Nina Rodrigues Stein

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history

Preterm delivery is the main cause of neonatal death and ultrasonographic cervical assessment has been shown to be more accurate than digital examination in recognizing a short cervix. This is a cross-sectional study, involving 1131 women at 22-24 weeks of pregnancy, designed to determine the distribution of cervical length and to examine which variables of demographic characteristics and obstetric history increase the risk of a short cervix (15 mm or less). The distribution of maternal demographic and obstetric history characteristics among patients with cervical length pound 15 mm was analyzed and compared to the findings for the general population. Risk ratios (RR) between subgroups were generated from this comparison. Median cervical length was 37 mm and in 1.5% of cases it was 15 mm or less. The proportion of women with a short cervix (< or =15 mm) was significantly higher among patients with a low body mass index (RR = 3.5) and in those with previous fetal losses between 16-23 weeks (RR = 33.1) or spontaneous preterm deliveries between 24-32 weeks (RR = 14.1). We suggest that transvaginal sonographic measurement of cervical length be performed as part of a routine midtrimester ultrasound evaluation. There are specific variables of demographic characteristics and obstetric history which increase the risk of detecting a short cervix at 22-24 weeks.

Screening for Placental Insufficiency by Transvaginal Uterine Artery Doppler at 22–24 Weeks of Gestation

Objective: To determine the value of routine transvaginal color Doppler assessment of the uterine arteries at 22–24 weeks of gestation in the prediction of placental insufficiency. Methods: Women with singleton pregnancies scheduled for routine ultrasound scans at 22–24 weeks were offered Doppler assessment of the uterine arteries by transvaginal ultrasound. The pulsatility index (PI) was obtained for each artery and the mean value was calculated. A mean PI >95th percentile was considered increased. Screening characteristics for predicting placental insufficiency, defined as preeclampsia, fetal growth restriction or intrauterine death, were calculated. Results: Doppler examination of the uterine arteries was carried out in 1,057 singleton pregnancies. The mean uterine artery PI was 1.03 and the 95th percentile was 1.55. In 54 cases (5.1%) the mean PI was >1.55 (screen-positive). In the study population there were 48 cases of preeclampsia (5.1%), 72 fetal growth restrictions (7.5%) and 7 intrauterine deaths (0.7%). The screen-positive group showed an incidence of 47.1% of combined adverse results. The relative risks after a positive screening test were 7.3 (CI 4.2–12.6) for pre-eclampsia, 3.9 (CI 2.3 – 6.6) for fetal growth restriction and 4.5 (CI 3.2–6.4) for overall placental insufficiency. Conclusions: Uterine artery Doppler at 22–24 weeks identifies women at higher risk for the development of subsequent complications of placental insufficiency. This test could be used in combination with other markers to stratify the level of care offered in the third trimester of pregnancy.