Bleeding during pregnancy can be worrying — from light spotting to heavy fresh bleeding. Important: a true menstrual period does not occur during pregnancy. This guide explains the differences, common causes, warning signs and next steps. For detailed background see guidance from India's Ministry of Health and Family Welfare and ICMR, and international resources such as the ACOG FAQ, NICE guideline NG126 (ectopic pregnancy & miscarriage) and patient information from professional colleges.
Why a period is not possible during pregnancy
Menstruation is the shedding of the built-up uterine lining without pregnancy. If pregnancy has occurred, the lining remains to support the embryo. Bleeding during pregnancy therefore has other causes — never a regular menstrual period.
Period vs. pregnancy bleeding – how to tell
Period: heavier, steady flow over 3–7 days, recurring in cycles, often with cramp-like menstrual pain.
Pregnancy bleeding: usually spotty or streaky, light to dark red, lasting hours up to a few days, not cyclical.
Quick check: colour, amount & accompanying signs
- Pale pink or brown, very little: often implantation bleeding or hormonal withdrawal around the expected period date.
- Bright red after sex/examination: typical contact bleeding from the sensitive cervix; usually settles quickly.
- Dark red, heavier, with tissue: a warning sign of possible miscarriage — seek medical assessment.
- Massive bleeding + one-sided pain/dizziness: suspicion of ectopic pregnancy or placental complication — go to the emergency department immediately.
Common causes of bleeding in pregnancy
Implantation bleeding
6–12 days after fertilisation: small vessels break when the blastocyst implants. Very light, pale pink/brown, usually up to 1–2 days. More information: ACOG.
Pseudo-menstruation (hormonal withdrawal bleed)
Short-term hormonal fluctuations can cause a small bleed around the expected period date. Clearly less and shorter than a normal period.
Contact bleeding
During pregnancy the cervix is highly vascular. A vaginal exam or intercourse can irritate small vessels. Bright red, usually stops within a few hours.
Cervical causes, infections & minor injuries
Cervical polyp, ectropion, bacterial vaginosis or yeast infection can cause spotting. Swab and targeted treatment. Info: NHS.
Subchorionic haematoma
Collection of blood between the chorion and uterine wall. Common finding in early pregnancy ultrasound. Management depends on size with follow-up scans.
Ectopic pregnancy (extrauterine)
From about 5–6 weeks' gestation: one-sided severe pain, dizziness, sometimes sudden heavy bleeding. Life-threatening if rupture occurs. Seek immediate assessment. See guideline: NICE NG126.
Miscarriage (pregnancy loss)
Increasing bleeding, cramp-like pain, possibly passage of tissue. Diagnosis by ultrasound and serial hCG. Patient information: RCOG.
Placental complications (2nd/3rd trimester)
Placenta praevia: painless, fresh bright-red bleeding. Placental abruption: usually pain with a hard abdomen. Late bleeding is always a reason to attend hospital. Overview: NHS.
Frequency by trimester
| Trimester | Typical causes | Assessment |
|---|---|---|
| 1st trimester (0–12 weeks' gestation) | Implantation, hormonal withdrawal bleeding, contact bleeding, subchorionic haematoma, ectopic pregnancy, miscarriage | Light bleeding is common; always discuss with a clinician. |
| 2nd trimester (13–27 weeks' gestation) | Less common; assessment focuses on placental location (praevia), cervical length, infections | Fresh bleeding should be evaluated (clinic/hospital). |
| 3rd trimester (28–40 weeks' gestation) | Placenta praevia, placental abruption, vasa praevia, bloody show as sign of labour | Fresh bleeding can be serious — go to hospital immediately, especially with pain or dizziness. |
Diagnostics: what answers what?
- Transvaginal ultrasound: position of gestational sac/embryo, fetal heart activity, placental location, haematomas.
- Serial hCG & progesterone: trends to distinguish a viable from a failing pregnancy.
- Vaginal swab: detect BV/yeast, with targeted therapy where needed.
- Blood group & rhesus factor: For Rh D negative women, anti‑D prophylaxis may be indicated depending on the situation (after bleeding/trauma/procedures — see guidelines).
Diagnostic pathways: NICE NG126. Concise patient information: RCOG and NHS.
Self-care & behaviour until assessment
- Observe: note colour, amount, duration and accompanying symptoms (pain, fever, dizziness).
- Pads instead of tampons/cup: hygienic and allows better assessment of blood loss.
- Rest: avoid vaginal sex and heavy lifting for now; reduce stress.
- Medications: painkillers only after advice; fever and severe pain are warning signs.
Go to hospital immediately – these signs are an emergency
- heavy fresh bleeding or circulatory symptoms (dizziness, fainting, cold sweat)
- one-sided severe abdominal/shoulder pain (suspected ectopic pregnancy)
- bright red bleeding in the 2nd/3rd trimester, even without pain (placenta praevia)
- painful bleeding with a hard abdomen (placental abruption)
- fever or foul-smelling discharge
Conclusion
In pregnancy: no true menstrual period — but bleeding can occur. Light spotting can be harmless; fresh bright-red or heavy bleeding is a warning sign. Observe colour and amount, rest, use pads and have bleeding assessed by a clinician without delay. With pain, dizziness or late pregnancy bleeding: go to hospital immediately.