The 6 Week Ultrasound Examination
Approximately 5 percent of IVF pregnancies will result in an
ectopic pregnancy, ie where the pregnancy implants outside the
uterine cavity. These pregnancies are non-viable and may cause
internal bleeding. Because of this risk an early diagnosis and
early treatment is important and for this reason all patients
are referred for an ultrasound examination following transfer
to assess the site of pregnancy implantation.
A pregnancy test is routinely performed on day 16 following
transfer. If this is positive a transvaginal ultrasound is
arranged, usually for 4 to 5 weeks following transfer. The site
, number and viability of the gestation(s) is / are documented.
At 6 weeks gestation (about 4 weeks following transfer)
a pregnancy sac, a yolk sac, an embryo and embryonic heart
motion should be visible. Delay in the appearance of these
individual structures may be an indicator of subsequent miscarriage.
Miscarriage occurs in 15-20% of IVF pregnancies and the
diagnosis is usually made upon inappropriately low hormone
levels in association with poor prognostic markers noted on
ultrasound. In many patients where signs of pregnancy failure
are present a repeat ultrasound examination is necessary before
a firm diagnosis of miscarriage can be made.
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