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.
