Pregnancy occurs when an egg is fertilized by a sperm, grows inside a woman's uterus (womb), and develops into a baby. In humans, this process takes about 280 days (40 weeks).
The doctor will use certain terms in discussing a woman’s pregnancy. Some of the following definitions are useful:
Intra-uterine pregnancy: A normal pregnancy occurs when a fertilized egg is implanted in the uterus (womb) and an embryo grows.
Embryo: The term used for the developing fertilized egg during the first 12 weeks of pregnancy.
Fetus: The term used for the developing embryo after 12 weeks of gestation.
Beta human chorionic gonadotropin (also called beta-hCG): This hormone is secreted by the placenta and can be measured to determine the presence and progression of the pregnancy. Urine or blood can be tested for its presence, and it is the hormone measured by a home pregnancy test. A positive result means a woman is pregnant; however, this test result can stay positive for several weeks after delivering a baby or after a miscarriage.
Trimester: The length of time of a pregnancy is divided into 3 sections called trimesters (about 3 months each). Each trimester has particular events and developmental markers. For instance, the first trimester builds the foundation of the different organ systems.
Estimated date of delivery (EDD): The delivery date is estimated by counting forward 280 days from the first day of the woman’s last period. It is also called the estimated date of confinement (EDC).
The woman who is pregnant and her doctor will monitor the pregnancy either to prevent certain conditions from developing or to treat those conditions early. These conditions include the following:
High-risk pregnancy: If a woman is considered to be likely to have complications during pregnancy, the pregnancy may be termed high risk. Examples include pregnancies in women with diabetes and those with high blood pressure.
Ectopic pregnancy: This is a pregnancy in which the egg implants somewhere other than the uterus. This can be life threatening. Ectopic pregnancy must be diagnosed early to avoid damage to the fallopian tubes and to prevent serious illness or death. It is also called tubal pregnancy or extra-uterine pregnancy.
Preeclampsia/eclampsia: Preeclampsia causes the blood pressure to rise in the woman who is pregnant, her body to swell, and her nervous reflexes to change. If left untreated, preeclampsia can lead to eclampsia, a serious illness that causes seizures, coma, and even death.
Pregnancy occurs with the fertilization of a woman's egg by a man's sperm. Fertility drugs may improve a woman's odds of achieving pregnancy.
Symptoms of pregnancy include the following:
Nausea, vomiting, or both
Missing a period or having an abnormal period
Breast enlargement, nipples darkening, or breast discharge
Urinating more frequently than usual
Fetal movement (after 20 weeks for new mothers)
When to Seek Medical Care
If a woman suspects that she is pregnant or has a positive home pregnancy test, she should make an appointment with a health care provider, which could be a doctor, an obstetrician (women's health specialist), a midwife, or a nurse practitioner. Early care (prenatal care) is essential for a healthy pregnancy.
A woman who is pregnant should call her health care provider if any of the following conditions develop:
Abdominal or vaginal pain
Bright red vaginal bleeding
Vomiting more than 3 times a day or vomiting blood
Severely elevated blood pressure (above 140/90)
Sudden and rapid weight gain
Severe headache or changes in vision
Severe leg or chest pain
Seek care in a hospital's emergency department if pregnant and experiencing any of these conditions:
Vaginal bleeding through more than 1 pad per hour
Having severe pain in the abdomen or shoulder or the sensation of being about to pass out
Passing pink, gray, or white material from the vagina that does not look like a blood clot (The woman who is pregnant should take the material to the hospital.)
Having a bloody discharge or gush of water from the vagina late in pregnancy (The woman who is pregnant may be going into labor.)
Having a seizure but without a history of epilepsy (This may indicate eclampsia, a complication of pregnancy.)
Having an injury, such as a fall, a blow to the stomach or pelvis, or a car accident
Lower abdominal pain late in pregnancy may be labor pains, which are contractions of the uterus. The woman may try to drink a quart of water, lie on her side, and see if the symptoms resolve over two hours. If the symptoms do not resolve, she should see a doctor.
Questions to Ask the Doctor
Am I at risk for genetic diseases?
How much weight should I gain?
How should I alter my diet (especially if a vegetarian or a vegan)?
What tests should I have and when should I schedule them?
Am I a high-risk patient?
What is my risk for cesarean birth?
Exams and Tests
Several tests may be conducted while a woman is pregnant.
Pregnancy tests: The woman’s urine or blood may be tested.
If a woman’s period is late, she may use a home pregnancy test. This is a urine test kit that can be purchased at a pharmacy or grocery store. The test can indicate whether a woman is pregnant. This type of test is known as a qualitative test. It can only test yes or no for the pregnancy hormone, beta-hCG. If a doctor is considering prescribing a medication that might not be appropriate to take during pregnancy, one of these simple tests may be performed in the office to determine if a woman is pregnant or to make sure she is not pregnant. If the test is performed very early in a pregnancy, the hormone level may still be negative. Some home pregnancy tests might not show positive results until 7-10 days after a missed period.
More sophisticated tests are called quantitative because they measure hCG levels in the blood. This type of testing is completed by drawing blood for testing at a hospital or doctor’s office. These levels indicate how far along a woman is in her pregnancy. If levels of hCG do not rise as she progresses in her pregnancy, it could indicate something is wrong (such as an ectopic pregnancy with low levels) or surprising (high levels may indicate twins).
Ultrasound: A doctor may use sound waves to examine the internal structures such as the uterus, ovaries, and the embryo or fetus.
Transabdominal ultrasound: A jelly is put on the abdomen, and a hand-held sound-wave wand is moved around to look at the internal structures. The woman’s bladder must be full to help transmit the sound waves, so she may be asked to drink 2-3 glasses of water starting an hour before the test. This method works best later in pregnancy when the fetus is well developed. The doctor may have a scan performed during the first trimester to make sure the pregnancy is in the uterus and not outside it (ectopic pregnancy) and to assess the woman’s risk for having a miscarriage. The scan can also tell if more than one fetus is developing. During the remainder of the pregnancy, scans may be used to look for problems, assess the age and development of the fetus, check out its position, and, by 17 weeks, determine the sex. There is no risk to the woman or her developing fetus with ultrasound, and it is not uncomfortable. Ultrasounds help doctors establish the due date. Due dates can now be predicted within 2-4 days.
Endovaginal or transvaginal ultrasound: A long, thin, sound-wave wand is covered with a condom and put inside the vagina. This type of ultrasound is usually performed early in pregnancy to make sure that the embryo or fetus is inside the uterus where it belongs. This type of ultrasound also gives more detail, for instance, about the structure of the woman’s cervix and the early embryonic anatomy.
Blood type, Rh status, and antibody test
Sickle cell screening if of African American heritage
Syphilis tests, HIV test, and tests for hepatitis B
Alpha fetoprotein tests
Gonorrhea culture (GC) and chlamydia culture
Group B streptococcal test by 35 weeks
Test for bacterial vaginosis (BV), an infection in the vagina, if the woman has vaginal discharge
Normal pregnancy is not an illness and needs no treatment other than standard prenatal care. If a woman’s pregnancy is difficult or complicated, her treatment can vary from simple bedrest to amniocentesis, which is removal, for testing, of a small amount of amniotic fluid from the amniotic sac surrounding the fetus. Fetal monitoring with a machine, an ultrasound physical assessment, or a stay in the hospital for testing or medication may also be part of the treatment.
Flu shots are recommended for women who are pregnant. (See Flu in Adults for more information.)
Self-Care at Home
Eat small, frequent meals throughout the pregnancy. Eat a common-sense balanced diet. Expect to gain between 25-35 pounds.
Do not discontinue prescribed medications without consulting a doctor, but also consult with a doctor before taking any nonprescription medications.
Ginger capsules (available as an over-the-counter option) may help with nausea in pregnancy, sometimes called morning sickness. Talk with a doctor about other options.
Do not smoke, drink alcohol, or use street drugs.
Continue to exercise with normal routines unless the doctor advises otherwise; be sure to get adequate water intake for exercise.
Sexual intercourse is safe and natural during an uncomplicated pregnancy.
Electronic fetal monitoring: Sometimes late in pregnancy, a woman who is pregnant may be placed on a fetal monitor to verify the health of the fetus or to see if the woman is in early labor.
Because so many medicines are not safe to take during pregnancy, it is extremely important that a woman take only those that have been approved by her doctor. If anyone tries to prescribe a new medicine, the woman should explain that she is pregnant and ask if the drug is safe to take. The US Food and Drug Administration lists 5 categories of labeling for drug use in pregnancy. A doctor or pharmacist can provide advice on the safety level (indicated by category) of medications before a woman who is pregnant takes anything. Doctors will often use category B and C medications (see the following list) if a woman’s medical needs warrant the use of those medications. Not all conditions have category A medications available for treatment.
Category A - Safety established using human studies
Category B - Presumed safety based upon animal studies
Category C - Uncertain safety with animal studies showing an adverse effect
Category D - Unsafe with evidence of risk that may, in certain clinical circumstances, be justifiable
Category X - Highly unsafe with risk or use outweighing any possible benefit
For the first few months of pregnancy, monthly doctor's visits are standard. After that, visits are biweekly until the last month of pregnancy when doctor's visits are weekly. Usually, blood testing and anemia checks are performed at the first doctor's visit and at the 16- and 28-week visits.
The doctor will probably provide the woman who is pregnant some information to read about pregnancy. She should ask questions if she needs help understanding the information or what is happening during the pregnancy.
Contraception is the term used for preventing pregnancy. There are many ways to prevent pregnancy, but none of them is 100% effective except not having sexual relations (abstinence). The following are current methods of contraception:
Sterilization - Male (vasectomy) or female (tubal ligation or tubal implant)
Hormonal contraceptives - Birth control pills, birth control patches, birth control vaginal ring
Intra-uterine device (IUD) or intra-uterine system (Mirena)
Coitus interruptus - Withdrawal by the male before climax
Rhythm method - Not having sex during the time when is woman is most likely to be fertile
Many events determine the outcome of a pregnancy.
Maternal weight gain: The amount of weight a woman gains when pregnant can be important in predicting a normal pregnancy.
Too much weight gain puts the woman who is pregnant at risk for diabetes and hypertension, and it may increase the chance for needing a cesarean birth.
Too little weight gain puts the baby at risk for growth retardation and the mother at risk for anemia, nutritional deficiencies, and osteoporosis.
Nausea and vomiting: Even if the woman who is pregnant experiences what seems like an abnormal amount of nausea and vomiting (morning sickness), it probably will not affect the baby's health, particularly if the woman is still gaining weight at the expected rate.
Maternal diabetes (types 1 and 2): If the woman who is pregnant has diabetes or develops diabetes during pregnancy, it can cause early labor, birth defects, and very large babies.
Low or high red blood cell counts: The risk of having a baby prematurely is increased if the woman’s blood count is low (anemia). Low blood counts also put her at risk of needing a transfusion after delivery. If the woman’s blood count is too high (polycythemia), her baby may be smaller than expected.
Maternal obesity: If a woman who is pregnant is obese and has diabetes, her baby is 3 times more likely to have a birth defect. If she is obese but does not have diabetes, the risk of birth defects is not increased.
Maternal age: If the woman who is pregnant is older than 35 years, her baby has a higher risk of birth defects and complications. The focus of genetic screening is to enable the woman to understand any problems her fetus or infant may have. There is a 2-3% rate of major birth defects in this population.
For More Information
MedlinePlus, Pregnancy test
MedlinePlus, Pregnancy ultrasound
American Association for Clinical Chemistry, Lab Tests Online, hCG test
Women's Health Practice, Childbirth
Women's Health Practice, Birth Plan