What would cause spotting in a woman that is 4 weeks pregnant?

There are several reasons why a woman may experience spotting during the fourth week of pregnancy.

Implantation bleeding: This is the most common cause of spotting in early pregnancy. It occurs when the fertilised egg implants in the lining of the uterus. Implantation bleeding usually happens around 10-14 days after ovulation but can occur anytime between 6-12 days after ovulation. Implantation bleeding is usually light and lasts for a few days.

Hormonal changes: Changes in hormone levels during pregnancy can cause the cervix to become more sensitive and prone to bleeding. This can lead to spotting after intercourse or a pelvic exam.

Other causes: Spotting in early pregnancy can also be caused by other factors, such as:

* An ectopic pregnancy (a pregnancy that develops outside the uterus)

* A miscarriage (the loss of a pregnancy before 20 weeks)

* A uterine infection

* Placental abruption (the separation of the placenta from the uterus)

* Subchorionic haemorrhage (bleeding between the placenta and the uterine wall)