Bleeding in pregnancy

This is the triage/differential page for bleeding in pregnancy. For the detailed work-up and management of the two main early-pregnancy causes, see Miscarriage and Ectopic pregnancy (both rewritten against RANZCOG C-Gyn 38, 2025).

Causes: idiopathic, iatrogenic (invasive screening tests), infective, miscarriage, dysfunctional uterine bleeding, subchorionic haematoma, placental failure.

Most causes can’t be prevented (infection aside) and can only be monitored — it is a major source of stress for the mother and partner, so counsel sensitively.

Significant bleeding (unstable, or large clots/heavy flow) → send to emergency. Stable patients with lesser bleeding → investigate for cause. Treatment centres on fluid status, Hb, and anti-D requirement.

Anti-D for Rh(D)-negative patients

Arrange an ABO/Rh D type and antibody screen no later than 10 weeks’ gestation, and give written and verbal information about Rh status and Rh(D) immunisation. If Rh(D)-positive, no further action is needed. If Rh(D)-negative with no preformed anti-D antibodies, assess for sensitising events and plan routine prophylaxis.

Obtain informed consent before administration.

RHD NIPT in practice: only a limited set of pathology providers offer it locally (Douglas Hanly Moir among them), and some charge above the MBS item — roughly $50 out of pocket. Check with the provider before ordering, and collect from 12 weeks, as close to 12 weeks as practical so fewer women need prophylaxis for sensitising events.

Routine antenatal prophylaxis

Give Rh D immunoglobulin 625 IU at 28 and 34 weeks, unless NIPT for fetal RHD has predicted the fetus is Rh D negative. A single 1500 IU dose is not currently recommended in Australia. Arrange the antibody screen 1–7 days before the 28-week dose, to confirm antibodies have not developed since the booking bloods. No repeat titre is needed at 34 weeks if immunoglobulin was given at 28 weeks — it will be positive. Clinical discretion allows a dose within two weeks either side of 28 and 34 weeks, but giving the second dose before 34 weeks risks inadequate cover at birth if the pregnancy runs past the due date.

Rh(D)-negative women should be retested at 28 weeks unless NIPT has shown an Rh D negative fetus. Take the specimen before giving the immunoglobulin — but the immunoglobulin can be given before the result is back.

Sensitising events in the first 12 weeks — 250 IU

Sensitising events in the first 12 weeks are miscarriage, termination of pregnancy after 10 weeks, ectopic pregnancy, molar pregnancy and chorionic villus sampling. Give Rh D immunoglobulin 250 IU after any of these to a woman with no preformed anti-D antibodies.

• Termination before 10 weeks: insufficient evidence for routine anti-D.
• Uterine bleeding with an ongoing pregnancy in the first 12 weeks: insufficient evidence for routine anti-D. Consider it where the bleeding is repeated, heavy, or associated with abdominal pain or significant pelvic trauma.
• Uncertain gestational age: consider anti-D, and consider ultrasound to date the pregnancy.
• Repeated events: no evidence to guide practice — seek specialist obstetric advice. For ongoing uterine bleeding alone, a repeat dose (250 IU under 12 weeks, 625 IU after) may be appropriate at a 6-week interval.

Sensitising events beyond 12 weeks — 625 IU

A dose of 625 IU should be offered to every Rh(D)-negative woman with no preformed anti-D antibodies, unless NIPT for fetal RHD has predicted an Rh D negative fetus, for these indications after 12⁺⁶ weeks:

• Genetic studies — chorionic villus sampling, amniocentesis, cordocentesis
• Abdominal trauma considered sufficient to cause fetomaternal haemorrhage, even if FMH testing is negative
• Each occasion of revealed or concealed antepartum haemorrhage — consider concealed APH where there is unexplained uterine pain
• External cephalic version, whether successful or only attempted
• Miscarriage or termination of pregnancy at this later gestation

For ongoing uterine bleeding alone beyond 12 weeks, a further 625 IU may be appropriate at 6-weekly intervals.

Fetomaternal haemorrhage quantitation

After 20 weeks, assess the magnitude of FMH and give further doses if required. Take the maternal sample before administering the immunoglobulin, but never delay the immunoglobulin pending the result. Between 13 and 20 weeks, assess FMH at clinical discretion.

The assay must be able to quantify ≥6 mL of fetal red cells (12 mL whole blood); flow cytometry is the method of choice. Where FMH exceeds the dose already given, add 100 IU per mL of fetal red cells beyond 6 mL.

Giving it

Intramuscular only — deltoid or anterolateral thigh, not the buttock. Do not give it subcutaneously, and do not give it intravenously (anaphylaxis risk): draw back gently before injecting to confirm the needle is not in a vessel. If her BMI is over 30, choose a needle long enough to reach muscle.

A dose given for a sensitising event does not replace routine prophylaxis, and vice versa — if both are indicated, give both.

For consent, cover that it is a human plasma product pooled from screened Australian donors (screened for hepatitis B, hepatitis C, HIV and parvovirus B19), produced by CSL and distributed by Australian Red Cross Lifeblood; that side effects are injection-site pain and, rarely, allergy; and that she may decline.

Timing and postnatal dose

Give Rh D immunoglobulin as soon as practical within 72 hours of the sensitising event. If that window is missed, give it up to 10 days from the event — efficacy is lower.

Postnatally, give 625 IU to every Rh(D)-negative woman with no preformed anti-D whose baby is predicted or shown to be Rh D positive (NIPT for fetal RHD, cord blood, or neonatal Rh D typing). Do cord or neonatal typing regardless of the NIPT result, but don’t let it delay the dose where NIPT has already shown an RHD-positive fetus.

Access: if <20 weeks, refer to an ED at a hospital with a maternity unit or an Early Pregnancy Advisory Service if one is available; if >20 weeks, refer to the local birth suite or ED.

Advice: for a positive antibody screen with no recent immunoglobulin, or any uncertainty, phone the obstetric registrar or haematology service at the local hospital — John Hunter Hospital (02) 4921 3000 if there is no local service. NSW Blood Service on 1300 478 348 has an on-call haematology registrar with consultant backup. Seek obstetric advice for repeated first-trimester sensitising events; a repeat dose may be appropriate after a 6-week interval.

Source (local): RhD Immunoglobulin (Anti-D) Prophylaxis in Pregnancy, Community HealthPathways Hunter New England, last updated 10 June 2026 (registry: hne-healthpathways-rhd-immunoglobulin-prophylaxis; verified 2026-08-31). RHD NIPT provider and cost, the pre-dose antibody screen window, administration technique and local escalation contacts come from this pathway.

Anaemia in pregnancy

Common, as blood volume expansion can outpace red cell mass. May cause pallor, lethargy, fatigue. Check FBC and iron studies at booking, at 28 weeks and again at 36 weeks.

An iron study is the first-line investigation and includes serum iron, ferritin, transferrin and transferrin saturation. Ferritin is the most sensitive component, but it is also an acute-phase protein, so inflammation can falsely normalise or raise it — uncommon in pregnancy, but worth remembering.

Hb 80–100, MCV <80: add ferritin and start oral iron. Therapeutic Guidelines suggests ferrous sulfate 325–650 mg daily (105–210 mg elemental iron). Review at follow-up — if there is no response and Hb is falling, check adherence before considering parenteral iron.

Hb <80, MCV <80: repeat FBC with ferritin and Hb electrophoresis; consider occult iron loss or parasitic disease. If asymptomatic, start iron/vitamin C and review response at 10 days. If symptomatic or not responding, seek O&G advice.

Parenteral iron is for failed oral therapy or where rapid replacement is needed. Avoid intramuscular iron polymaltose — the injections are painful and can permanently stain the skin. Ferric carboxymaltose is the preferred ambulatory formulation, delivering up to 1 g in 15 minutes.

Urgent referral if the blood film shows haematological disease (e.g. leukaemia, myeloma), thrombocytopenia/neutropenia, or signs of haemolysis. Chronic anaemia with Hb <90 g/L, or a persistently low MCV <80, also warrants specialist input.