Risk of stillbirth in singleton fetuses with advancing gestational age at term: A 10-year experience of late third trimester prenatal screenings of 50,000 deliveries in a referral center in northern Italy

BACKGROUND

The risk of intrauterine death (IUD) at term varies from less than one to up to three cases per 1,000 ongoing pregnancies. The cause of death is often largely undefined. Protocols and criteria to prevent and define the rates and causes of stillbirth are the subjects of important scientific and clinical debates. We examined the gestational age and rate of stillbirth at term in a 10-year period at our maternity hub to evaluate the possible favorable impact of a surveillance protocol on maternal and fetal well-being and growth.

METHODS AND FINDINGS

Our cohort included all women with singleton pregnancies resulting in early term to late term birth at our maternity hub between 2010 and 2020, with the exclusion of fetal anomalies. As per our protocol for monitoring term pregnancies, all women underwent near term to early term maternal and fetal well-being and growth surveillance. If risk factors were identified, outpatient monitoring was initiated and early- or full-term induction was indicated. Labor was induced at late term (41+0-41+4 weeks of gestation), if it did not occur spontaneously. We retrospectively collected, verified, and analyzed all cases of stillbirth at term. The incidence of stillbirth at each week of gestation, was calculated by dividing the number of stillbirths observed that week by the number of women with ongoing pregnancies in that same week. The overall rate of stillbirth per 1000 was also calculated for the entire cohort. Fetal and maternal variables were analyzed to assess the possible causes of death.

RESULTS

A total of 57,561 women were included in our study, of which 28 cases of stillbirth (overall rate, 0.48 per 1000 ongoing pregnancies; 95% CI: 0.30-0.70) were identified. The incidence of stillbirth in the ongoing pregnancies measured at 37, 38, 39, 40, and 41 weeks of gestation was 0.16, 0.30, 0.11, 0.29, and 0.0 per 1000, respectively. Only three cases occurred after 40+0 weeks of gestation. Six patients had an undetected small for gestational age fetus. The identified causes included placental conditions (n = 8), umbilical cord conditions (n = 7), and chorioamnionitis (n = 4). Furthermore, the cases of stillbirth included one undetected fetal abnormality (n = 1). The cause of fetal death remained unknown in eight cases.

CONCLUSIONS

In a referral center with an active universal screening protocol for maternal and fetal prenatal surveillance at near and early term, the rate of stillbirth was 0.48 per 1000 in singleton pregnancies at term in a large, unselected population. The highest incidence of stillbirth was observed at 38 weeks of gestation. The vast majority of stillbirth cases occurred before 39 weeks of gestation and 6 of 28 cases were SGA, and the median percentile of the remaining case was the 35th.

The sFlt-1/PlGF Ratio in Patients Affected by Gestational Diabetes and SARS-CoV-2 Infection

Low values of the ratio of plasmatic soluble blocking factor FMS-like tyrosine Kinase 1 and placental growth factor (sFlt-1/PlGF) are required for an adequate placental angiogenesis and function. It has been shown that patients affected by gestational diabetes (GD) and patients with pneumonia from SARS-CoV-2 are characterized by an increased sFlt-1/PlGF ratio. The aim of the present study was to evaluate the sFlt-1-PlGF ratio in pregnancies complicated by COVID-19 and GD. We compared the plasmatic sFlt-1/PlGF ratio among the following groups of pregnant women: COVID-19, GD patients; COVID-19, non-GD patients; non-COVID-19, GD patients; and non-COVID-19, non-GD controls. We enrolled 62 women in the present study, who were divided as follows: 14 COVID-19, GD patients; 12 COVID-19, non-GD patients; 11 non-COVID-19, GD patients; and 25 non-COVID-19, non-GD controls. The COVID-19, GD patients presented a higher pre-pregnancy BMI, a higher prevalence of hypertensive disorders of pregnancy as a co-morbidity, and an increased need for medication for their diabetes. Neonatal data were similar between the groups. The controls showed a significantly lower sFlt-1/PlGF ratio compared to pregnancies complicated by GD and SARS-CoV-2 infection. The sFlt-1/PlGF ratio was higher in patients affected by both GD and SARS-CoV-2 infection; these subjects were characterized by a greater incidence of obesity and hypertensive disorders of pregnancy.

Hypertensive Disorders of Pregnancy and Fetal Growth Restriction: Clinical Characteristics and Placental Lesions and Possible Preventive Nutritional Targets

Background: The purpose of this study was to describe the placental lesions in pregnancies complicated by hypertensive disorders (HDP) and/or fetal growth restriction (FGR) and in uneventful control pregnancies. Methods: This is a case control study that included singleton pregnancies with HDP and normally grown fetus (HDP-AGA fetus), with HDP and FGR, early FGR, late FGR, and uneventful pregnancies. Feto-placental Doppler velocimetry and sFlt-1/PlGF ratio were performed. Placental histology was evaluated blinded according to the Amsterdam Consensus criteria. Results: Placental lesions with maternal vascular malperfusion (MVM) were significantly more frequent in HDP-FGR and early FGR (92% and 83%). MVM were significantly associated with abnormal feto-placental Doppler parameters, especially in early FGR. Delayed villous maturation (DVM) was associated with late FGR (83%). HDP-AGA fetus cases presented a heterogeneous pattern of placental lesions, including 60% of cases with MVM, but were not associated with abnormal Doppler feto-placental velocimetry. Conclusions: We found a prevalence of placental maternal vascular malperfusion in HDP-FGR and early FGR groups. These lesions were also associated with abnormal, anti-, and angiogenic markers. Conversely HDP-AGA fetus and late FGR presented more heterogeneous placental lesions not severe enough to cause feto-placental Doppler anomalies. These conditions are likely associated with different etiologies, such as maternal pre-pregnancy risk factors for metabolic syndrome. These findings suggest a possible preventive nutritional approach in addition to low-dose aspirin in pregnant women with predisposing factors for HDP-AGA fetuses and late FGR.

Assessing risk factors for severe forms of COVID-19 in a pregnant population: A clinical series from Lombardy, Italy

In 250 pregnant women with either asymptomatic, non‐severe, or severe SARS‐CoV‐2 infection, obesity turned out to be the main determinant of severe COVID‐19 illness.

Postnatal survival after endoscopic equatorial laser for the treatment of twin-to-twin transfusion syndrome

BACKGROUND

Endoscopic laser coagulation of placental anastomoses is the first-line treatment for severe twin-to-twin transfusion syndrome. A recent randomized controlled trial reported that laser coagulation along the entire vascular equator was associated with a similar dual survival and survival of at least 1 twin compared with the group that was treated with the selective technique. In addition, there was a significantly lower incidence of postoperative recurrence of twin-to-twin transfusion syndrome and the development of twin anemia-polycythemia sequence in the equatorial group.

OBJECTIVE

The purpose of this study was to report on neonatal survival in twin-to-twin transfusion syndrome pregnancies that were treated with endoscopic laser therapy with the use of the equatorial technique and to examine the relationship between preoperative factors and twin loss.

STUDY DESIGN

Endoscopic equatorial laser therapy was carried out as the primary treatment for twin-to-twin transfusion syndrome in all consecutive monochorionic diamniotic twin pregnancies that were referred at a single fetal surgery Center over a 4-year period. All visible placental anastomoses were coagulated; additional laser ablation of the placental tissue between the coagulated vessels was carried out. Pre-laser ultrasound data, periprocedural complications, pregnancy outcome, and postnatal survival at hospital discharge were recorded and analyzed.

RESULTS

A total of 106 pregnancies were treated during the study period. Median gestational age at laser therapy was 19.7 weeks (range, 15.1-27.6 weeks). There was postoperative recurrence of twin-to-twin transfusion syndrome or the development of twin anemia-polycythemia sequence in 2 (1.9%) and 2 (1.9%) cases, respectively. The survival rates of both and at least 1 twin were 56.6% and 83.0%, respectively. Donor survival was significantly lower compared with the recipient co-twin (64.2% vs 75.5%, respectively; P < .05). The rate of fetal death, which was the most common cause of twin loss, was significantly higher in donors compared with recipient fetuses (23.6% vs 10.4%, respectively; P < .05). In cases with absent or reversed end-diastolic velocity in the donor umbilical artery, dual and donor survival rates were significantly lower compared with the remaining twin-to-twin transfusion syndrome pregnancies (40.0% vs 64.8% and 40.0% vs 76.1%, respectively; P < .05). There were no significant differences between the 2 groups in the survival of at least 1 twin and in the recipient survival.

CONCLUSIONS

Endoscopic equatorial laser therapy was associated with a survival of both and at least 1 twin of approximately 55% and 83%, respectively, with a low rate of recurrent twin-to-twin transfusion syndrome and twin anemia-polycythemia sequence. In addition, the preoperative finding of abnormal donor umbilical artery Doppler on ultrasound identified a subgroup of twin-to-twin transfusion syndrome pregnancies with a lower dual survival rate caused by increased intrauterine deaths of donor twins.