What public maternity care covers

Screening tests in Ireland are delivered through the maternity unit or hospital where you booked, and most are free as part of public maternity care and the Maternity and Infant Care Scheme. The HSE draws a hard line between screening and diagnosis: a screening test tells you whether you are at low or high risk, and a diagnostic test tells you whether a condition is actually present.

The routine offer is:

Booking visit: a blood sample taken with one needle and tested for a range of conditions, plus a dating scan.
Before 15 weeks: a dating scan. All pregnant women in Ireland are offered one.
18 to 22 weeks: the fetal anatomy scan, also called the anomaly scan.
Around 24 to 28 weeks: gestational diabetes screening, if your unit offers it universally or if you have risk factors.
28 weeks: anti-D injection if you are rhesus negative.

The blood tests

One sample covers everything. You are offered a full blood count for anaemia, which is most often caused by low iron and is treated with supplements and dietary advice, and a test for blood group and rhesus factor.

The rhesus result is the one with consequences. If you are rhesus negative, your body may produce antibodies against the rhesus protein, which can cause anaemia and jaundice in your baby and affect future pregnancies. Anti-D injections prevent this and are offered at 28 weeks, after the birth, and earlier in pregnancy if you have an injury to your abdomen or a bleed. Some hospitals can now determine your baby's rhesus status from your blood, which means anti-D can be skipped where it is not needed.

The same sample is screened for infectious diseases and immunity:

Rubella immunity is checked in every pregnancy. Most people are immune from childhood vaccination. If you are not, you are offered MMR after the birth.
Syphilis, which if untreated can cause miscarriage, stillbirth or symptoms in the baby. Most people with syphilis have no symptoms.
Hepatitis B and HIV.
Chickenpox immunity in some hospitals, especially if you cannot remember having it.
Parvovirus immunity, if you have been in contact with someone who has it.

Additional blood tests for sickle cell disease and thalassaemia are usually offered before 10 weeks, and are more likely to be offered if you or your family come from the Mediterranean, Africa, the Caribbean, India, Pakistan or other parts of Asia.

The scans

The dating scan should be done before 15 weeks. It detects the heartbeat, estimates your due date, measures the baby and identifies a multiple pregnancy. You will need a full bladder for it, because in early pregnancy the womb sits low in the pelvis and a full bladder pushes it up.

The fetal anatomy scan at 18 to 22 weeks checks how the baby is developing, looks for structural problems such as spina bifida and heart defects, shows the position of the placenta and can often show the baby's sex. It will not detect everything. The HSE lists some cases of Down syndrome, some cases of cerebral palsy, and autism among things the scan does not pick up. If a problem is identified you are offered an appointment with a fetal medicine specialist. If growth looks fast or slow you may be offered extra scans, and a scan at 32 to 34 weeks may be offered to rule out a low-lying placenta.

The gap: screening for Down syndrome is not free here

This is the point where Irish maternity care differs sharply from the NHS or from public systems in Australia and New Zealand. The HSE states plainly that non-invasive prenatal screening is not offered as part of free public maternity services. You can choose to have it, and you pay for it.

NIPS — also called NIPT — screens for trisomy 21 (Down syndrome), trisomy 18 (Edwards' syndrome) and trisomy 13 (Patau's syndrome) from a maternal blood sample, alongside an ultrasound. The HSE stresses that the blood test and the scan should be done together for best accuracy. If NIPS is not available in your maternity unit, you can arrange it privately. Costs vary between providers and are not reimbursed.

The practical consequence is that many women in Irish public care reach the 20-week anatomy scan with no chromosomal screening at all, simply because nobody explained that the option existed and had a price attached. Ask about it at your booking visit, not at 18 weeks.

Gestational diabetes screening

An oral glucose tolerance test checks for gestational diabetes. Provision varies by hospital: some maternity hospitals offer the test to every pregnant woman, others only to women with risk factors. If you have risk factors and your hospital screens selectively, make sure they are recorded in your notes. Untreated gestational diabetes has real consequences for you and your baby, and it is easily managed once detected.

If a screening test comes back high risk

A high-risk result leads to a referral for a diagnostic test. These are the only tests that give near-certainty, and they carry a small risk of miscarriage.

Chorionic villus sampling (CVS) takes a sample of placental cells, usually between 11 and 12 weeks and sometimes up to 14 weeks, either through the abdomen or through the cervix depending on where your placenta sits. 1 or 2 in every 200 women who have CVS will miscarry, usually with symptoms starting two to three days afterwards. Between 1 and 2 in every 100 get a false positive caused by placental mosaicism rather than a problem in the baby.
Amniocentesis takes a sample of amniotic fluid through the abdomen, usually after 15 weeks. It is very accurate. 1 in 300 women who have amniocentesis will miscarry. Full results can take two to three weeks.

Both are uncomfortable, and period-like cramps for a few days afterwards are normal. Contact the maternity hospital immediately if you have fluid leaking from the vagina, severe abdominal pain, vaginal bleeding, a general feeling of being unwell, or a temperature over 38°C.

What happens if you decline

Screening is a choice and declining does not affect the rest of your care. The HSE's own framing is that only you can decide what is right for you and your pregnancy, and it publishes a list of questions worth asking: do I need this test, what is it for, what does a high-risk result mean, what should I do if I get one, and what could happen if I do not have the test.

Some people decline chromosomal screening but accept the anatomy scan, which examines structure rather than chromosomes. Some accept a screening test but would not proceed to a diagnostic test regardless of the result, which is a legitimate position and worth saying out loud, because it changes what is useful to do.

Where to get help

The Health Service Executive is the governing authority for maternity screening in Ireland and publishes the current test list on hse.ie. Your midwife, obstetrician or GP is the person to ask about your own pathway, and the repeated GP appointments under the Maternity and Infant Care Scheme give you several natural opportunities to raise it. You can ask for an interpreter if English is not your first language. The HSE Health App shows your maternity appointments, and the free HSE My Pregnancy email series covers each stage of pregnancy.

Screening tests in pregnancy in Ireland