Prenatal Care Health Article

Definition

Prenatal care is that health care given to a pregnant woman and to the developing fetus until the time of delivery.

Purpose

The purpose of prenatal care is to:

• Establish a baseline for vital signs and current health status.
• Identify women at risk for pregnancy-related complications.
• Minimize pregnancy-related complications through prevention techniques, anticipatory action, and intervention as soon as a complication is recognized.
• Offer education to the woman about possible lifestyle and work-related dangers to her and the developing fetus.
• Provide routine evaluation of the growth and development of the fetus.
• Educate the pregnant woman about normal and abnormal conditions in pregnancy.
• Teach the woman to recognize the signs of impending labor.
• Assist in connecting the pregnant woman to child birth- and or parenting-education classes.

Precautions

Practitioners of prenatal care need to be aware of the possibility of domestic abuse, since such violence may begin with a pregnancy. About half of the women who are abused prior to becoming pregnant will continue to be abused during the pregnancy. Questions about abuse should be included at the first prenatal visit, and periodically thereafter if suspicion of it arises.

Description

The prenatal period lasts about 38 weeks from conception to delivery, or 40 weeks from the last menstrual period (LMP). It may also be referred to as the antenatal period. While some women come for their first prenatal visit shortly after missing a menstrual period, others may not come for prenatal care until later.

The first prenatal visit is usually the longest, as it includes a complete health history, physical examination (including pelvic and bimanual exams), and blood and urine testing. A recommended schedule for prenatal visits is:

• Once a month until 28 weeks' gestation.
• Every two weeks from week 28 to week 36.
• Every week from week 36 until delivery.

The pregnancy is confirmed at the first prenatal visit. A urine or blood test may be done as well as a physical examination. A woman may have taken a home pregnancy test after a missed period and may already be experiencing some nausea, vomiting, or breast tenderness. Practitioners should assess the woman's feelings about the pregnancy and assist in appropriate referrals if she needs further counseling.

The complete health history should record the following information:

• The first day of the woman's last menstrual period. The LMP date will be used to calculate the estimated date of delivery, referred to as the due date. Calculation of the due date uses a formula called Naegele's rule: subtract three months from the date of the woman's LMP. Then add one week and one year. Most women deliver within two weeks before or after their due date.
• Previous gynecologic and obstetric history. Practitioners should not assume that this is the woman's first pregnancy. A woman may not divulge her complete history if her partner is present and there are aspects of her history that she has not yet shared. This history should include contraceptive choices and prior exposure to sexually transmitted diseases. If she is Rhnegative, did she receive RHOgam with a previous pregnancy, even if it was terminated early?
• Personal medical history. This should include childhood diseases, allergies, side effects or allergies to medications, such chronic diseases as high blood pressure and diabetes, medications currently being taken, vaccinations, surgeries, and eating disorders. Past conditions may become reactivated during a pregnancy. Women with prior eating disorders may have difficulty gaining weight during a pregnancy. Women should be asked about medication taken before the pregnancy was suspected, as well as any unprotected exposure to x rays. The form of contraception at the time of conception needs to be established, and women should be asked if an intrauterine device (IUD) is in place.
• Family medical history, including ethnicity. Women may need screening if there is a family history of sickle-cell anemia, Tay-Sachs, cystic fibrosis, or thalassemia. Sometimes there is no family history but testing is still important if suggested by ethnic heritage. Women should be asked if there is a family history of retardation, developmental delay, reproductive loss, or other issues.

• Information about work, lifestyle, and hobbies. This information can be helpful in understanding potential risks for the pregnancy, such as alcohol, tobacco, or drug use, work- and hobby-related risks of chemical exposure or physical hazards, exercise patterns, possible exposure to Lyme disease, and nutritional intake. Does the woman's work require heavy lifting or continually standing in one place? Could she be exposed to chemicals that could be teratogenic to the fetus? Exercise during pregnancy helps with stress and anxiety, and most women can maintain their prepregnancy exercise routines during pregnancy. However, they need to avoid overheating, as this is harmful to the fetus. Overheating includes the use of saunas, hot tubs, and tanning beds. Exercise with potential trauma to the abdomen should be avoided. Exercise may be contraindicated in the case of intrauterine growth retardation, once the membranes have ruptured, vaginal bleeding, or for women at increased risk for preterm labor. The extent of the woman's support network should also be assessed. Does she have other children? Is she the primary caregiver for an ailing parent? Does the woman have cats or work in a veterinary office? (Toxoplasmosis is spread through soil, undercooked meat, and cat stool. Pregnant women should avoid contact with used cat litter, sand, or soil.)
• A verbal review of body systems, from head to toe. These questions may prompt a woman to remember or include information that she otherwise may have discounted as unimportant. It also establishes a baseline of her medical condition, especially if she develops symptoms later on in the pregnancy.
• Physical exam. The physical exam on the first visit will include a head-to-toe assessment in order to establish the presence of any abnormal or unusual findings, along with height, weight, and blood pressure. Women might be encouraged to continue, or begin, monthly breast self-exams for signs of lumps, and to report any physical changes such as thyroid enlargement or the development of varicose veins.

• Pelvic exam. The pelvic exam begins with an assessment of the external genitalia for any signs of redness, infection, vaginal discharge, or lesions. It will include a Pap smear for cervical cancer, as well as an assessment of the vaginal walls and cervix, checking for any growths, lesions, or signs of infection. The pregnancy will be confirmed by checking for changes in the uterine size. A bimanual exam allows the practitioner to check the uterus as well as the ovaries. A rectal exam checks for any rectal masses. The presence of hemorrhoids will also be noted. Cultures may be taken to check for infection or an undiagnosed sexually transmitted disease (STD), such as gonorrhea or chlamydia. Left untreated, these infections can be harmful to the mother and fetus. During the first visit the practitioner may also evaluate the adequacy of the pelvic size and shape for vaginal delivery.
• Fetal heart tones can be heard by 10 to 12 weeks' gestation. The normal fetal heart rate is 120 to 160 beats per minute. The fundal height will be measured at each visit to chart the growth pattern of the uterus.
• Laboratory work may include a urinalysis, complete blood count, rubella antibody titer, and blood type with Rh factor. Testing for hepatitis B is common. Women should be offered the option of HIV screening, as early detection can provide the opportunity of using medication to decrease the risk of transmission to the fetus. Additional screening may be done for toxoplasmosis, cytomegalovirus, herpes simplex, or group B streptococci.

Normal physical changes to expect during pregnancy should be discussed. The pregnant woman should also be given the emergency number to call when the health facility is closed, along with guidelines about when it is appropriate to call. Teaching about the use of over-thecounter medications should be done, as many people are not aware that nonprescription drugs can be harmful to the developing fetus. Before leaving from the first prenatal visit, the next appointment should be scheduled, to encourage ongoing care.

Subsequent prenatal visits are considerably shorter, unless complications arise. A routine visit includes a urine check for protein, glucose, and possibly ketones; a weight and blood-pressure check; and measurement of fundal height. At each visit the woman should be asked if she is experiencing any of the common discomforts of pregnancy, such as ankle edema (swelling), leg cramps, Braxton-Hicks contractions, fatigue, backache, nausea or vomiting, constipation, or shortness of breath. In the first trimester, and again toward the end of pregnancy, the uterus applies pressure on the bladder, possibly resulting in the need for frequent urination. If frequency is accompanied by burning or pain with urination, a urinary tract infection should be ruled out.

While nausea and vomiting are common until the fourth or fifth month of pregnancy, excessive vomiting can result in dehydration and electrolyte imbalance. Sometimes hospitalization is required. The new mother should also be educated about signs that might indicate a developing problem, such as abdominal pain (perhaps indicative of an ectopic pregnancy), edema in the face (preeclampsia), headaches, blurred vision, vaginal bleeding, continual vomiting, decrease in fetal movement, or presence of vaginal fluid (rupture of the amniotic membranes).

An opportunity should be provided to answer any questions the woman might have. Attendance at childbirth and/or parenting classes, and access to classes for older siblings, should be discussed. The pregnant woman should also be assessed for signs of depression. As the pregnancy progresses, lying supine can cause the uterus to compress the vena cava, impeding blood flow to the heart. This may be experienced as an irregular heart rate or a feeling of anxiety. Lying on the left side resolves this problem.

Pregnant women should be encouraged to eat a wide variety of nutritious foods. Women whose prepregnancy weight is within an appropriate range for height should expect to gain about 25 to 35 pounds over the course of the pregnancy. Those who are overweight should gain less, but not try to diet while pregnant. Pica, or the desire to eat nonfood substances, may not cause harm to the fetus if the substances themselves are not harmful and the woman is otherwise eating a balanced diet. Questions to assess for pica should be part of routine visits. A woman's financial situation can affect her ability to purchase nutritious foods. This need should be assessed at the first visit so that an appropriate referral can be made for food stamps or other assistance programs. The use of megavitamins should be evaluated, as high doses of fat-soluble vitamins can be harmful. Intake of high doses of vitamin A is associated with birth defects.

At 10 to 18 weeks, genetic counseling may be provided for women with a family history of congenital, chromosomal, or neural-tube anomalies, or for women above age 35. Chorionic villi sampling (CVS) may be done between 10 and 12 weeks, while amniocentesis may be performed between 14 and 18 weeks. Ultrasound may be done between 12 and 24 weeks to confirm dating of the pregnancy or to check fetal anatomy.

A triple marker screen test that evaluates maternal serum alpha-fetoprotein, human chorionic gonadotropin (hCG), and unconjugated estriol levels is usually run on a blood sample between 16 and 20 weeks to screen for neural-tube defects. Inadequate intake of folic acid is associated with such neural-tube defects as spina bifida. Elevated levels of alpha fetoprotein may indicate a neural-tube defect, but can also be due to a multiple pregnancy, inaccurate dates, or fetal death. The test can also indicate if the fetus has Down's syndrome. As with other laboratory tests, false positives can occur.

At 20 to 22 weeks, women should be aware of the danger of premature rupture of the membranes and preterm labor. Fundal height should be at the umbilicus.

Screening for gestational diabetes is done around 26 to 28 weeks. The first screening test does not require fasting, and blood is drawn once, an hour after a drink containing 50 gm of glucose is ingested. If the result is abnormal in any way, a three-hour glucose tolerance test (GTT) will be administered. This test is usually done in the morning, after the woman has fasted for eight hours. A sample for the FBS (fasting blood sugar) test is drawn, glucose is given, and blood is then drawn hourly over the next three hours. Babies of mothers with gestational diabetes are at risk of excessive intrauterine growth, and blood sugar abnormalities after birth. While gestational diabetes (GDM) usually resolves when the pregnancy terminates, women with GDM are at increased risk—about 60%—of developing diabetes within the next 16 years.

From 28 weeks to 34 weeks onward, fetal presentation (position) will be checked at each visit.

After 36 weeks the physician may choose to conduct a sterile internal exam to evaluate the condition of the cervix for labor and delivery.

From 40 to 42 weeks fetal well-being and the amount of amniotic fluid may be monitored more closely. Too little or too much may indicate problems. Induction of labor will be considered.