Most women conceive, notice a missing period, and then spend nine months (plus about six months after delivery) without any menstrual flow. Other women, however, experience menstrual or menstrual-like bleeding after a positive pregnancy test. Some types of bleeding are safe and normal, while others signal that there's something wrong with the pregnancy. Any unexplained bleeding (particularly if it's heavy) is worth discussing with a physician.
Chemical Pregnancy
It's rare for a woman to suspect she's pregnant before implantation occurs (typically seven to 10 days after ovulation), but every once in a while, she'll have a sense that something's different, and she might use a home pregnancy test. If the test comes back positive, but she experiences a menstrual period a few days later, she has had what is known as a chemical pregnancy, explain Heidi Murkoff and Sharon Mazel in their book, "What To Expect When You're Expecting." The vast majority of pregnancies (about 70 percent) are chemical, meaning that conception occurs but implantation does not. These are not miscarriages, but are instead fertilized eggs that failed to implant.
Implantation Bleeding
Sometimes, a pregnant woman will have a bit of light bleeding around or slightly before the time of her monthly period. This spotting is the result of a fertilized egg burrowing into the lining of the uterus. Implantation bleeding may be extremely light, or it may be mistaken for a normal menstrual period (particularly for women who menstruate lightly anyway). In the coming weeks, a woman should notice symptoms of pregnancy.
Sex
In "Conception, Pregnancy and Birth," Dr. Miriam Stoppard notes that during pregnancy, the cervix becomes very fragile and vascular. As a result, it's often possible to experience some bleeding that looks like a period after intercourse. This is because the penis rubs against the cervix, causing painless spotting or bleeding. Dr. Stoppard suggests that unless bleeding is very heavy or goes on for more than a few hours, it's not necessary to contact a physician about post-intercourse blood.
Miscarriage
The first trimester of pregnancy is the most vulnerable time for miscarriage, which is the death of and subsequent expulsion of the embryo. This process is accompanied by period-like cramps and bleeding, and signals that the pregnancy is no longer viable. Very early miscarriages may not require any medical intervention, but Dr. Stoppard notes that the more advanced a pregnancy, the more likely it is that a miscarriage will require medical treatment.
References
- "What to Expect When You're Expecting"; Heidi Murkoff and Sharon Mazel; 2008
- "Conception, Pregnancy and Birth"; Miriam Stoppard, M.D.; 2008
