Fetal hemodynamics evaluated by Doppler velocimetry in the second half of pregnancy.

The objective of our study was to assess fetal hemodynamics by Doppler velocimetry during the second half of pregnancy. We carried out a longitudinal study on 33 normal fetuses between the 22nd and 38th weeks of gestation. Doppler velocimetry was performed in the aorta, suprarenal (SRA) and infrarenal (IRA) segments, middle cerebral artery (MCA) and umbilical artery (UA), on the basis of fetal peak systolic velocity (SV), end-diastolic velocity (DV) and resistance index (RI). We used a sample volume of 1 mm, a wall filter of 50 to 100 Hz, a 5 degrees to 19 degrees insonation angle in the MCA and UA, and below 60 degrees in the SRA and IRA. Between the 22nd and 38th weeks of gestation, SV and DV increased in all fetal arteries (p<0.05), but SV decreased in the UA from 52.5 to 46.2 cm/s between the 34th and 38th gestational weeks (p<0.05). The RI was unchanged in the SRA and throughout most of the gestational weeks in the IRA (p>0.05), but decreased from 0.69 to 0.56 in the UA (p<0.05). In the MCA, it decreased from 0.85 to 0.75 between the 26th and 38th gestational weeks (p<0.05). In conclusion, the volume of blood flow in the fetal organs necessary for their development is related to increased SV and DV and to decreased RI. The Doppler velocimetry measurements for normal fetuses could be compared with those for fetuses in high-risk pregnancies.

Uterine volume in adolescents.

The objective of the present study was to determine the uterine volume of adolescents by ultrasonography, and to correlate it with pregnancy during adolescence and with the immaturity of the female genital tract for pregnancy and delivery. A transverse observational study was conducted on 828 patients who were 10 to 40 years old by transabdominal ultrasonography and were divided into two groups: group 1 consisted of 477 (57.6%) adolescents and group 2 consisted of 351 (42.3%) women 20 to 40 years old. Uterine volume increased with the presence of menarche, age and parity (p < 0.05). Nulliparous and primiparous adolescents younger than 18 years old had a smaller uterine volume, 41.3 +/- 17.9 and 51.6 +/- 19.7 cm(3), respectively, than nulliparous and primiparous women 20 to 40 years old (p < 0.001). However, secundiparous adolescents had a uterine volume of 62.6 +/- 20.6 cm(3), which was significantly similar to the uterine volume of women 20 to 40 years old (p = 0.22). The differences in uterine volume between adolescents younger than 18 years old or with less than two deliveries and women who were 20 to 40 years old may be due to immaturity of the female genital tract for pregnancy and delivery among younger women, with a consequent higher incidence of preterm deliveries in this group.