Prenatal Care

September 23, 2011

A pregnancy is an exciting and wonderful event in a woman’s life, one which incorporates remarkable physical changes, intense emotions, and growth in important relationships. About 50% of pregnancies are unplanned, which may have consequences to the physical health of the mother and fetus, as well as emotional turmoil. Planning and preparing for a pregnancy will often improve the outcome and is the subject of the entry Preconception care.


One of the most important steps a woman can take when she either suspects a pregnancy or notes a positive home pregnancy test is to establish an early appointment with the obstetric provider. In the United States, there are both physician and nonphysician health care professionals who provide pregnancy care through the delivery of the infant. The physician specialties include obstetricians and some family physicians. Nonphysician professionals include two kinds of midwives: the certified nurse midwife and the lay midwife. The availability of each of these four types of pregnancy care providers varies by region in the United States.

An early prenatal appointment is essential to establish an accurate “due date,” or what the physician calls an “EDC” (estimated date of confinement). A woman should try to make her first prenatal appointment within 2-3 weeks of missing her period or noting a positive home pregnancy test. Any bleeding, cramping, or severe abdominal pain warrants an urgent physician appointment, either with the primary care physician or seeking emergency department services if needed.

Perhaps the most accurate way to settle on the EDC is by a woman’s first day of her last menstrual period (called the “LMP”). A woman should try to keep an accurate record of the first day of the onset of her monthly period for several months prior to a pregnancy. She should also note any additional spotting or abnormalities of her menstrual flow. If a woman has irregular menstrual cycles, or had recently ended the use of oral contraceptive pills to get pregnant, then the obstetric provider will generally order an early (first trimester) ultrasound to establish an accurate EDC.

The first prenatal visit will include a comprehensive review of the medical and family history, a physical examination, and routine laboratory work. The newly pregnant woman should come to this appointment with a well-organized list of her past medical problems, medication allergies, prior surgeries, and family medical history. Additionally, any family history of genetic disorders or mental retardation should be known. The woman should clarify if she has either had chicken pox or received the chicken pox (varicella) vaccine. The woman should have a list of all her current prescription, nonprescription, and herbal medications. The physical examination will include a pelvic exam with updating, the Pap smear, and the obtaining of cultures to exclude infections that may affect the pregnancy. Routine blood and urine testing will establish the woman’s blood type and Rh status, complete blood count (indirectly assessing iron levels), and tests for prior evidence of immunity to rubella (German measles), hepatitis B, and HIV. This first prenatal visit is an excellent time to ask any questions about the pregnancy, upcoming tests, and to clarify any “advice” received from well-meaning friends and relatives.

Common issues that pregnant women face include work concerns, travel advice, exercise, nutrition, and sexual intimacy:

  1. Work concerns. Most occupational activities are safe to continue during a pregnant. The obstetric provider should be aware of the nature of the pregnant woman’s work, and offer advice if the workplace includes exposure to potentially toxic chemicals and extremes in temperature and physical activity.
  2. Travel advice. Automobile and air travel are safe for the majority of the pregnancy. Most major airlines restrict air travel during the last few weeks of pregnancy, and generally the pregnant woman will want to be close to her home and obstetric provider anyway. Whether by car or air, the pregnant woman should stretch every 1-2 hr to minimize any risks to lower leg swelling and potential blood clots. Seat belts should be worn throughout the pregnancy, with the shoulder belt worn as usual and the lap belt fastened low over the hips.
  3. Exercise. In general, overall physical conditioning provides benefits for both the mother and baby. In addition to the sense of well-being, mothers-to-be who are physically fit, benefit from improved sleep patterns and bowel habits. Women are encouraged to maintain their prepregnancy level of fitness, and not try to significantly increase their workouts once pregnant. The obstetric provider will provide advice on which forms of exercise are safest and most effective, as well as maximum heart rate limitations for the pregnant state.
  4. Nutrition. A diet that is adequate in calories and balanced in nutrients is an important component of healthy pregnancy. There are many accurate resources to access complete pregnancy-related nutritional information (some listed under Suggested Reading at the end of this entry). Several points to know include the importance of folic acid (at least 0.4 mg daily) and adequate intake of iron and calcium. Additionally, certain fish are to be avoided during pregnancy and lactation (breastfeeding) due to possible high levels of methylmercury. The list of fish to avoid includes: shark, swordfish, king mackerel, and tilefish.
  5. Sexual intimacy. Generally, a pregnant woman may continue to enjoy sexual intimacy throughout her pregnancy, unless the obstetric provider instructs otherwise. Often sexual desire is diminished in the first trimester due to nausea and fatigue. In the third trimester, finding a comfortable position for intercourse will require open communication between the couple. Achieving orgasm, or a climax, is also safe throughout pregnancy, again unless restricted due to pregnancy complications by your obstetric provider.


After the initial prenatal visit, the obstetric provider will see most women monthly until the last months of the pregnancy. These shorter visits focus on any new concerns the woman has, checking for certain symptoms (such as headaches, leg swelling, uterine contractions, vaginal bleeding), and physical findings. The weight and blood pressure are measured at each visit, the urine is checked for sugar (diabetes) and protein (kidney problems), the baby is checked for adequate growth (by measuring the mother’s abdomen), and the baby’s heart tones are noted. Women are encouraged to bring along a list of any questions or concerns. In the last 8 weeks of the pregnancy, the visits become more frequent—often every 1-2 weeks.

Several additional tests are offered at certain times in the pregnancy:

  1. Serum alpha-feto protein test. This test of the pregnant woman’s blood provides a screen for congenital anomalies in the baby called neural tube defects (like spina bifida, where there is an incomplete formation of the spinal cord and its coverings) and the chromosomal anomaly called Down’s syndrome. The test actually involves evaluating the levels of four chemicals in the blood (so now known as a “Quad” screen) and must be accurately timed between 15 and 19 weeks of the pregnancy. Though only a screening test, any abnormality may or may not represent a true anomaly in the fetus, and may necessitate further testing by ultrasound or amniocentesis.
  2. Genetic counseling and amniocentesis. These services are offered to women with a personal or family history of genetic abnormalities, or if the woman will be 35 years or older when she delivers. An amniocentesis is a procedure in which a sample of the fluid surrounding the fetus (amniotic fluid) is withdrawn through a needle. The needle is guided by an ultrasound through the woman’s abdomen in such a way as to minimize any risks to the baby. The fluid is analyzed for the specific chromosomes.
  3. Ultrasound. The majority of pregnant women are offered at least one ultrasound, and the optimal timing for a single ultrasound is midway through the pregnancy (18-20 weeks). This study provides images of the fetus without the use of the radiation needed in standard x-rays (and therefore felt to be safe). The ultrasound will assess the baby for adequate growth, organ development, and placental location.
  4. Gestational diabetes screening. Some women are at risk to develop a form of diabetes in pregnancy known as gestational diabetes. In this condition, the mother-to-be’s blood sugars are higher than normal, and can lead to pregnancy complications, such as a very large baby at delivery and placental abnormalities. Most women are screened between 26 and 28 weeks of the pregnancy for this condition by a simple blood sugar test 1 hr after drinking a sugar solution. When identified, the condition is usually well controlled with a specific diet alone. In rare circumstances, treatment with insulin may be required.
  5. Blood antibody testing and RhoGam administration Human beings have one of several “types” of blood, depending on the genetic profile acquired from their parents. Blood is typed by two systems: ABO (types A, B, O, AB) and Rh (types positive and negative), and each individual will have a blood type with both designations (such as “O positive” or “AB negative”). Women with an Rh-negative blood type (about 15% of the population) may become “sensitized” by their baby’s blood during a pregnancy, which can affect future pregnancies. To prevent this potential complication, women with an Rh-negative blood type are given an injection of a medication called “RhoGam” at approximately 28 weeks and again after their delivery.
  6. Cultures for group B streptococcus. Approximately 30% of women will have a common bacterium, the group B streptococcus, present in the vagina at the time of their delivery. This bacterium often is present without any signs of an active infection like a vaginitis or bladder infection, but can infect the baby during the passage through the birth canal. To identify pregnant women at risk of this infection and offer antibiotics during labor and delivery, a simple vaginal culture is done about 1 month prior to the delivery date.


To fully understand and plan for the birth experience, the pregnant woman and her partner should attend childbirth education classes. These programs are often taught by experienced childbirth educators or nurses, and provide an understanding of the labor and birth process. These education classes include information on pain management, labor signs, help in designing a personal birth plan, and a tour of the hospital birthing center. Additionally, many programs offer classes on the care of the infant and breast-feeding. Most couples find these childbirth programs help in allaying fears, guiding toward more informed choices about the delivery, and building a sense of “team” between the woman and her partner.


The culmination of the pregnancy process is the delivery of a healthy baby. A pregnancy is at full term at 40 weeks of gestation, when measured from the first day of the last menstrual period. A woman will generally enter the beginning of labor between 37 and 41 weeks of gestation. Labors that begin before 37 weeks, or beyond 41 weeks, require special attention by the obstetric provider and the pediatric staff. The onset of labor is signaled by rhythmic uterine contractions that gradually increase in frequency, intensity, and duration. Occasionally the “bag of water” (amniotic fluid) will rupture before the onset of labor contractions. The woman may note a blood-tinged mucus discharge from the vagina 1-2 days prior to the onset of labor, often called the “mucus plug.” The obstetric provider will give instructions on when and how to contact the birthing center during the early labor stages.

The labor process is divided into three stages: The first stage is the longest and begins with the onset of contractions that dilate the cervix (birth canal). This first stage varies in length, with first-time mothers having the longest stage. The second stage begins with the full dilation of the cervix and is completed with the birth of the baby. This second stage generally lasts from 1 to 3 hr and includes a time when the mother actively assists the delivery of the baby by “pushing” or bearing down. The third and final stage of the birthing process includes the passage of the placenta or “afterbirth,” and is generally completed within 30 min of the birth of the baby.

SEE ALSO: Diabetes, Diet, Exercise, Labor and delivery, Nutrition, Pelvic examination, Physical examination

Suggested Reading

  • Johnson, R. V. (Ed.). (1994). Mayo Clinic complete book of pregnancy and baby’s first year. New York: William Morrow.
  • Gabbe, S. G. (Ed.). (2002). Obstetrics: Normal and problem pregnancies (4th ed.) New York: Churchill Livingstone.
  • Homan, D. D. (2000). Pregnancy. In R. Rakel (Ed.), Saunders manual of medical practice (pp. 636-639). Philadelphia: W.B. Saunders.


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