Pre-Pregnancy Blood Tests UK: What to Ask Your GP For

Pre-pregnancy blood tests UK guidance can feel like a postcode lottery, and most women I see in clinic ask the same thing: what should I actually have done before I start TTC? The NHS does not run a standard "pre-pregnancy panel", which leaves a lot of women guessing. This post lays out what your GP will offer, what's worth asking for, and where a private panel earns its keep.

What the NHS Routinely Offers Pre-Conception

NHS pre-conception bloods are not a single bundled service. Outside of antenatal booking (which happens after you're already pregnant), there is no standard panel that every woman planning a baby is offered.

What your GP will do is run relevant tests based on your history. Thyroid function if you have symptoms or family history. Ferritin if you've had heavy periods. Vitamin D if you're symptomatic or in a high-risk group. Blood group and rhesus status if you don't already know it. Cervical screening will be reviewed and updated if due.

This isn't a failing of the NHS. It's a triage philosophy: test where there is a clinical question to answer. For a fuller picture of everything that belongs in your pre-conception window, see the full pre-conception health checklist.

If you want the comparison perspective, the pre-conception advice page on NHS Scotland lays out a similar triage approach.

Bloods Worth Asking Your GP About

A practical list of what blood tests should I have before pregnancy in the UK, and what to request explicitly:

• Full blood count (FBC) to check for anaemia
• Ferritin to assess iron stores, which is often low in menstruating women even when FBC looks fine
• Vitamin D (25-hydroxy) because ^[src]the NHS recommends 10 micrograms daily in pregnancy and many women start the journey deficient
• Blood group and rhesus status if unknown, because rhesus negative status changes antenatal care
• HbA1c if you have any diabetes risk factors (BMI over 30, PCOS, family history, prior GDM, certain ethnicities)
• TSH (covered in the next section)

Which pre-pregnancy bloods does the NHS cover? FBC, ferritin (if there's a reason), TSH (if there's a reason), blood group (often), and HbA1c (if risk factors apply). The phrase "if there's a reason" is doing a lot of work, which is why being explicit at the appointment helps. Also confirm when to start folic acid before TTC, because that conversation belongs in the same visit.

Thyroid Function, Why It Matters

Thyroid TSH pre-conception screening is one of the highest-yield tests for women planning pregnancy.

^[src]NICE NG145 covers thyroid disease assessment and management, including the lower TSH targets recommended in early pregnancy. Subclinical hypothyroidism (raised TSH with normal free T4) is associated with reduced fertility and higher miscarriage rates in some studies, and is straightforward to treat.

A common scenario: a woman has a TSH of 3.5 mIU/L, which her GP reports as "in range" for the general adult population. In early pregnancy, the target is closer to under 2.5 mIU/L. That gap matters, and the time to discuss it is before conception, not at the booking visit.

Rubella, Chickenpox, and Other Immunity Checks

Rubella immunity test pregnancy guidance has shifted over the last decade as MMR vaccination coverage has fluctuated. If you're not sure whether you're immune, ask.

• Rubella: confirm immunity pre-pregnancy. If you're not immune, MMR can be given before conception, with a recommendation to avoid pregnancy for 4 weeks after.
• Varicella (chickenpox): confirm prior infection or vaccination. Varicella in pregnancy can be serious for both mother and baby.
• Hepatitis B: status check is appropriate for women at risk (occupational, household exposure, certain travel history).
• HIV and syphilis: routinely offered at antenatal booking, but many women prefer to know their status pre-conception. Your GP can arrange these.

Updating immunity before conception is simpler than catching up during pregnancy, where live vaccines are off the table.

PCOS, Thyroid Disease, and Recurrent Miscarriage, Extra Tests

Certain histories justify a wider workup before TTC.

PCOS or suspected PCOS: ^[src]the 2023 International PCOS Guideline recommends an OGTT (or fasting glucose plus HbA1c) before conception or before starting fertility treatment. ^[src]NICE NG3 also addresses pre-pregnancy diabetes screening. For the wider PCOS-to-pregnancy picture, see PCOS and gestational diabetes risk.

Recurrent miscarriage (2 or more): antiphospholipid syndrome screen (lupus anticoagulant, anticardiolipin, anti-beta-2-glycoprotein), thyroid antibodies, karyotype testing for both partners as indicated, and a structural review of the uterus.

Thyroid disease: TSH, free T4, and TPO antibodies if not previously checked. Optimisation before conception is the goal.

Suspected endometriosis or pelvic pathology: bloods are usually a small part; pelvic ultrasound and specialist review are the main investigations.

Carrier and Genetic Screening, the Quiet Gap

The NHS offers sickle cell and thalassaemia screening as part of antenatal booking, and can offer pre-conception carrier screening on request, particularly where ethnicity or family history raises the case.

Expanded carrier screening (cystic fibrosis, spinal muscular atrophy, Fragile X, and broader panels) is not standard NHS pre-conception care. It's available privately, with panels starting around £200 to £500 depending on breadth. ACOG in the US recommends offering carrier screening to all women planning pregnancy; the NHS lags here.

The case for earlier screening strengthens with consanguinity, known family carrier status, or membership in a population with higher prevalence of specific recessive conditions.

NHS vs Private, How to Decide

When NHS investigation is enough: regular cycles, no chronic conditions, no concerning family history, age under 35, no recurrent loss.

When private bloods add value: PCOS or suspected PCOS, thyroid disease or borderline TSH, age 35 or older, prior pregnancy loss, family history of inherited conditions, or simply a preference for a structured pre-conception panel done in one visit.

A private pre-conception panel in the UK typically runs £200 to £600 depending on breadth (FBC, ferritin, vitamin D, TSH, free T4, HbA1c, rubella, varicella, sometimes AMH). Add carrier screening on top if relevant.

If you or your partner is comparing systems, the equivalent guide for the US covers the ACOG bundle and insurance reality.

What This Means for You

Pre-pregnancy blood tests UK aren't a one-size-fits-all panel. The NHS triages by history, private clinics bundle by default, and the right answer depends on what's in your medical chart. A focused GP visit and a short list of explicit asks usually closes most of the gap.