Fetal pulmonary hemodynamics: Doppler reference values in low risk pregnancies.

OBJECTIVE: To investigate fetal pulmonary hemodynamics in normal pregnancy using pulsed and color Doppler ultrasonography and to define Doppler reference ranges values in the whole fetal pulmonary circulation during different gestational ages. MATERIALS AND METHODS: A prospective observational study was conducted to evaluate 190 healthy singleton pregnancies between 20 and 38 weeks of gestation, including 10 cases for each gestational age. The main pulmonary artery, right pulmonary artery, left pulmonary artery, ductus arteriosus and pulmonary veins waveforms were evaluated. The waveform profile was studied for each pulmonary vessel investigated. We calculated the normal distribution of data of 12 Doppler parameters, their values were expressed as 5th, 25th, 50th, 75th and 95th centile. RESULTS: We report several pulmonary hemodynamic changes with the progression of pregnancy. We focused on the hemodynamic values of the parameters most useful in clinical practice and that would better describe the hemodynamic events of this vascular district. CONCLUSION: This study reports a complete description of the fetal pulmonary hemodynamics at different gestational ages. Many hemodynamic parameters show a typical change during gestation. The reference ranges described in this study may help in situations where is indicated to evaluate the pulmonary hemodynamics and to identify healthy fetuses from those affected by pathological conditions related mainly to fetal cardiovascular anomalies and/or feto-maternal pathologic conditions.

Does fetal sex affect pregnancy outcome?

BACKGROUND: In maternal fetal medicine, gender differences in outcome are often observed. OBJECTIVE: This article reviews the fetal sex-dependent differences found in many aspects of pregnancy, from conception through birth. METHODS: The MEDLINE, EMBASE, and Current Contents databases were searched, for the years 1985 to 2006, using the following Medical Subject Headings and text words: fetal gender, finale, female, sex ratio at birth, pregnancy outcome, preterm birth, and stillbirth. The search was not limited by language. In addition, the bibliographies of known relevant articles were examined to capture any reports not already identified in the electronic search. All reports that provided information on gender differences in pregnancy outcome were included for review. RESULTS: An extremely high male-to-female ratio was found in fetuses born after very short-duration pregnancy; this level declined around the 20th week and stabilized at term. In the absence of manipulation, both the sex ratio at birth and the population sex ratio have been found to remain consistent. A higher incidence of preterm birth and premature preterm rupture of membranes has been observed in different populations among mothers of male newborns compared with mothers of females. It has been speculated that this higher incidence may be linked to the relatively greater weight at lower gestational age of male newborns versus females. Women carrying male fetuses had higher rates of gestational diabetes mellitus, fetal macrosomia, failure to progress during the first and second stages of labor, cord prolapse, nuchal cord, and true umbilical cord knots. Cesarean sections were also more frequently found among male neonates compared with females. CONCLUSIONS: Male sex is an independent risk factor for adverse pregnancy outcome. Evidence suggests that females have an advantage over males, with a better outcome in the perinatal period, particularly after preterm birth.