Pregnancy blood tests
What is tested and how results are interpreted in context.
Open informationWeeks 1–13+6
First trimester: confirmation, dating and screening
This is a rapidly changing stage. Follow-up combines maternal health, pregnancy location and viability, dating and estimation of selected risks.
- Obstetric consultation
- Advanced ultrasound
- Laboratory and screening
- Late-pregnancy monitoring
- Nutrition
Complementary follow-upAskabide + Osakidetza · birth at the reference hospital
Consultation and maternal checks
- Medical and obstetric history.
- Blood pressure, weight and clinical review.
- Medication, habits and supplements.
- Planning blood tests and ultrasound.
- Identification of risk factors and referral needs.
Initial laboratory tests
These may include full blood count, blood group and Rh, antibody screen, glucose, urine, serology and additional tests according to history and protocol. The same fixed list does not apply to every patient.
Rh negative
What it means and which checks may apply.
Open informationUltrasound and screening
The 11–13+6 week scan supports dating, fetal number, early anatomy and markers used in screening programmes. Screening estimates risk; it does not by itself establish a diagnosis.
First-trimester ultrasound
Dating, nuchal translucency and early assessment.
Open information
NI/+ from week 10
Expanded maternal blood screening.
Open information
MaiRa · preeclampsia
Risk-based screening and prevention.
Open informationWhat may change the plan
- Bleeding or pain.
- Hyperemesis or inability to maintain hydration.
- Hypertension or maternal disease.
- Multiple pregnancy.
- Ultrasound or laboratory findings.
- Relevant obstetric history.
Clinical sources
General information only. It does not replace an individual medical assessment or recommendation.
Osakidetza · Información durante el embarazoOsakidetza · Cribado prenatal cromosómicoMinisterio de Sanidad · Cribado prenatal de preeclampsia
Reviewed 19 August 2026