The first ultrasound scan after IVF: when to have it, and what it should show

The test is positive, the hCG levels have risen as expected, and yet many patients tell me they don’t dare believe it until they’ve ‘seen the heartbeat’. That is the purpose of the first ultrasound scan. If scheduled correctly, it answers almost all questions in one go. If carried out too early, it raises new questions and means you have to come back a week later.

When to schedule it

Most clinics recommend it between 6 and 7 weeks of pregnancy; several IVF units within the UK’s public healthcare system, for example, schedule it around 7 weeks. Following the transfer of a Day 5 blastocyst, this corresponds to approximately three to four weeks after the transfer, or two to three weeks after the positive blood test. The calculation of gestational age from the date of transfer is explained in the article on gestational age following IVF.

Before 6 weeks’ gestation, a gestational sac without a visible embryo is often seen; this is normal at this stage but can be distressing to hear. Waiting a few more days avoids the need for a second follow-up ultrasound scan and a week of worry.

What you can see, week by week

These figures are averages. A deviation of a few days from the theoretical timeline is common and, on its own, is not significant.

What the ultrasound scan checks

• Location. The gestational sac must be within the uterine cavity. An ectopic pregnancy remains possible following IVF, even when the embryo has been transferred into the uterus; this is the first thing to rule out.
• The number. How many sacs, how many embryos. A twin pregnancy is possible even after the transfer of a single embryo, if it splits; see one embryo or two.
• Cardiac activity and heart rate.
• The size of the embryo, measured from head to buttocks (crown-rump length), compared with the expected gestational age. As the date of IVF is precise, this comparison is more accurate than in a spontaneous pregnancy.

When the result is not yet clear

Sometimes, at the first ultrasound scan, a gestational sac without an embryo, or a small embryo without visible cardiac activity, may be seen. This is not a diagnosis. The reference criteria, derived from a consensus reached by the Society of Radiologists in Ultrasound and published in 2013 in the New England Journal of Medicine, are deliberately conservative so as never to terminate a developing pregnancy by mistake. A pregnancy is only deemed to have ceased if:

• the embryo measures 7 mm or more with no cardiac activity;
• the gestational sac measures 25 mm or more in mean diameter with no visible embryo;
• no embryo with cardiac activity appears two weeks or more after an ultrasound scan showing a gestational sac without a yolk sac, or eleven days or more after an ultrasound scan showing a gestational sac with a yolk sac.

In the UK, the NICE guidelines adopt the 7 mm and 25 mm thresholds, and recommend that, even beyond these, a second opinion or a second ultrasound scan be sought at least seven days apart before reaching a conclusion. Below these thresholds, the standard practice is to repeat the ultrasound scan, usually seven to fourteen days later. It takes a long time, but it is the only way to get a definitive answer. The risk of miscarriage, week by week, is detailed in a dedicated article; it decreases significantly once a heartbeat is visible.

Signs that do not require waiting for the ultrasound scan

Certain situations warrant seeking medical attention on the same day, either at the gynaecological A&E department or at your GP’s surgery, without waiting for the scheduled appointment: severe pain on one side of the lower abdomen, heavy bleeding, feeling unwell, or shoulder pain accompanied by abdominal pain. These are warning signs of an ectopic pregnancy. A small, isolated spot of bleeding, on the other hand, is common in the first trimester following IVF and does not necessarily indicate a miscarriage; report it to the clinic, which will decide whether to bring the ultrasound scan forward.

Where to have it done if you live far from the clinic

You do not need to return to Greece. The ultrasound scan can be carried out where you live, at your gynaecologist’s surgery or at an imaging clinic, using a transvaginal probe. Ask for a written report and send it to the Greek clinic, which remains your point of contact at this stage. To be useful, the report must state:

• the number of gestational sacs and their location;
• the presence of a yolk sac;
• the crown-rump length of the embryo;
• the presence and frequency of cardiac activity.

Further follow-up, once a doctor in your country has taken over, is described in the article on organising your return.

And what about treatment in the meantime?

Do not make any changes without the clinic’s advice. Progesterone, and oestrogen if you are on a hormone replacement (HRT) cycle, are generally continued until the end of the first trimester or thereabouts, depending on the protocol. The usual durations are detailed in the article on progesterone.

If you are unsure when to book the ultrasound scan or how to send the report, please write to me: I will liaise with the clinic.

Frequently asked questions

Source: https://fertilitegrece.com/en/blog/first-ultrasound-after-ivf/ — Triada Baloukoudis, IVF patient coordination in Greece. General information, not medical or legal advice. Printed on

Triada Baloukoudis
Independent IVF patient coordinator in Thessaloniki, with 24 years of experience supporting patients travelling from abroad. More · Contact · Facebook