Formulas & normal valuesFree in the app
Normal values in pregnancy
Physiology changes the reference ranges.
Source: BSH · Abbassi-Ghanavati 2009 · NICEBlood
| Hb | ≥110 g/L (1st trim), ≥105 (2nd/3rd), ≥100 postpartum. |
|---|---|
| Platelets | ~146–429 × 10⁹/L in 3rd trimester. |
| WCC | Up to ~15 × 10⁹/L; higher in labour. |
| Creatinine | 35–80 µmol/L — ≥90 is abnormal (NICE). |
| Fibrinogen | 3.7–6.2 g/L at term — <2 g/L in PPH is critical. |
| ALP | Up to 2–4× normal (placental). |
| ALT | Unchanged — rise is abnormal. |
| Bile acids | ≥19 µmol/L = cholestasis. |
| TSH target | <2.5 (1st trim), <3.0 later on levothyroxine. |
Physiology
| Heart rate | Up 15–20 bpm. |
|---|---|
| Cardiac output | Up ~40%. |
| Plasma volume | Up ~50% (red cells +25–30%). |
| BP | Lowest in 2nd trimester. |
| Breathing | Minute ventilation up ~50%; PaCO2 lower (~4 kPa). |
| GFR | Up ~50%. |
A summary for trained clinicians. Always check the full guideline, the patient in front of you and your hospital's protocol. Spotted an error? Tell us.