The first sign of pregnancy is a missed menstrual period.
Swollen breasts and nausea with occasional vomiting may also be present. The swelling is caused by hormone changes similar to those a woman may have before her periods. The nausea and vomiting may be caused by hormonal changes produced by the cells of the placenta about 10 days after fertilization.
A woman who is pregnant may feel tired. Some women notice bloating of the abdomen early in a pregnancy.
Causes and Risk Factors
Pregnancy is caused when a sperm fertilizes an egg. It is a potential for sexually active women of childbearing age.
Certain factors may make the pregnancy high risk because they present risks to the health of the mother and baby and to having a normal pregnancy and delivery. These include:
- Preexisting health conditions that make a pregnancy more complex or risky
- Conditions that develop because of the new demands that a pregnancy makes on a woman's body, such as gestational diabetes
- The nature of the mother's body, including height, weight, age or abnormalities in her uterus or pelvis
- Abnormalities in the developing baby or its position inside its mother's body
- A family history of twins, difficult pregnancies or genetic defects
- A personal history of stillbirths, difficult pregnancies, babies with a genetic disorder or birth defect
- Exposure to drugs, viruses or substances such as herpes simplex, viral hepatitis, mumps, rubella, varicella, syphilis, alcohol, cigarettes, lithium, streptomycin, tetracycline, thalidomide and warfarin.
Smoking and alcohol are two serious risk factors to a healthy pregnancy and delivery of a healthy baby. Drug addiction or substance abuse during pregnancy also represents serious risks to the health of the mother and baby.
All substances that a mother eats, drinks or breathes circulate through the baby's blood system as well as her own.
Ideally a woman should seek medical care before she becomes pregnant so that a doctor can:
- Screen for disease
- Advise her about the use of tobacco, drugs, alcohol or other substances
- Check for physical conditions that may affect getting pregnant or having a healthy pregnancy and delivery
- Educate her about maintaining the best health before conception and during pregnancy using diet, exercise and spacing of pregnancies
- Inform her about the risks of exposure to cat litter (which can lead to toxoplasmosis), hot tubs, rubella, secondhand smoke and paint fumes