On the NHS you are offered booking bloods early in pregnancy — ideally before 10 weeks — to check your blood count, blood group and rhesus status, screen for hepatitis B, HIV and syphilis, and for sickle cell and thalassaemia. Further blood tests follow with the 12-week scan (the optional combined test) and at around 28 weeks, plus a glucose tolerance test at 24–28 weeks if you have risk factors.
| Category | Reference range |
|---|---|
| Sickle cell and thalassaemia screening | ideally before 10 usual NHS timing (weeks of pregnancy) |
| Booking bloods: FBC, blood group, rhesus, antibodies | 8–12 (often earlier) usual NHS timing (weeks of pregnancy) |
| Hepatitis B, HIV, syphilis | 8–12 usual NHS timing (weeks of pregnancy) |
| Combined test (blood + nuchal scan) | 11–14 usual NHS timing (weeks of pregnancy) |
| Quadruple test, if combined test not possible | 14–20 usual NHS timing (weeks of pregnancy) |
| OGTT for gestational diabetes, if at risk | 24–28 usual NHS timing (weeks of pregnancy) |
| Repeat FBC (anaemia check) | around 28 usual NHS timing (weeks of pregnancy) |
| Anaemia threshold (haemoglobin) | below 110 g/L in the first trimester; below 105 g/L later usual NHS timing (weeks of pregnancy) |
All screening is offered, not compulsory. Exact timings vary slightly between NHS trusts and UK nations — your midwife will give you your local schedule.
Booking bloods are taken by your midwife, with your consent, at or soon after your booking appointment. NHS trusts generally aim to take them before 10 weeks.
Full blood count — checks haemoglobin for anaemia, which is common in pregnancy and usually due to low iron.
Blood group and rhesus (D) status, plus a check for red cell antibodies that could affect the baby.
Hepatitis B, HIV and syphilis — infections that can pass to the baby. If one is found, treatment and specialist care greatly reduce that risk.
Sickle cell and thalassaemia — inherited conditions affecting haemoglobin. The test shows whether you carry one of them; if you do, your midwife will explain what further testing is offered.
The combined test pairs a blood sample with the nuchal translucency measurement at the 12-week scan to estimate the chance that the baby has Down's, Edwards' or Patau's syndrome. It gives a chance, not a diagnosis. If it is too late for the combined test, a quadruple blood test between 14 and 20 weeks screens for Down's syndrome. These tests are optional — you can choose some, all or none.
If your blood group is D (rhesus) negative, the NHS can test the baby's blood type from a sample of your blood. If the baby is D negative, there is no risk. If the baby is D positive, you will be offered anti-D injections to stop you developing antibodies that could harm this or a future baby. Anti-D does not work if you already have antibodies; in that case you are offered extra scans and blood tests to monitor the baby.
Around 28 weeks you are offered another full blood count to check for anaemia; in some trusts this sample is also used for diabetes screening or to recheck antibodies.
UK guidelines define anaemia in pregnancy as haemoglobin below 110 g/L in the first trimester and below 105 g/L in the second and third trimesters. If you are anaemic, you will usually be offered iron.
An oral glucose tolerance test (OGTT) at 24–28 weeks is offered if you are at higher risk of gestational diabetes — for example if you are overweight, have had gestational diabetes or a baby weighing 4.5 kg or more before, have a close relative with diabetes, or have a South Asian, Black, African Caribbean or Middle Eastern family background. You fast, give a blood sample, drink a glucose drink and have a second sample two hours later. If you have had gestational diabetes before, you are offered testing earlier, soon after booking.
At antenatal appointments you will also give a urine sample, which is checked for protein among other things. Protein can mean a urine infection or be a sign of pre-eclampsia, which is why it is checked together with your blood pressure.
Checked against:
No need to decode the numbers yourself: take a photo of the report and the app explains “Blood tests in pregnancy (UK)” and the rest in plain words — what is normal and what deserves attention.
App StoreGoogle PlayWeb versionBlood count (anaemia), blood group, rhesus status and antibodies, hepatitis B, HIV, syphilis, and sickle cell and thalassaemia.
At or soon after your booking appointment, ideally before 10 weeks. Infection screening is usually at 8–12 weeks.
A full blood count to check for anaemia; some trusts also recheck antibodies or screen for diabetes. An OGTT at 24–28 weeks is offered if you have risk factors.
In UK guidelines, below 110 g/L in the first trimester and below 105 g/L in the second and third trimesters.
No. All pregnancy screening tests are offered, and you can choose which to have. Your midwife can explain each one.
This material is for general information only. It is not a medical opinion and does not replace a consultation with a doctor. Reference ranges depend on the laboratory and the method — rely on the range printed on your own report. Your doctor makes the final interpretation.
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