a marker of placental angiogenesis has significant relationships with maternal risk factors associated with abnormal placental development.

Serum pentraxin-3 levels at 11 to 14 weeks' gestation: association with maternal and placental characteristics.

OBJECTIVE: Pentraxin (PTX)-3 is an inflammatory molecule that may be increased in the first trimester in pregnancies with subsequent preeclampsia. We measured first-trimester serum PTX-3 and correlated levels with maternal/placental factors related to placental development. STUDY DESIGN: Prospectively enrolled women had ultrasound, physical examination, and blood draw at 11-14 weeks. PTX-3 determined by enzyme-linked immunosorbent assay was related to maternal age, parity, race, body mass index (BMI), mean arterial blood pressure (MAP), smoking/caffeine, and uterine/umbilical artery Doppler pulsatility index (PI). RESULTS: In 111 patients PTX-3 levels ranged from 0.2-13.8 ng/mL. Spearman correlation between PTX-3 and gestational age (rho = 0.096), maternal age (rho = -0.049), BMI (rho = -0.07), MAP (rho = -0.085), mean uterine artery PI (rho = 0.150), and umbilical artery PI (rho = -0.021) was nonsignificant (all P > .05). Similarly, PTX-3 distribution was unaffected by smoking/caffeine use, BMI >30, MAP >100 mm Hg, or uterine artery notching (P > .05 for all). CONCLUSION: First-trimester PTX-3 is unrelated to maternal characteristics and placental Doppler.