حاسبة خطر الإجهاض

Miscarriage risk falls steeply through the first trimester and rises with maternal age, and those two facts are what any risk figure is built from. It is worth being clear about what such a number can and cannot do: it describes what happens across a large population of pregnancies at a given point, and it cannot tell any individual whether their own pregnancy will continue.

How risk changes with gestational age

The steep decline through the first trimester is the most useful pattern here. Most losses occur early and are caused by chromosomal abnormalities that arose at conception, which is why risk drops sharply once a pregnancy has been shown to be developing normally. A confirmed fetal heartbeat on ultrasound is the single largest reduction in risk in early pregnancy.

• A very large proportion of conceptions are lost before a test would ever turn positive. These are not experienced as miscarriages and are not included in the commonly quoted figures.
• Figures vary between studies depending on how early pregnancies were detected and which losses were counted, so treat any single number as approximate.

How risk changes with age

Maternal age is the strongest single predictor, and the mechanism is well understood: the proportion of eggs with chromosomal abnormalities rises with age, and most early losses are chromosomal. The pattern is a gentle rise through the thirties and a steep one after about 40.

• Paternal age has a smaller but measurable independent association.
• These are population figures. Two people of the same age with the same history can have very different outcomes, and the number does not distribute itself evenly across individuals.

What this does not mean

The single most important thing to say on a page like this is that miscarriage is almost never caused by anything the pregnant person did. Ordinary activity, exercise, working, sex, lifting, stress, a glass of wine before knowing, and travel are not causes. The overwhelming majority of first-trimester losses are chromosomal events determined at conception and were not preventable.

Recurrent loss is treated differently from a single event. Investigation is usually offered after two or three consecutive losses, and looks for the small number of identifiable and sometimes treatable causes: chromosomal rearrangements in either partner, antiphospholipid syndrome, uterine structural abnormalities and thyroid disease. Even after full investigation, no cause is found in roughly half of cases, and the outlook for a subsequent pregnancy remains good.

• Bleeding in early pregnancy is common and does not necessarily mean miscarriage, but it should always be reported to a clinician.
• Severe or one-sided pain, shoulder-tip pain, or faintness with bleeding needs emergency assessment for ectopic pregnancy.

حدود الاستخدام

• These are population statistics. They cannot predict the outcome of an individual pregnancy, and a low number is not reassurance nor a high one a prediction.
• Published figures vary considerably depending on how early pregnancies were detected, which losses were counted, and the population studied.
• The age figures describe maternal age only and do not incorporate the many other factors that modify risk.
• The calculator cannot account for individual medical history, previous losses, known chromosomal or uterine factors, or current symptoms.
• It has no diagnostic function whatsoever. Only clinical assessment and ultrasound can evaluate a specific pregnancy.
• Any bleeding or pain in pregnancy should be assessed by a clinician rather than interpreted against a statistical table.

الأسئلة الشائعة

What is the risk of miscarriage by week?

Risk falls steeply through the first trimester. From a positive test the risk is roughly 1 in 5; once a heartbeat is seen at 6 weeks it commonly drops to around 10 percent, by 8 weeks to around 3 to 5 percent, and after 12 weeks to around 1 to 2 percent.

How does age affect miscarriage risk?

Risk rises from around 10 percent under 30 to around 20 percent at 35 to 39, around 40 percent at 40 to 44, and over 50 percent at 45 and above. The driver is the rising proportion of eggs with chromosomal abnormalities.

Did I do something to cause my miscarriage?

Almost certainly not. Ordinary activity, exercise, work, sex, lifting, stress and travel do not cause miscarriage. The large majority of first-trimester losses are chromosomal events determined at conception and were not preventable.

Does seeing a heartbeat mean the pregnancy is safe?

It substantially reduces the remaining risk but does not eliminate it. A heartbeat at 8 weeks is associated with a remaining risk commonly cited around 3 to 5 percent, compared with roughly 20 percent before any scan.

When should recurrent miscarriage be investigated?

Investigation is usually offered after two or three consecutive losses. It looks for chromosomal rearrangements, antiphospholipid syndrome, uterine abnormalities and thyroid disease. No cause is found in roughly half of cases, and the outlook for a future pregnancy remains good.

المراجع

1. American College of Obstetricians and Gynecologists. Early Pregnancy Loss.
2. MedlinePlus. Miscarriage.
3. MedlinePlus. Miscarriage: overview.
4. MedlinePlus. Ectopic pregnancy.