Miscarriage is the most common complication of early pregnancy — in the general population, approximately 15–20% of clinically recognised pregnancies end in miscarriage. In IVF, the rates of early pregnancy loss can be higher, partly because IVF detects pregnancies (via blood hCG) at a stage where many natural conceptions would have ended before a woman even knew she was pregnant.
This guide explains the different forms of pregnancy loss that can occur after IVF, why they happen, and what the appropriate next steps are clinically and emotionally.
Types of Pregnancy Loss After IVF
Biochemical pregnancy: A positive hCG blood test (confirming the embryo implanted briefly and began producing hCG) followed by hCG levels that fall rather than rise. There is no visible pregnancy on scan. This is the earliest form of pregnancy loss — the embryo implanted but did not develop. Biochemical pregnancies after IVF are relatively common, particularly in older patients. See biochemical pregnancy after IVF.
Early miscarriage: A pregnancy confirmed on ultrasound (typically at 6–7 weeks, when a heartbeat should be visible) that subsequently ends. The most common type is a "missed miscarriage" (also called an incomplete or silent miscarriage) where the embryo stops developing but the body does not immediately expel the pregnancy — often discovered at a routine scan.
Late miscarriage: Pregnancy loss between 12 and 24 weeks is less common but clinically significant. It prompts more detailed investigation and different management.
Ectopic pregnancy: An IVF embryo (rarely) can implant outside the uterus, typically in the fallopian tube. Symptoms include one-sided pelvic pain and abnormal hCG rise. Ectopic pregnancy is a medical emergency. Any IVF patient with confirmed pregnancy and sudden one-sided pain should contact their clinic immediately.
Why Do Miscarriages Happen After IVF?
Chromosomal abnormality is the cause of the majority of miscarriages at all ages, and becomes more prevalent with age. An aneuploid (chromosomally abnormal) embryo may implant briefly and produce hCG (biochemical pregnancy) or implant and develop a heartbeat before development fails. This is not a failure of the uterus or the IVF process — it is a result of the egg or embryo having an incorrect chromosome number that is incompatible with ongoing development.
At 38–39, approximately 50–60% of embryos are aneuploid. At 42–43, this rises to over 75%. The elevated miscarriage rate in older patients reflects this biology directly.
Other causes include:
- Antiphospholipid syndrome (APS) — an immune condition causing abnormal clotting that can prevent the placenta from establishing properly. Treatable with low-dose aspirin and low-molecular-weight heparin.
- Uterine abnormalities — fibroids, polyps, or a septum in the uterus can prevent normal implantation.
- Thrombophilia — blood clotting disorders that increase miscarriage risk.
- Progesterone insufficiency — insufficient luteal phase support, though this is now standard to supplement during IVF.
What Investigation Is Appropriate?
After a single miscarriage, investigations are not routinely offered by most NHS providers — most single miscarriages are chromosomally driven events and do not indicate an underlying treatable cause.
After two miscarriages following IVF, or after one miscarriage in the context of IVF with suspected risk factors, investigation is more likely to be offered and is reasonable to request. Standard investigations include:
- Antiphospholipid antibody testing (lupus anticoagulant, anticardiolipin antibodies)
- Thrombophilia screen
- Chromosome karyotyping of both partners (to check for inherited chromosomal abnormalities)
- Uterine assessment (hysteroscopy or 3D ultrasound)
If the miscarried pregnancy tissue is available, karyotyping of the pregnancy can identify whether chromosomal abnormality was the cause — which provides important information for prognosis and future treatment planning.
For patients with recurrent miscarriage in the context of IVF, see recurrent miscarriage and IVF.
PGT-A After Miscarriage
PGT-A (preimplantation genetic testing for aneuploidies) tests embryos for chromosomal abnormalities before transfer. If chromosomal abnormality was the likely cause of a miscarriage, using PGT-A in a subsequent cycle can:
- Identify which embryos are chromosomally normal before transfer
- Reduce the probability of another chromosomally driven miscarriage
- Provide information about whether a cycle produces any euploid embryos
PGT-A is not appropriate in all situations — it adds cost, requires a freeze-all strategy, and slightly reduces the embryo cohort through the biopsy process. Discuss with your consultant whether it is appropriate for your specific case. See preimplantation genetic testing.
How Long Before Trying Again?
Most clinics recommend waiting at least one full menstrual cycle (approximately 4–6 weeks) before attempting another embryo transfer after a miscarriage. This allows the endometrium to recover and any retained tissue to clear.
After medical management (medication to help pass the pregnancy) or surgical management (ERPC — surgical evacuation), waiting at least one cycle is advised before transfer.
There is no evidence that waiting longer than one cycle improves outcomes — and for older patients, waiting significantly longer has a real cost. Discuss the timing of your next attempt with your consultant.
Emotional Support After Pregnancy Loss
Miscarriage in an IVF context is a compound loss: the loss of the pregnancy itself, and often a sense of lost time, investment, and hope. Grief after IVF pregnancy loss is legitimate and does not require minimising.
- Miscarriage Association: The UK's leading charity for miscarriage support, offering helplines and forums.
- Tommy's: Specialist charity with a helpline and NHS-linked miscarriage research clinics.
- SANDS (Stillbirth and Neonatal Death Society): For later losses.
Many fertility clinics also have counselling available — it is worth accessing this, particularly if you are considering whether to continue treatment.
Frequently Asked Questions
Q: I had a biochemical pregnancy after my first IVF transfer. Does that mean something is wrong?
A: Not necessarily. A biochemical pregnancy confirms the embryo implanted briefly — which is actually a positive sign about uterine receptivity. The loss is most commonly chromosomally driven. A single biochemical pregnancy after IVF is not typically grounds for investigation; it does, however, inform your understanding of the cycle and is worth discussing with your consultant.
Q: My hCG levels were rising but then fell. Is that a miscarriage?
A: Falling hCG levels after an initial positive test indicate that the pregnancy is not continuing — this is either a biochemical pregnancy or an early miscarriage. Contact your clinic immediately if your hCG levels are not rising as expected, both for clinical management and to rule out ectopic pregnancy.
Q: I was told my miscarriage was "bad luck." Is that accurate?
A: Often yes — the majority of single miscarriages are chromosomally driven events that do not indicate an underlying problem. However, if you are over 38, have had more than one miscarriage, or have risk factors (autoimmune conditions, a history of blood clotting issues), investigation is appropriate and "bad luck" is an insufficient explanation. Push for investigation if you are not satisfied.
Q: Can I use the frozen embryos from the cycle in which I miscarried?
A: Yes — a miscarriage does not affect frozen embryos from the same batch. After appropriate recovery time, you can proceed to a frozen embryo transfer with stored embryos. Discuss whether any protocol changes (endometrial preparation, aspirin, etc.) are warranted for the subsequent transfer.
Q: Do I need to tell my NHS GP about an IVF miscarriage?
A: Yes, particularly if you required medical or surgical management. Your GP should be informed and the event documented in your medical records. This is also important if you are receiving NHS-funded IVF — the outcome should be recorded.
This article is for information only and does not constitute medical advice. If you are experiencing a suspected miscarriage or ectopic pregnancy, contact your clinic immediately.