Understanding Antenatal Screening Choices: What's Offered and Why You Can Decline

What antenatal screening actually means

The word 'screening' can sound clinical, but it simply means being offered a test that gives you information, rather than a test that's compulsory or that everyone must have for medical reasons. Screening in pregnancy is designed to give you and your midwife a clearer picture, whether that's about your blood group, your baby's development, or the chance of certain conditions.

It's worth separating screening from diagnosis in your own mind. Screening tests estimate a chance or likelihood; they don't give a yes or no answer on their own. That distinction matters because it shapes how much weight you might want to put on any result, and whether you'd want further tests afterwards. None of this article interprets results or thresholds; that conversation belongs with your midwife or a specialist, who can talk through what any particular result would mean for you.

What you'll typically be offered, and when

Antenatal screening is woven through the routine appointment schedule rather than delivered all at once. At your first midwife appointment, usually between 8 and 12 weeks, you'll be given information about the screening tests on offer, along with a blood test to check things like your blood group. This is also your first real chance to ask questions before anything is booked in.

Later scans and blood tests each carry their own screening options. The dating scan around 11 to 14 weeks can include screening for certain chromosomal conditions. The scan at 18 to 21 weeks checks your baby's development. If your circumstances suggest a higher chance of gestational diabetes, testing for this is usually offered between 24 and 28 weeks, alongside a further blood test around the same time to check things like iron levels.

• Booking appointment (8 to 12 weeks): information on screening options plus initial blood tests
• 11 to 14 week scan: dating scan, with optional screening for certain conditions
• 18 to 21 week scan: checks on your baby's development
• 24 to 28 weeks: gestational diabetes testing offered where relevant, plus further blood tests

Why it's framed as a choice, not a requirement

National guidance on antenatal care, including NICE's guideline for professionals, is built around information and support rather than instruction. It's designed to help your midwife or doctor offer consistent, evidence-based care, but it doesn't override your own preferences or the decisions that are right for your circumstances. In practice, that means every screening test should come with an explanation of what it involves, what it can and can't tell you, and what your options are afterwards, before you're asked to decide.

This is sometimes called informed choice, and it applies just as much to declining as to accepting. Saying no to a particular test isn't unusual, and it doesn't need to come with a lengthy justification. You're allowed to ask for more time, ask for the information in writing, or come back to a decision at a later appointment if you're not ready.

Questions that can help you decide

If you're unsure whether a particular screening test is right for you, it often helps to ask a few practical questions before you commit either way. Your midwife is there to talk this through, not to steer you towards one answer, and there's no pressure to decide on the spot.

• What exactly does this test look for, and what does it involve for me physically?
• What would a result actually tell me, and what wouldn't it tell me?
• What happens next if the result suggests a higher chance of something?
• Is there a time limit on when I need to decide?
• Can I change my mind later if I want to add or skip a test?
• Where can I read more about this in my own time before deciding?

If you decide to decline a test

Choosing not to have a particular screening test doesn't change the rest of your antenatal care. Your appointments, scans and general health checks continue as planned, and you can revisit the conversation at a later appointment if you change your mind, within whatever timeframe applies to that particular test. Midwives are used to supporting a range of decisions and shouldn't need you to explain your reasoning in detail.

If declining a test is tied to a specific worry, such as a past experience, a health condition, or something you've read, it's worth mentioning that to your midwife, GP or health visitor directly. They're best placed to talk it through with you properly; this article can only offer a general framework for thinking about choice, not a substitute for that conversation.

Where to go for more support

Your midwife remains the first point of contact for any screening decision, and you can raise questions at any appointment, not just the one where a test is offered. If something feels urgent, maternity triage is there for concerns that can't wait until your next scheduled visit.

For more general reading on pregnancy care and what to expect at different stages, our journal at /blog has related guides that sit alongside this one, covering topics like booking appointments and keeping your maternity notes organised. They're written in the same spirit: practical context to help you ask better questions, never a replacement for advice from the people caring for you directly.