Miscarriage after IVF: why it happens and what comes next

Early pregnancy loss is the most common unwanted event in reproductive medicine. Roughly 10 to 20 per cent of pregnancies confirmed by ultrasound or β-hCG end before 12 weeks, and the proportion rises clearly with a woman’s age: it is lower under 30 and can exceed half of pregnancies after 40. Many further losses happen even earlier, before a woman knows she is pregnant. After IVF these losses are recorded more often because pregnancy is diagnosed within days, whereas in spontaneous pregnancies a share passes unnoticed.

The main cause is not something that happened during the pregnancy but something present from the beginning: a random abnormality in the embryo’s chromosomes. This mechanism explains about half or more of first-trimester losses and becomes more frequent with age, because eggs accumulate the risk of errors during division over time. These abnormalities arise by chance and, in the overwhelming majority of cases, are not inherited from the parents.

Almost every patient looks for the cause in herself, and this list deserves to be stated plainly. Everyday stress, a hard week at work, a family argument or the anxiety of waiting do not cause miscarriage. Nor does lifting a heavy bag, cleaning the house, walking or working. An ultrasound scan, including a transvaginal one, is safe in pregnancy. Sexual intercourse does not end a normal pregnancy. A flight, a cup of coffee a day or a meal you ate are not responsible.

The transfer technique is not a cause either. The embryo does not fall out and is not damaged when you get up from the table, cough or go to the toilet; it sits inside the closed space of the uterus. When a pregnancy after transfer is lost, the reason in most cases is the biology of that embryo, not the procedure and not anything you did. This does not lessen the pain, but it removes blame from a place where it does no good at all.

When a scan confirms the pregnancy is not continuing, there are three routes and all three are medically acceptable in most situations. Expectant management means giving the body time to complete the process on its own, usually within two to four weeks, with bleeding and cramping like a heavy period. Medical management uses medication that brings the process on within a day or two. A minor surgical procedure, known as aspiration or curettage, empties the uterus in a few minutes, usually under a short anaesthetic.

The choice depends on the clinical picture, how far the pregnancy had progressed, the bleeding, your history and, just as much, your preference. Surgery offers predictable timing and the option of genetic analysis of the tissue where that is useful; expectant management avoids an anaesthetic. Whichever route you choose, the team will explain the signs of excessive bleeding or infection that need immediate contact.

According to the ESHRE guideline on recurrent pregnancy loss, full investigation is recommended after two or more losses. It includes antiphospholipid antibodies, thyroid function, assessment of the uterine cavity with three-dimensional ultrasound, saline sonography or hysteroscopy, and in selected cases parental karyotype or analysis of the pregnancy tissue. Many tests marketed online, such as broad immunological panels or NK cell testing, are not recommended because they do not change treatment. After a single loss, investigations rarely give an answer and the chances for the next pregnancy remain good.

For the next cycle: if you have frozen embryos, they remain usable and their quality has not changed. Usually one or two menstrual cycles are enough for the endometrium to recover and for β-hCG to fall; a long wait is not needed. Genetic testing of embryos, PGT-A, is not routinely recommended after a loss, because it does not increase the cumulative live birth rate. Time for emotional support, for you and your partner, is part of the plan and not an optional extra.