Clinical phenotypes for risk stratification in small-for-gestational-age fetuses

OBJECTIVE

To evaluate whether clinical phenotypes of small-for-gestational-age (SGA) fetuses can be identified and used for adverse perinatal outcome risk stratification to facilitate clinical decision-making.

METHODS

This was a multicenter observational cohort study conducted in two tertiary care university hospitals. SGA fetuses were classified according to maternal, fetal and placental conditions using a two-step cluster algorithm, in which fetuses with more than one condition were assigned to the cluster associated with the highest mortality risk. Delivery and perinatal outcomes were compared using chi-square test among SGA clusters, and the associations between outcomes and each cluster were evaluated by calculating odds ratios (OR), adjusted for gestational age.

RESULTS

The study included 17 631 consecutive singleton pregnancies, of which 1274 (7.2%) were defined as SGA at birth according to INTERGROWTH-21^st standards. Nine SGA clinical phenotypes were identified using a predefined conceptual framework. All delivery and perinatal outcomes analyzed were significantly different among the nine phenotypes. The whole SGA cohort had a three-times higher risk of perinatal mortality compared with non-SGA fetuses (1.4% vs 0.4%; P < 0.001). SGA clinical phenotypes exhibited three patterns of perinatal mortality risk: the highest risk was associated with congenital anomaly (8.3%; OR, 17.17 (95% CI, 2.17-136.12)) and second- or third-trimester hemorrhage (8.3%; OR, 9.94 (95% CI, 1.23-80.02)) clusters; medium risk was associated with gestational diabetes (3.8%; OR, 9.59 (95% CI, 1.27-72.57)), preterm birth (3.2%; OR, 4.65 (95% CI, 0.62-35.01)) and intrauterine growth restriction (3.1%; OR, 5.93 (95% CI, 3.21-10.95)) clusters; and the lowest risk was associated with the remaining clusters. Perinatal mortality rate did not differ between SGA fetuses without other clinical conditions (54.1% of SGA fetuses) and appropriate-for-gestational-age fetuses (0.1% vs 0.4%; OR, 0.41 (95% CI, 0.06-2.94); P = 0.27). SGA combined with other obstetric pathologies increased significantly the risk of perinatal mortality, as demonstrated by the increased odds of perinatal death in SGA cases with gestational diabetes compared to non-SGA cases with the same condition (OR, 24.40 (95% CI, 1.31-453.91)).

CONCLUSIONS

We identified nine SGA clinical phenotypes associated with different patterns of risk for adverse perinatal outcome. Our findings suggest that considering clinical characteristics in addition to ultrasound findings could improve risk stratification and decision-making for management of SGA fetuses. Future clinical trials investigating management of fetuses with SGA should take into account clinical information in addition to Doppler parameters and estimated fetal weight. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Effect of parity on maternal cardiac function during the first trimester of pregnancy

OBJECTIVE

To investigate maternal cardiac adaptation in the first trimester of pregnancy with increasing maternal parity.

METHODS

This was a cross-sectional study carried out at the antenatal clinic of a teaching hospital. We examined 4689 pregnant women at 11 + 0 to 13 + 6 weeks of gestation, performing two-dimensional echocardiography of the maternal left ventricle. There were 2352 parous and 2337 nulliparous women. The relationships between parity, maternal cardiac function and neonatal birth weight were analyzed.

RESULTS

Parous compared to nulliparous women had a significantly higher median cardiac output (5.6 vs. 5.2 L/min) and median cardiac index (2.3 vs. 2.1 L/min/m(2)). This was owing to a significantly higher median stroke volume (73.5 vs. 70.5 mL), heart rate (76 vs. 75 bpm), left ventricular outflow diameter (20.4 vs. 20.0 mm) and lower total vascular resistance (1190.8 vs. 1253.7 dyne s/cm(5)) and median uterine artery pulsatility index (1.6 vs. 1.7). Mean arterial blood pressure was not significantly different between the groups. There was a progressive increase in all maternal cardiac variables, apart from total peripheral resistance, which decreased with increasing parity. Birth weight was higher in parous compared to nulliparous women (3.39 vs. 3.23 kg) and it was independently related to maternal hemodynamic variables and demographic and social characteristics (age, height, weight, ethnicity, smoking).

CONCLUSION

Pregnancy in parous compared to nulliparous women is characterized by higher maternal cardiac output and birth weight.