Pulmonary Artery Doppler and Neonatal Outcome in Placenta Accreta Spectrum Patients

To correlate ultrasonographic markers of fetal lung maturity including Pulmonary artery Doppler indices in the late preterm and early term in placenta accreta spectrum patients with neonatal outcome.

The increasing rates of cesarean section has led to several fold increase in the incidence of placenta accreta spectrum in the last three or four decades.

Placenta accreta spectrum (PAS) disorders is the term used to describe a variety of pregnancy complications resulting from abnormal placental implantation that is accompanied by deﬁciency of the uterine wall.

Placenta accreta spectrum includes placenta accreta, placenta increta, placenta percreta.

Placenta accreta spectrum is one of the devastating obstetric complications owing to massive hemorrhage encountered during manual removal of the placenta to preserve the uterus or even the need for peripartum hysterectomy, need for massive blood transfusion, maternal intensive care admission and maternal mortality.

Complications related to blood loss are lower in elective compared to emergency deliveries. This has led to the scheduling of surgical interventions with planned late preterm (35-36 weeks) or early term (37 weeks) delivery as a mechanism to avoid the need for emergency surgery. According to the RCOG guidelines, planned delivery at 35 0/7- 36 0/7 weeks of gestation provides the best chance between fetal maturity and the risk of unscheduled delivery while ACOG recommends 34 0/7- 35 6/7.

Early attempts have been made to predict fetal maturity on the basis antenatal sonographic parameters including lung characteristics, bowel pattern, placental grading (which cannot be relied upon in patients with placenta accreta spectrum), and the presence or absence of intraamniotic particles (vernix caseosa).

Additionally, the epiphyseal ossification centers appear and enlarge at variable rates but in a predictable sequence: the distal femoral epiphysis (DFE) appears prior to the proximal tibial epiphysis (PTE), which precedes the appearance of the proximal humeral epiphysis (PHE). The PTE grows more rapidly than does the DFE so that, as gestation progresses, the size of the PTE approaches that of the DFE.

More recently, fetal pulmonary artery Doppler has been used to predict neonatal RDS. It was found that an elevated acceleration-to-ejection time ratio was significantly associated with neonatal RDS. However such indices cannot be generalized in all cases, especially those with placenta accreta spectrum who have excessive placental shunting affecting fetoplacental circulation resistance.

To the best of our knowledge, no available studies have correlated signs of maturity of the fetus detected by ultrasound with neonatal outcomes in the late preterm and early term in such patients. Presence of such signs of maturity can aid the obstetrician to choose the most appropriate timing for termination especially in low income countries who have limited access to NICUs.

Being cost effective and non invasive, ultrasonography is used as a routine obstetric scanning tool. This study will help determine the utility of ultrasound in assessing the fetal lung maturity in such patients.

Eligibility Criteria:
Inclusion Criteria:

* Age: 18-42 years old
* Patients who will be diagnosed with placenta accreta spectrum preoperatively according to (ACOG 2018), (Jauniaux et al., 2018 a), (Jauniaux et al., 2018 b)
* Those who will undergo elective or emergency cesarean.
* With gestational age: 34 0/7 - 38 6/7 weeks
* Under the effect of general anesthesia

Exclusion Criteria:

* Multifetal pregnancy
* Intrauterine fetal death
* Intrauterine growth restriction (IUGR) which is defined as a rate of fetal growth that is less than normal for the growth potential of that specific infant
* Diabetes with pregnancy either gestational or overt which is defined as any degree of glucose intolerance with an onset or first recognition during pregnancy
* Pregnancy induced hypertension defined as either systolic blood pressure ≥ 140 mmHg or diastolic blood pressure ≥ 90 mmHg. It is classified as one of four conditions: preexisting hypertension, gestational hypertension, preeclampsia, preexisting hypertension with superimposed preeclampsia
* Premature rupture of membranes
* BMI above 40 due to technical difficulties to obtain accurate measures
* Narcotic usage during anesthesia before fetal delivery
* Major congenital fetal anomalies whether diagnosed before or after delivery
* Maternal fever more than 37.4 degree
* Emergent cases presenting with fetal distress (bradycardia will be defined as fetal heart rate \< 110 beat per minute)
* Patients who have not completed the course of antenatal corticosteroids according to (RCOG 2010).
* Intraoperative spontaneous separation of the placenta