Incompatibilités fœtomaternelles érythrocytaires

Risk factors for postpartum hemorrhage in pregnancies complicated by polyhydramnios

OBJECTIVE

To investigate the prevalence and the risk factors for postpartum hemorrhage (PPH) among pregnancies with polyhydramnios.

METHODS

We conducted a retrospective single-center study, including all women who presented with polyhydramnios, defined clinically as ≥ 2 L or by ultrasound with an Amniotic Fluid Index >25 cm or a Deepest Vertical Pocket >8 cm, from 2015 to 2022 at the Department of Gynecology and Obstetrics of Rouen University Hospital. We excluded cases of multiple pregnancies and preterm deliveries before 32 weeks of gestation. Our study population was divided into two groups based on the occurrence of PPH, defined as genital blood loss ≥500 ml within the first 24 h following childbirth. Maternal, gestational, and delivery characteristics were compared using univariate analysis. To explore an independent association between the studied factors and the risk of PPH, we performed a logistic regression model.

RESULTS

In our source population including all women from 2015 to 2022, there was a significant difference in the rate of PPH, which was 8.0 % among women with polyhydramnios (n = 35/437) compared to 5.1 % without (n = 1107/21,633, p = 0.01). In our study population based on polyhydramnios, among the 387 women included after application of exclusion criteria, 31 (8 %) of them experienced PPH. We found a significantly higher rate of failure to perform prophylactic oxytocin administration in the PPH group (2.3 % vs. 9.7 %, p < 0.05). We found a higher rate of cesarean section in the PPH group VS no PPH (43.5 % vs. 61.3 %, p = 0.06) but not significantly. After adjustment, our study found cesarean section as an independent risk factor for PPH (OR = 2.5, [1.1 - 5.8]), while prophylactic oxytocin was an independent protective factor against PPH (OR = 0.1, [0.1 - 0.4]).

CONCLUSION

In cases of polyhydramnios, cesarean section and the absence of prophylactic oxytocin administration are risk factors for PPH.

Anti-RH1 alloimmunization: At what maternal antibody threshold is there a risk of severe fetal anemia?

BACKGROUND

To define a threshold of maternal antibodies at risk of severe fetal anemia in patients followed for anti-RH1 alloimmunization (AI).

STUDY, DESIGN, AND METHODS

We conducted a retrospective study of patients followed for anti-RH1 AI at the Lille University Hospital. The first group, severe anemia, included patients who received one or more in utero transfusions (IUT) or who were induced before 37 weeks of pregnancy for suspected severe fetal anemia. The second group, absence of severe anemia, corresponded to patients without intervention during pregnancy related to AI. Sensitivities, specificities, and positive and negative predictive values for screening for severe fetal anemia were calculated for the antibody thresholds of 3.5 and 5 IU/ml for the quantification.

RESULTS

Between 2000 and 2018, 207 patients were included 135 in the severe anemia group and 72 in the no severe anemia group. No severe anemia was observed for an antibody titer below 16. For an antibody threshold of 3.5 IU/ml, the sensitivity was 98.2%, with 30.2% false positives. All severe anemias were detected in the second trimester; two cases of severe anemia were not detected in the third trimester. For an antibody threshold of 5 IU/ml, the sensitivity was lower at 95.6%, with five cases of severe anemia not detected.

CONCLUSION

The antibody threshold of 3.5 IU/ml for the quantification and 16 for the titration allow targeting patients requiring close monitoring by an experienced team in case of anti-RH1 AI.