Pulmonary Artery Doppler And Neonatal Outcome In Hypertensive Disorders Of Pregnancy

Hypertensive disorders include gestational hypertension, preeclampsia, chronic hypertension, preeclampsia superimposed on chronic hypertension. They complicate up to 10% of pregnancies. As a group they are one member of the deadly triad, along with hemorrhage and infection, that contributes greatly to maternal morbidity.

Preeclampsia, either alone or superimposed on chronic hypertension, is the most dangerous. Most hypertension related deaths are preventable. Also, nonsevere preeclampsia may progress rapidly to severe disease causing headache or visual disturbance that precede eclampsia. They also cause epigastic or right upper quadrant pain and elevated hepatic transaminases that frequently accompany hepatocellular necrosis, ischemia and edema, thrombocytopenia that represents platelet activation and aggregation, microangiopathic hemolysis, renal involvement and placental abruption. On the long term, preeclampsia is also associated with adverse health problems including chronic hypertension, ischemic heart disease, atherosclerosis, cardiomyopathy, peripheral vascular disease, type 2 diabetes, dyslipidemia, obesity and metabolic syndrome.

Termination of pregnancy is the only known cure for preeclampsia. Moreover, expectant management of preterm severe preeclampsia leads to disastrous results as increase in perinatal mortality rate, placental abruption, eclampsia, renal failure, hypertensive encephalopathy, intracranial hemorrhage or even rupture in hepatic hematoma.

Early attempts have been made to predict fetal maturity on the basis antenatal ultrasonographic parameters including lung characteristics, bowel pattern, placental grading, the presence or absence of intraamniotic particles (vernix caseosa) and the epiphyseal ossification centers appearance and enlargement.

More recently, fetal pulmonary artery Doppler has been used to predict neonatal respiratory rate (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 hypertensive disorders of pregnancy who have abnormal trophoblastic invasion of uterine vessels affecting fetoplacental circulation resistance.

To the best of our knowledge, no available studies have correlated fetal pulmonary artery Doppler indices with neonatal outcomes in patients with hypertensive disorders of pregnancy. 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 neonatal intensive care units. Being cost effective and non invasive ultrasonography is used as a routine obstetrics scanning tool. This study will help determine the utility of ultrasound and Doppler in assessing the fetal lung maturity in such patients.

Inclusion criteria

• Age: 18-42 years old
• Patients who will be diagnosed with hypertensive disorders of pregnancy preoperatively according to (ACOG 2020)
• Those who will undergo elective or emergency termination of pregnancy whether by vaginal or cesarean delivery .
• Primi or multigravida
• With gestational age: 28 0/7 - 37 6/7 weeks

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
• Placental abruption whether diagnosed before or during delivery.
• Absent or reversed umbilical artery end diastolic flow.
• Diabetes with pregnancy either gestational or overt which is defined as any degree of glucose intolerance with an onset or first recognition during pregnancy
• Premature or prelabor rupture of membranes
• BMI above 40 due to technical difficulties to obtain accurate measures
• 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)
• Patient receiving general anesthesia if termination was by cesarean delivery
• Patients receiving narcotics 4 hours before delivery
• Patients with unreliable dates or no crown rump length at first trimester.