The diagnostic and therapeutic role of ultrasound in obstetrics

Advances in ultrasound technology and new developments in the field of screening for pregnancy disorders have led to a change in the clinical application of ultrasound in the care of women with normal and complicated pregnancies. This review highlights the validated uses of ultrasound in obstetrics, such as pregnancy dating, screening for aneuploidy, diagnosis of foetal abnormality, placental localization, diagnosis of chorionicity in multiple pregnancy, assessment of foetal growth and well-being and foetal therapy. Knowledge of the scientific basis of the role of ultrasound means more appropriately timed intervention in pathological pregnancies.     

Effect of first-trimester serum from pregnant women with high-resistance uterine artery Doppler resistance on extravillous trophoblast invasion

BACKGROUND: Abnormal uterine artery Doppler indices are associated with pregnancy complications such as pre-eclampsia and intrauterine growth restriction. Poor trophoblast invasion may be a consequence of, or be associated with, abnormal Doppler indices. OBJECTIVE: To evaluate in vitro trophoblast function following exposure to first-trimester serum from pregnancies with high uterine artery Doppler resistance indices. METHODS: Doppler ultrasound examination of the maternal uterine arteries was performed on women at 10-14 weeks' gestation. Serum was collected from women with bilateral uterine artery notches with resistance indices above the 95th centile and from patients with normal uterine artery indices. The effect of serum on trophoblast invasion was determined using an established in vitro model from the extravillous trophoblast-derived cell line SGHPL-4. RESULTS: Trophoblastic invasion was significantly reduced when treated with serum from women with high-resistance compared with normal-resistance uterine artery Doppler indices (P < 0.05). CONCLUSION: Maternal serum in the first trimester of pregnancy from patients with high-resistance uterine artery Doppler indices appears to inhibit trophoblast invasion. This experimental model allows further investigation of factors responsible and the evaluation of therapeutic strategies.     

Defective endovascular trophoblast invasion in the first trimester is associated with increased maternal serum ischemia-modified albumin

BACKGROUND: Ischemia-modified albumin (IMA), a protein elevated in cardiac ischemia, is also increased to supra-physiological levels in early normal pregnancy. This finding supports the hypothesis that normal trophoblast development is stimulated by a hypoxic intrauterine environment. The aim of this study was to examine whether first trimester IMA levels are further elevated with defective trophoblast development. METHODS: Prospective study of healthy women with singleton pregnancies undergoing nuchal translucency assessment at 11-14 weeks. First trimester maternal serum IMA concentrations in those subsequently developing pre-term pre-eclampsia (n = 19) were compared to randomly chosen controls with normal pregnancy outcome (n = 69). RESULTS: Median first trimester serum IMA concentrations were significantly higher in women who subsequently developed pre-eclampsia (median 126.5 kU/L, interquartile range (IQR) 114.33-134.36 kU/L) when compared to those with normal pregnancy outcome (median 115.01 kU/L, IQR 102.29-124.81 kU/L, P = 0.02). CONCLUSIONS: Maternal serum IMA levels are elevated in the first trimester in women with pre-eclampsia, a clinical manifestation of defective endovascular trophoblast development. This suggests that abnormally high intrauterine hypoxia and subsequent reperfusion oxidative damage may be associated with defective trophoblast development. First trimester serum IMA may be a potential biomarker for abnormal placental development.     

Prospective risk of stillbirth in multiple-gestation pregnancies: a population-based analysis

OBJECTIVE: To evaluate the prospective risk of stillbirth in multiple gestations. METHODS: We conducted a retrospective analysis of birth notifications and infant mortality records relating to all multiple gestations to residents in a predefined health district. The incidence of live births and stillbirths was used to calculate the prospective risk of stillbirth at each week of gestation. RESULTS: The risk of stillbirth in multiple gestations increased from 1:3333 at 28 weeks' gestation to 1:69 at 39 or more weeks' gestation. The stillbirth risk in multiple gestations at 39 weeks surpassed that of postterm singleton pregnancies (1:526). CONCLUSION: Multiple gestations at 37-38 weeks have a risk of stillbirth equivalent to that of postterm singleton pregnancy. Because multiple gestations rarely proceed beyond 39 weeks, and because stillbirth risk increases several-fold beyond this stage, elective delivery might be justified at this gestational age.     

Agreement between predicted risk and prevalence of Down syndrome in first trimester nuchal translucency screening

The agreement between predicted risks of Down syndrome and observed prevalence was investigated in a population of 11,847 singleton pregnancies screened by first trimester nuchal translucency at a single institution. Twenty-seven cases of Down syndrome were observed; 20 were detected prenatally by nuchal translucency and maternal age screening, three by other means and four postnatally. The screened women were grouped according to their predicted risk of having an affected pregnancy, and this was compared with the observed prevalence. A significant correlation between predicted and observed prevalences was noted, thus demonstrating that risk estimates for Down syndrome based on first trimester nuchal translucency screening are accurate.