Doppler velocimetry and thrombophilic screening at middle trimester of gestation: preliminary data

To establish whether asymptomatic normotensive pregnant women with an abnormal uterine Doppler velocimetry, have haematological changes characteristic of congenital or acquired thrombophilia, and whether this information improve predict in pregnancy complications.

A prospective study involved the enrolment of 30 healthy normotensive pregnant women between the 23rd and 27th week of gestation, subdivided into group A (normal uterine Doppler velocimetry) and group B (abnormal uterine Doppler velocimetry). Besides uterine velocimetry (resistence index and presence/absence of notch), at enrolment in the study the PI of the umbilical artery and of the middle cerebral artery were measured, in addition to the usual foetal biometric parameters (biparietal diameter and abdominal circumference). Contemporaneously, a 20 ml blood sample was taken for the dosage of protein C, protein S, antithrombin III, activated protein C resistance, antiphospholipid antibodies and platelet functionality. Subsequently, for all the remaining period of the pregnancy, data were collected relating to the onset of any materno-foetal complications and modality of delivery, as well as neonatal data up to the first 20 days of life.

The incidence of adverse perinatal outcomes (pre-eclampsia, gestational hypertension, abruptio placentae, endouterine foetal death, preterm birth, caesarean section because of maternal or foetal problems, APGAR score lower than 7 at the 5th minute of life, small for gestational age) resulted as being 75% in group B versus 11% in group A (P<0.001). The mean gestational age at delivery was 34 weeks (range 27-41) in group A versus 39 weeks (range 37-42) in group B (P<0.001). No difference emerged as to either the mean activity in the plasma levels of the coagulation protein studied in patients with normal and abnormal uterine velocimetry. The same consideration is also true if the population is analysed in relation to the lesser or greater seriousness of the Doppler velocimetry abnormalities. Subdividing the patients in relation to the absence and to the presence of unfavourable perinatal outcomes, the thrombophilic indices appear to be substantially comparable.

Uterine Doppler velocimetry, carried out between the 24th and the 26th week of pregnancy, proves its validity by identifying a population at high risk of adverse perinatal outcomes. In contrast, the investigations carried out on the haematological abnormalities characteristic of thrombophilia do not reveal any significant differences, either between patients with normal and those with abnormal velocimetry, or between patients with adverse perinatal outcomes and those without. It is thus unlikely that these preliminary data will lead to an improvement in the clinical reliability of uterine velocimetry.